Clinical practice guideline "preconception care".

This guideline represents an expert consensus-based practice guideline informed by a critical appraisal of the available literature. The guideline development process followed the principles of the AGREE II framework: the scope and target population were predefined (Domain 1), a multidisciplinary expert panel was involved (Domain 2), recommendations were based on structured literature review and graded evidence (Domain 3), the guideline was designed for clinical applicability in routine preconception care (Domains 4–5), and editorial independence and conflict of interest management were ensured (Domain 6). The guideline followed a structured and transparent consensus process grounded in evidence-based guideline methodology. It was developed under the auspices of the Swiss Society of Gynecology and Obstetrics (SSGO) Quality Assurance Committee. The guideline panel comprised 20 clinical experts representing all major gynecological sub-specialties, as well as a representative of a patient organization. The coordinating authors defined the scope, objectives, and key clinical domains of the guideline. For each thematic section, a designated lead author drafted the content based on a critical appraisal of the relevant medical literature, including international guidelines, systematic reviews, meta-analyses, and key original studies. All co-authors reviewed each section, provided substantive input, and critically assessed the underlying evidence. An iterative consensus process was used to agree on the wording of recommendations, their clinical relevance, and their grading. Levels of evidence were assigned according to the Oxford Centre for Evidence-Based Medicine (OCEBM) Levels of Evidence [ 13 ]. The strength of recommendations was graded using a standardized A–D recommendation scheme, reflecting the quality, consistency, and applicability of the available evidence [ 14 ] (see Appendix A). The complete draft guideline underwent repeated review and discussion within the expert panel with regard to clinical accuracy, completeness, internal consistency, and practical applicability. Feedback was incorporated into the final version once consensus was achieved. All authors disclosed potential financial and non-financial conflicts of interest prior to guideline development. No relevant conflicts were identified. The guideline was developed independently and without influence from any external funding body or commercial entity. The recommendations in this guideline are based on a structured review of the available evidence, including international clinical practice guidelines, systematic reviews, meta-analyses, and large observational studies. Evidence quality and recommendation strength were assessed using predefined levels of evidence and Grade methodology. Where high-quality evidence was available, strong recommendations were formulated. In areas with limited or heterogeneous evidence, recommendations were issued as conditional recommendations or good practice points based on expert consensus, clinical relevance, and consistency with existing international guidelines (see also Appendix B). Preconception counseling should be seen as a multi-stage process and not as a single appointment. Ideally, it should take place as part of regular gynecological check-ups and be extended as required. The key points of preconception counseling are an evaluation of the general health status and associated risks to fertility and pregnancy, advice on reducing or eliminating risks, optimizing health and initiating interventions to achieve the above-mentioned goals. Preconception counseling ideally takes place before the couple is planning a pregnancy and, for example, stops using contraception. However, almost half of all pregnancies are unplanned [ 15 ]. [LoE: IIb, Grade C]. In a large meta-analysis of over 500,000 pregnancies, Nelson et al. were able to show that unplanned pregnancies have higher fetal and maternal morbidity than planned pregnancies [ 16 ]. [LoE: IIa]. Some interventions and behavioral changes to optimize pregnancy outcomes take several weeks to months before the onset of pregnancy to take effect—so they need to be started with adequate lead time. One possible approach could be to use the simple question: "Would you like to get pregnant in the coming year?" as a pivotal point for further advice [ 17 ]. There is no standard definition of an "ideal age" for pregnancy, but the risk of infertility and morbidity during pregnancy generally increases from age 30 onward: Decreasing pregnancy rate: the rate of pregnancies gradually decreases from the age of 32 [ 18 ]. Dunson et al. showed that the pregnancy rate at the age of 19–26 is twice as high as at the age of 35–39 [ 19 ] [LoE: IIb]. Increased risk of miscarriage: the association between maternal age and miscarriage risk is well-documented. Magnus et al. showed in a Norwegian registry study that the risk of miscarriage is lowest in the 25–29 age group and increases from then on [ 20 ] . Andersen et al. showed in a Danish registry study that the risk of spontaneous miscarriage is 12% in this age group, 15% up to the age of 35, 25% up to the age of 39 and even 51% at the age of 40–44 [ 21 ] [LoE: IIb]. Increase in the frequency of aneuploidies (numeric chromosomal abnormalities): due to oocyte aging, the risk of aneuploidies increases with maternal age; it is in the range of 2.6 per 1000 live births at 30 years, 5.6 per 1000 live births at 35 years, 15.6 per 1000 live births at 40 years and 53.7 per 1000 live births at 45 years [ 22 ]. The number of aneuploidies in early pregnancy that do not survive to birth is much higher [LoE: IIb]. Decreasing pregnancy rate: the rate of pregnancies gradually decreases from the age of 32 [ 18 ]. Dunson et al. showed that the pregnancy rate at the age of 19–26 is twice as high as at the age of 35–39 [ 19 ] [LoE: IIb]. Increased risk of miscarriage: the association between maternal age and miscarriage risk is well-documented. Magnus et al. showed in a Norwegian registry study that the risk of miscarriage is lowest in the 25–29 age group and increases from then on [ 20 ] . Andersen et al. showed in a Danish registry study that the risk of spontaneous miscarriage is 12% in this age group, 15% up to the age of 35, 25% up to the age of 39 and even 51% at the age of 40–44 [ 21 ] [LoE: IIb]. Increase in the frequency of aneuploidies (numeric chromosomal abnormalities): due to oocyte aging, the risk of aneuploidies increases with maternal age; it is in the range of 2.6 per 1000 live births at 30 years, 5.6 per 1000 live births at 35 years, 15.6 per 1000 live births at 40 years and 53.7 per 1000 live births at 45 years [ 22 ]. The number of aneuploidies in early pregnancy that do not survive to birth is much higher [LoE: IIb]. Paternal age should also be considered: increased paternal age, above 40 years [ 23 ], has been associated with increased risk of miscarriage, prolonged time to conception, increased rate of single-gene mutations and lower birth weight [ 23 – 26 ] [LoE: IIb; Grade B]. In general, a woman should be informed, regardless of her current desire to have children that fertility decreases after the age of 30 and especially after the age of 35 and that pregnancy complications increase with increasing age after the age of 35. In the case of infertility, further evaluation is recommended after 12 months up to the age of 35, and after 6 months after the age of 35 [ 10 , 27 ] [LoE V; Grade D]. If the woman is under the age of 40 and the couple has regular unprotected sex, 80% of all couples become pregnant within a year [ 10 ] [LoE: IIb]. Before pregnancy, the best possible approximation of body weight to a normal weight is desirable [Grade D]. Obesity : Women with a BMI (body mass index) > 30 have a higher risk of nutritional deficiencies than non-obese women [ 28 ] (LoE IIa, Grade B) as well as increased risks of infertility, miscarriage and unfavorable pregnancy outcome [ 8 , 28 , 29 ] (LoE Ia, Grade A). In addition, they have an increased risk of contraceptive failure, so there is a risk of unplanned pregnancies (LoE III, Grade B). It is advisable to take a BMI at every medical consultation and, in the case of obesity, to point out the benefits of even minor weight loss before pregnancy to women who are potentially planning a pregnancy [ 30 ] (LoE III, Grade B). If the BMI is very high, treatment methods such as bariatric surgery or GLP-1 receptor agonists can also be considered. However, GLP-1 receptor agonists are currently contraindicated in pregnancy, so contraception is necessary when using them. As there is an increased risk of undiagnosed diabetes, it may be useful to screen for it using HbA1c (HbA1c  30 kg/m 2 ) have an increased risk of macrosomia, gestational diabetes, pre-eclampsia, premature birth and associated birth complications (LoE Ia, Grade A). A Canadian population-based study showed that reducing preconception BMI by 10% reduces the risk of gestational diabetes, pre-eclampsia, macrosomia and fetal demise by 10% [ 31 ] (LoE IIa, Grade B). Post-bariatric surgery: After bariatric surgery, a pregnancy should be delayed by at least 12 months, as otherwise there is a risk of fetal malnutrition and postoperative complications [ 28 , 32 , 33 ] (LoE IIb, Grade B). Interdisciplinary care in a center is strongly recommended (Grade D). Underweight : Women with a BMI < 18.5 also have an increased risk of nutritional deficiencies, infertility, miscarriage and unfavorable pregnancy outcomes [ 8 ] (LoE IIa, Grade B). Even if the BMI alone does not fully reflect the nutritional situation, women with a BMI  18.5 should be aimed for if they are planning a pregnancy [ 6 ] (LoE III, Grade C). A meta-analysis of physical activity showed 7 studies in which the risk of gestational diabetes was reduced by 55% in pregnant women with the highest activity compared to those with the lowest (LoE Ia, Grade A). The physical activities consisted of walking and stair climbing; high intensities were more effective than low intensities. Physical activity to prevent gestational diabetes before pregnancy was more effective than during pregnancy. The available evidence suggests that lifestyle changes, especially increased physical activity, reduce the risk of developing gestational diabetes (LoE Ia, Grade A). The WHO recommends at least 150 min of moderate-intensity exercise per week for adults [ 34 ] (LoE Ia, Grade A). This can be continued during pregnancy. Sports with a high injury potential (contact sports or risk of falling) or diving is not recommended during pregnancy [ 35 ] (LoE IIIa, Grade B). Women who are planning a pregnancy should undergo a dental health check and, if necessary, be treated. Untreated periodontitis is associated with an increased risk of premature birth and FGR [ 36 ] (LoE IIa, Grade B). Folic acid is the synthetic form of the naturally occurring vitamin B9 = folate. The connection between folic acid and neural tube defects has been known since the 1970 s. Preconceptional intake of folic acid can reduce the incidence of neural tube defects by up to 70% [ 37 ][LoE Ib, Grade A]. While a large proportion of women are aware of the link between folic acid and neural tube defects, only a fraction take the supplement correctly and timely; this applies in particular to women with a migration background and unplanned pregnancies [ 38 ] (LoE III, Grade C). A dose of at least 400 mcg folic acid per day for at least 1 month before conception has been established (LoE Ia, Grade A), possibly as a combination preparation with other vitamins A dose of 800mcg folic acid per day is recommended in the following situations (LoE IIa, Grade A): o After bariatric surgery [ 32 , 39 ]. A higher dose of 5 mg folic acid per day is recommended in the following situations [LoE IIa A]: o after a child with a neural tube defect [ 8 , 12 , 32 , 40 , 41 ]. o First-degree relatives of a child with a neural tube defect [ 8 , 12 , 32 , 40 , 41 ]. o Antiepileptic drug therapy [ 8 , 12 , 42 ]. o Pre-existing diabetes [ 9 ]. o BMI > 35 [ 8 ]. o MTHFR mutation [ 43 ]. The 5 mg dose for increased risk is recommended from 3-month preconception up to the 12th week of pregnancy, then reduced to 400 or 800 mcg per day Naturally occurring folate can be found in leafy vegetables, tomatoes, pulses, nuts, oranges, sprouts, wholegrain products, potatoes and eggs [ 44 ], although the intestinal absorption of folate is poorer than that of folic acid and folate is largely destroyed when food is heated. In principle, however, it is also possible to cover the requirement with natural folate. Countries with folic acid enrichment in flour show a 30–46% reduction in cases of neural tube defects [ 38 , 42 ] [LoE IIb, Grade B]. Folic acid is the synthetic form of the naturally occurring vitamin B9 = folate. The connection between folic acid and neural tube defects has been known since the 1970 s. Preconceptional intake of folic acid can reduce the incidence of neural tube defects by up to 70% [ 37 ][LoE Ib, Grade A]. While a large proportion of women are aware of the link between folic acid and neural tube defects, only a fraction take the supplement correctly and timely; this applies in particular to women with a migration background and unplanned pregnancies [ 38 ] (LoE III, Grade C). A dose of at least 400 mcg folic acid per day for at least 1 month before conception has been established (LoE Ia, Grade A), possibly as a combination preparation with other vitamins A dose of 800mcg folic acid per day is recommended in the following situations (LoE IIa, Grade A): o After bariatric surgery [ 32 , 39 ]. After bariatric surgery [ 32 , 39 ]. A higher dose of 5 mg folic acid per day is recommended in the following situations [LoE IIa A]: o after a child with a neural tube defect [ 8 , 12 , 32 , 40 , 41 ]. o First-degree relatives of a child with a neural tube defect [ 8 , 12 , 32 , 40 , 41 ]. o Antiepileptic drug therapy [ 8 , 12 , 42 ]. o Pre-existing diabetes [ 9 ]. o BMI > 35 [ 8 ]. o MTHFR mutation [ 43 ]. after a child with a neural tube defect [ 8 , 12 , 32 , 40 , 41 ]. First-degree relatives of a child with a neural tube defect [ 8 , 12 , 32 , 40 , 41 ]. Antiepileptic drug therapy [ 8 , 12 , 42 ]. Pre-existing diabetes [ 9 ]. BMI > 35 [ 8 ]. MTHFR mutation [ 43 ]. The 5 mg dose for increased risk is recommended from 3-month preconception up to the 12th week of pregnancy, then reduced to 400 or 800 mcg per day Naturally occurring folate can be found in leafy vegetables, tomatoes, pulses, nuts, oranges, sprouts, wholegrain products, potatoes and eggs [ 44 ], although the intestinal absorption of folate is poorer than that of folic acid and folate is largely destroyed when food is heated. In principle, however, it is also possible to cover the requirement with natural folate. Countries with folic acid enrichment in flour show a 30–46% reduction in cases of neural tube defects [ 38 , 42 ] [LoE IIb, Grade B]. Calcium : There is no convincing evidence that calcium supplementation initiated preconceptionally beyond the recommended dietary intake provides additional benefits for neonatal outcomes, as shown in guideline-level reviews and systematic analyses [ 7 , 45 ] Evidence on calcium supplementation started before or very early in pregnancy for prevention of hypertensive disorders is limited to a single small trial, suggesting a possible reduction in a composite outcome, including pre-eclampsia and pregnancy loss, but results are inconclusive and insufficient to support routine use [ 46 ]. Women planning pregnancy should aim to meet the recommended daily calcium intake of 1000mg [ 47 ] through diet, with supplementation considered only if dietary intake is clearly insufficient or if they are in populations with endemic low calcium intake [LoE IIb, Grade B]. Omega-3 fatty acids : Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are two so-called omega-3 fatty acids. Omega-3 supplementation during pregnancy has been shown to reduce preterm birth [ 48 ] There might also be a possible beneficial effect on neurodevelopment, although the evidence is limited. Women planning pregnancy should be encouraged to ensure a regular dietary supply of omega-3 fatty acids primarily via omega-3-rich foods (e.g., fish/seafood). A pragmatic preconception target is ≥ 250 mg/day EPA + DHA (European reference intake for adults) [ 49 ] to enter pregnancy with adequate baseline status. Where dietary intake is insufficient, omega-3 supplementation can be used to meet the above intake target [LoE Ia, Grade B]. Vitamin B12 : It is primarily found in animal products and is, therefore, deficient in vegetarian and vegan diets. As folic acid and vitamin B12 metabolism are interlinked, attention should also be paid to an adequate intake, supplemented if necessary, of vitamin B12 to avoid neural tube defects [ 8 , 40 ] (LoE IIa, Grade B). Outside of pregnancy, the recommended daily intake is 4.0 mcg for adults and 4.5 mcg for pregnant women in Germany, Austria and Switzerland [ 50 ], while the NHS (National Health Service) recommends 1,5mcg [ 51 ] and the NIH (National Institute of Health) at least 2,4mcg for adults and 2,6mcg for pregnant women [ 52 ]. Information on the vitamin B12 content of various foods can be found here: https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/#h4 If a vitamin B12 deficiency is suspected (due to diet and/or macrocytic anemia), holotranscobalamin (active vitamin B12, which is bound to transcobalamin) should be checked and, if necessary, substituted [LoE IIb, Grade B]. Vitamin D : A woman’s vitamin D requirement increases during pregnancy, as the fetus is completely dependent on the mother’s vitamin D supply for growth and development (LoE IIa, Grade B). It is, therefore, important to achieve and maintain adequate vitamin D levels before conception. The European recommendation for Vitamin D uptake is 15mcg or 600 IE per day for adults [ 53 ]. A study from Switzerland, however, showed that a large number of pregnant women have a severe vitamin D deficiency at the beginning of pregnancy [ 54 ], suggesting that even a higher vitamin D dose, e.g., 800 IE per day, is already indicated preconceptionally. The requirement may be even higher for vegetarians, people of color or those who live in environments with limited sun exposure [ 8 ] (LoE IIB, Grade B). Iodine : From a global perspective, iodine recommendations depend on a country’s proximity to the sea and national food fortification policies. Recommendations, therefore, vary. While in the USA, Canada and Australia, 150mcg of daily iodine intake is recommended for pregnant women, the recommendation from the European Food Safety Authority EFSA gives 200mcg daily as a recommendation for pregnant women and in Germany, Austria and Switzerland the recommendation ranges from 200 to 250mcg per day [ 55 ]. It is reasonable to preconceptionally replenish iodine stores sufficiently to cover the increased requirement during pregnancy [ 8 ] (LoE IIa, Grade A). According to a recent cross-sectional study from Switzerland, iodine intake among pregnant women was too low despite a national iodization program [ 56 ]. Processed foods usually contain iodine-free salt [ 56 ], so it is essential to ensure sufficient intake by means of iodized table salt or dietary supplements (LoE IIB, Grade B). Vegan and vegetarian diets : A vegetarian or vegan diet during preconception and pregnancy is generally feasible and not associated with increased maternal or fetal morbidity, provided that adequate nutrient intake is explicitly ensured [ 57 , 58 ]. Special attention should be given to folate, vitamin B12, and iron status, as well as to docosahexaenoic acid (DHA, omega-3 fatty acid), calcium, iodine, and zinc [ 59 ] (see above) (LoE III, Grade C). Ketogenic diet : A ketogenic diet is characterized by high fat and very low carbohydrate intake. Evidence from animal models indicates potential adverse effects on fetal development and offspring neuroanatomy, while human data remain limited and inconsistent (LoE IIIB–IV, Grade C). Potential mechanisms include maternal glucose deprivation, elevated ketone bodies, oxidative stress, epigenetic alterations, and micronutrient shortfalls that may impair fetal organ and brain development. In view of insufficient and conflicting human data and concerning animal findings, ketogenic diets are not recommended during pregnancy (LoE IV, Grade D). To meet maternal–fetal glucose needs, a minimum carbohydrate intake of 175 g/day is advised (based on Dietary Reference Intakes), with clinical nutrition management individualized as needed [ 60 , 61 ] (LoE IV, Grade C). Intermittent fasting : Periods of fasting may increase cortisol levels; therefore, intermittent fasting is not recommended during preconception and pregnancy. Extended fasting intervals may compromise a constant supply of nutrients and energy, potentially destabilizing maternal blood glucose levels (LoE IIIb, C). National societies provide practical resources: the German Nutrition Society (DGE) [ 59 ], the British Dietetic Association (BDA) [ 62 ], or the American College of Obstetricians and Gynecologists (ACOG) [ 63 ] offer comprehensive information sheets that can be referred to women planning pregnancy or those with special dietary needs. Current reference values are country specific. For women with specific dietary practices or those at increased risk of malnutrition, professional nutrition counseling is recommended to optimize diet in the preconception period [ 7 ]. Iron deficiency and exclusion of anemia: iron deficiency and anemia should be excluded preconceptionally, as iron deficiency with or without anemia at the beginning of pregnancy is associated with maternal complications and anemia with fetal complications (low birth weight, premature birth) [ 36 , 64 , 65 ] (LoE Ia, Grade A). However, undirected iron supplementation should generally be avoided, as a high hemoglobin level in pregnancy is also associated with an increased risk of low birth weight [ 36 ] (LoE IIb, Grade B). Nicotine : Periconceptional nicotine consumption is associated with an increased rate of miscarriages [ 66 ]; this also applies to passive smoking [ 67 ]. Nicotine consumption during pregnancy is associated with premature birth, premature rupture of membranes, low birth weight, placenta previa and premature placental abruption as well as intrauterine fetal death (LoE Ia). Stopping smoking can lead to a risk reduction close to the baseline risk [ 68 , 69 ] (LoE Ib, Grade B). Patients and their partners should, therefore, be encouraged and, if necessary, actively supported with counseling and drug therapy to stop smoking or at least drastically reduce smoking before discontinuing contraception. This recommendation also applies to vaporizers and heated tobacco products, although here, solid data are still lacking (LoE III, Grade C). Alcohol : Fetal alcohol spectrum disorder (FASD) is among the most common preventable causes of neurodevelopmental disability worldwide, with a global prevalence estimated at 1–5% of live births [ 70 ] (LoE Ia). Despite public health efforts, surveys from several countries demonstrate that a substantial proportion of women continue to consume alcohol during pregnancy. In a survey from Switzerland in breastfeeding women, 18% stated that they consumed alcohol at least once a week. 6% stated that they drink "too much" at least occasionally [ 71 ]. It is well-established that there is no safe threshold for alcohol intake during pregnancy [ 72 ] (LoE Ia, Grade A). Because of the potentially severe and irreversible outcomes, professional societies and international health organizations recommend complete abstinence from alcohol during the periconceptional period and throughout pregnancy [ 73 ] (Grade A). THC/cannabinoids : In some European populations, cannabis use before pregnancy is reported to be about 4–5% among women of reproductive age [ 74 – 77 ], while during pregnancy, the prevalence tends to drop to around 1–3% in these studies. Due to the potentially harmful effects of cannabis use during pregnancy on child development, cannabis use should be discouraged even before conception and at the latest once pregnancy occurs (LoE IIb, Grade B). Cocaine : Periconceptional and prenatal cocaine use is associated with significant maternal and fetal risks, including miscarriage, placental abruption, preterm birth, fetal growth restriction, and intrauterine fetal death, largely mediated through potent vasoconstrictive and hypertensive effects. Cocaine readily crosses the placenta, and even intermittent use has been linked to acute placental ischemia and fetal hypoxia. In addition, cocaine use in pregnancy is associated with adverse neonatal outcomes, including neonatal abstinence symptoms and long-term neurodevelopmental impairment [ 78 ]. Women planning pregnancy should, therefore, be strongly advised to cease cocaine use before conception, and structured addiction counseling and specialist support should be offered (LoE IIa, Grade B). Opioids : Use of opioids before and during pregnancy—both illicit opioids (e.g., heroin) and non-medical use of prescription opioids—is associated with increased risks of miscarriage, preterm birth, fetal growth restriction, stillbirth, and neonatal abstinence syndrome (NAS). Abrupt cessation in dependent women may provoke withdrawal, which itself can endanger pregnancy; therefore, preconception identification of opioid use and referral to specialized care are essential. For women with opioid use disorder, opioid agonist therapy (e.g., methadone or buprenorphine) initiated or optimized before conception is associated with improved maternal stability and pregnancy outcomes compared with continued illicit use. Opioid use should be actively addressed already in the preconception period [ 79 , 80 ] (LoE IIa, Grades A–B). In general, the 5A method is recommended for the care of patients with substance use [ 81 ]: Ask—Systematically ask about consumption. Advise—Provide information about the benefits of the stop and give a clear recommendation. Assess—Determine readiness to suspend. Assist—providing support with weaning or reduction. Arrange—Organize follow-up. Caffeine : According to the European Food Safety Authority (EFSA), 200 mg of caffeine per day is considered a safe dose during pregnancy [ 82 ] (LoE IIa, Grade B). It is usually sufficient to reduce caffeine consumption immediately upon becoming pregnant (Table  1 ). Table 1 Caffeine content of foods; estimates; table according to www.efsa.europa.eu/en/topics/topic/caffeine Espresso, 60 ml 80 mg caffeine Filter coffee, 200 ml 90 mg Black tea, 220 ml 50 mg Green tea, 220 ml 33 mg Can of cola, 255 ml 40 mg “Standard Energy Drink" can, 250 ml 80 mg Dark chocolate, 50 g 25 mg Milk chocolate, 50 g 10 mg Caffeine content of foods; estimates; table according to www.efsa.europa.eu/en/topics/topic/caffeine As live vaccinations should be avoided during and for at least a month before pregnancy, it is recommended that the vaccination status should be checked before a planned pregnancy to ensure that all vaccinations are up to date. Recommendations might vary slightly according to country guidelines, but usually contain: Measles, rubella: at least one (usually 2) documented vaccination [ 83 ] [LoE Ia, Grade A]. Varicella: documented past disease or immunity (IgG) or 2 documented vaccinations, at least 4 weeks apart [ 84 ] [LoE Ia, Grade A]. Measles, rubella: at least one (usually 2) documented vaccination [ 83 ] [LoE Ia, Grade A]. Varicella: documented past disease or immunity (IgG) or 2 documented vaccinations, at least 4 weeks apart [ 84 ] [LoE Ia, Grade A]. Cytomegalovirus (CMV) : Preconceptional CMV serology can help to interpret unclear findings in early pregnancy [ 85 ]. This is particularly useful for women in at-risk populations, i.e., with close contact with children under the age of four (mothers and child careers). These women should also be made aware of the hygiene recommendations for transmission prophylaxis prior to conception [LoE III, Grade C]. Chagas disease : Chagas is a disease prevalent in Mexico and Central and South America. Women with a sociocultural background in these countries, have an increased risk for Chagas, and are often unaware of their infection. As treatment in pregnancy is contraindicated, prepregnancy screening and treatment are useful in preventing vertical transmission [ 86 ] [LoE III, Grade B]. Toxoplasmosis : Toxoplasmosis should be addressed in a limited and targeted manner within preconception care, focusing on risk-mitigation counseling rather than screening. Women planning pregnancy, particularly those with potential exposure (e.g., consumption of raw or undercooked meat, soil contact, or cat litter), should be advised on basic hygiene measures to reduce the risk of primary infection [ 87 ] [LoE IV, Grade D]. Listeria : Women planning pregnancy should be advised to avoid foods with an increased risk of Listeria monocytogenes and other foodborne bacterial infections that are particularly harmful in early pregnancy. These include unpasteurized milk and dairy products, especially soft cheeses (e.g., Brie, Camembert and blue-veined cheeses), as well as ready-to-eat refrigerated foods, such as deli meats, pâtés, meat spreads, smoked fish, and pre-prepared salads, unless they are reheated until steaming hot. In addition, raw or undercooked meat, raw fish (e.g., sushi and sashimi), and raw or lightly cooked eggs (e.g., soft-boiled eggs, homemade mayonnaise, or desserts) should be avoided [ 88 ]. Because Listeria can multiply at refrigerator temperatures and early pregnancy is often unrecognized, establishing safe dietary habits before conception is a simple and effective preventive measure. [LoE IIa–IIb, Grade B]. These are usually cardiovascular, nephrological, hematological, rheumatological, endocrinological, psychiatric or neurological problems. Preconception counseling should be carried out on an interdisciplinary basis as early as possible. The aim must be to recognize the risks and to inform and advise the patient about them and, if necessary, to carry out a specific intervention. The following questions are important: What risks does the health issue itself pose for the pregnancy? (Examples: fetal heart defects due to periconceptional poorly controlled diabetes) How does pregnancy influence the medium and long-term course of the disease? (Examples: pre-existing renal insufficiency worsening during pregnancy and subsequent need for dialysis). What risks for the pregnancy are associated with drug therapy for the disease (Examples: antiepileptic drugs and risk of neural tube defects)? What risks does the health issue itself pose for the pregnancy? (Examples: fetal heart defects due to periconceptional poorly controlled diabetes) How does pregnancy influence the medium and long-term course of the disease? (Examples: pre-existing renal insufficiency worsening during pregnancy and subsequent need for dialysis). What risks for the pregnancy are associated with drug therapy for the disease (Examples: antiepileptic drugs and risk of neural tube defects)? The following table provides an overview of the most common maternal health problems, the associated maternal and fetal risks, treatments and goals (Table  2 ). Table 2 Maternal health problems and approach options Pre-existing conditions Associated maternal and fetal risk Treatment Goal Diabetes mellitus (LoE Ia, Grade A) pregnancy associated complications, malformations, miscarriage, neonatal adaptation disorders [ 12 ] Euglycemic control, weight control, vasculopathy clarification (retinopathy, nephropathy, ECG), thyroid function HbA1c < 6.5% (below 48 mmol/mol) to reduce the risk of malformations Morning fasting glucose 5–7 mmol/L, 4–7 mmol/l preprandial [ 9 ] Chronic hypertension (LoE Ib, Grade A) Pre-eclampsia and growth restriction Teratogenic risk due to antihypertensive drugs (ACE inhibitors, angiotensin receptor blockers); switch to pregnancy-compatible medication Examination for end organ damage: ventricular hypertrophy (ECG), retinopathy and kidney disease (proteinuria) in the case of long-standing, not well-controlled hypertension Switch to medication that has a better safety profile during pregnancy. examples for initial dosage: Methyldopa: 2–3 × 250 mg/d max. 2g/d Labetolol: 2 × 100 −200 mg/d, max 4 × 300mg/d Nifedipine retard: 30–60 mg/d, max. 120 mg/d Metoprolol 25–100mg/d max. 200 mg/d [ 89 ] Hypothyroidism (LoE IIa, Grade B) Miscarriages, pre-eclampsia, premature births, premature placental abruption, fetal demise Screening for risk factors (e.g., > 30 yrs, obesity, recurrent abortions, premature birth, infertility) Treatment, if TSH > upper limit value Hyperthyroidism (LoE IIb, Grade B) Miscarriages, premature birth, fetal demise, low birth weight Differential diagnosis and treatment Euthyroid metabolic state Psychiatric illnesses (LoE IIb, Grade B) Disturbed mother–child bonding, antidepressants and antipsychotics increase the risk of anovulation and reduce fertility Counseling for depression, anxiety disorders regarding risks and benefits of treatment. Risk of relapse higher in bipolar disorder during pregnancy. Strategy planning for management. Advise on risks and treatment plan for schizophrenia Psychiatric medication should not be discontinued before conception or at the beginning of a pregnancy to reduce the risk of relapse. If necessary, it should be switched to a medication compatible with pregnancy Epilepsy [ 90 ] (LoE Ia, Grade A) Teratogenic and long-term risk due to specific antiepileptic drugs when taken by the mother or possibly the father (for Valproate, see [ 91 , 92 ]). medication switch usually over 3 months Advice on the impact of pregnancy on seizure frequency Switch to lamotrigine, levetiracetam, carbamazepine Folic acid prophylaxis 5mg/d Avoidance of Valproate-containing preparations HIV (LoE Ia, Grade A) See separate Practice Guideline 60 [ 93 ] Thrombophilia (LoE Ia, Grade A) Deep vein thrombosis or pulmonary embolism during pregnancy or postpartum, frequent occurrence in the family Advice on the need for thromboprophylaxis during pregnancy/postpartum [ 94 ] Complications during previous pregnancy (LoE IIb, Grade B) Risk of recurrence in further pregnancies Survey and advice on the risk of recurrence (see below) Hemoglobinopathy (LoE IIa, Grade B) Miscarriage, fetal anemia Genetic counseling for couples at risk of thalassemia or sickle cell anemia Cardiovascular diseases, aortic diseases, pulmonary hypertension [ 95 ] (LoE IIa, Grade B) Maternal mortality, myocardial infarction, pericardial myopathy, aortic dissection, premature birth Risk assessment and counseling for all women with known or suspected congenital or acquired cardiovascular and aortic disease or pulmonary hypertension. Echocardiography is recommended for all pregnant patients with unexplained or new cardiovascular signs or symptoms Multiple sclerosis [ 96 ] (LoE IIb, Grade B) Teratogenic or long-term risk due to specific immunotherapies; this may also apply if taken by the partner. Effective contraception recommended for at least 6 months [ 96 ] Advise and planning of pregnancy, adjustment of medication [ 97 ] Asthma [ 98 ] (LoE Ia, Grade A) Uncontrolled asthma and an exacerbation increase the risk of pre-eclampsia, growth restriction, preterm birth Advice and information to women that well-controlled asthma has no negative effect on pregnancy. Adjustment of medication and no abrupt discontinuation Short-term β-agonists Long-term β-agonists (LABA—salmeterol, Inhaled corticosteroids (alone or in combination with LABA) Autoimmune rheumatic diseases [ 99 ], e.g., rheumatoid arthritis, spondyloarthritis, systemic lupus erythematosus, antiphospholipid AK, systemic sclerosis, mixed connective tissue) (LoE IIa, Grade B) Pre-eclampsia, hypertension, growth restriction Consultation and risk stratification; Adjustment to medication suitable for pregnancy, stable situation during 6–12 mo before pregnancy, check for anti Ro/SSA ± anti La/SSB, aPL profile (lupus anticoagulans, anti-Cardiolipin AK, anti b2 glycoproteins) no cyclophosphamide, methotrexate, thalidomide, mycofenolate mofetil Solid organ transplantation [ 100 ] (LoE IIb, Grade B) Increased risk of rejection reaction, deterioration of organ function, premature birth, growth restriction, teratogenic risk due to specific drugs -Checking the kidney function -Assessment of the function of the transplanted organ (e.g., echocardiogram, lung function test -Determination of HLA antibodies -Upper abdominal sonography and liver function tests Patients should be vaccinated against influenza, pneumococci, varicella zoster, COVID 19 (hepatitis A/B, diphtheria, polio, pertussis and tetanus, optionally against meningococci and human papillomaviruses before a planned pregnancy [ 101 ] Maternal health problems and approach options Diabetes mellitus (LoE Ia, Grade A) HbA1c < 6.5% (below 48 mmol/mol) to reduce the risk of malformations Morning fasting glucose 5–7 mmol/L, 4–7 mmol/l preprandial [ 9 ] Chronic hypertension (LoE Ib, Grade A) Teratogenic risk due to antihypertensive drugs (ACE inhibitors, angiotensin receptor blockers); switch to pregnancy-compatible medication Examination for end organ damage: ventricular hypertrophy (ECG), retinopathy and kidney disease (proteinuria) in the case of long-standing, not well-controlled hypertension Switch to medication that has a better safety profile during pregnancy. examples for initial dosage: Methyldopa: 2–3 × 250 mg/d max. 2g/d Labetolol: 2 × 100 −200 mg/d, max 4 × 300mg/d Nifedipine retard: 30–60 mg/d, max. 120 mg/d Metoprolol 25–100mg/d max. 200 mg/d [ 89 ] Hypothyroidism (LoE IIa, Grade B) Hyperthyroidism (LoE IIb, Grade B) Psychiatric illnesses (LoE IIb, Grade B) Epilepsy [ 90 ] (LoE Ia, Grade A) Switch to lamotrigine, levetiracetam, carbamazepine Folic acid prophylaxis 5mg/d Avoidance of Valproate-containing preparations HIV (LoE Ia, Grade A) Thrombophilia (LoE Ia, Grade A) Complications during previous pregnancy (LoE IIb, Grade B) Hemoglobinopathy (LoE IIa, Grade B) Cardiovascular diseases, aortic diseases, pulmonary hypertension [ 95 ] (LoE IIa, Grade B) Multiple sclerosis [ 96 ] (LoE IIb, Grade B) Asthma [ 98 ] (LoE Ia, Grade A) Short-term β-agonists Long-term β-agonists (LABA—salmeterol, Inhaled corticosteroids (alone or in combination with LABA) Autoimmune rheumatic diseases [ 99 ], e.g., rheumatoid arthritis, spondyloarthritis, systemic lupus erythematosus, antiphospholipid AK, systemic sclerosis, mixed connective tissue) (LoE IIa, Grade B) Consultation and risk stratification; Adjustment to medication suitable for pregnancy, stable situation during 6–12 mo before pregnancy, check for anti Ro/SSA ± anti La/SSB, aPL profile (lupus anticoagulans, anti-Cardiolipin AK, anti b2 glycoproteins) no cyclophosphamide, methotrexate, thalidomide, mycofenolate mofetil Solid organ transplantation [ 100 ] (LoE IIb, Grade B) -Checking the kidney function -Assessment of the function of the transplanted organ (e.g., echocardiogram, lung function test -Determination of HLA antibodies -Upper abdominal sonography and liver function tests Patients should be vaccinated against influenza, pneumococci, varicella zoster, COVID 19 (hepatitis A/B, diphtheria, polio, pertussis and tetanus, optionally against meningococci and human papillomaviruses before a planned pregnancy [ 101 ] The teratogenic risk of oral and topical retinoids is well-known. It should be noted, however, that retinoids and products containing isotretinoin are becoming increasingly popular as “beauty products”. Some of the products are purchased via the internet in an uncontrolled manner, meaning that in individual cases the levels of active ingredients and thus teratogenic damage cannot be predicted. They are also not always prescribed according to a medical indication or by a doctor. Ideally, therefore, a patient should be warned about the use of retinoid-containing preparations or adequate contraception should be ensured [Grade D]. Inter-pregnancy interval : a short interval, especially < 12 months, is associated with unfavorable outcomes, including fetal growth restriction, preterm birth, neonatal morbidity and maternal morbidity, such as gestational diabetes and uterine rupture (after cesarean section) [ 102 ]. An interval of 1–2 years is recommended, although national guidelines vary [LoE IIa, Grade C]. Pre-eclampsia : The risk of pre-eclampsia in a subsequent pregnancy is around 15% and is very high (up to 50%) if the pre-eclampsia occurred before 28-week gestation (LoE IIa). In the long term, there is a three–fourfold risk of hypertension, coronary heart disease or cerebrovascular insults [ 89 ]. National societies like the German AWMF (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften) [ 89 ], ACOG (American College of Obstetricians and Gynecologists) [ 103 ] and NICE (National Institute for Health and Care Excellence) [ 104 ] recommend counseling and clarification, especially for women who have had pre-eclampsia before 34-week gestation or after a severe course; (Grade B) the corresponding recommendations regarding clarifications are listed in the respective guidelines. Of particular relevance is the exclusion of Antiphospholipid Syndrome, as this has therapeutic consequences for the next pregnancy (LoE IIb, Grade B). The AWMF guideline recommends prophylaxis with aspirin in a subsequent pregnancy if there are risk factors, or screening for pre-eclampsia according to the FMF UK algorithm [ 89 ]. Gestational diabetes : The greatest risk factor for the development of gestational diabetes (GDM) is GDM in the previous pregnancy; the risk is up to 48% in the subsequent pregnancy [ 30 ]. In women at high risk, early screening in the first trimester aims to detect previously undiagnosed overt diabetes and is, therefore, performed using fasting plasma glucose and/or HbA1c, rather than an oral glucose tolerance test (GTT). The GTT remains the diagnostic standard for routine gestational diabetes screening at 24–28-week gestation (LoE IIa, Grade B). Late miscarriage : Vaginal progesterone can potentially increase the probability of a live birth after a late miscarriage [ 105 ] (LoE III, Grade C). In recurring pregnancy loss, there is currently no consistent evidence [ 105 ] (LoE Ia, Grade B). Prophylactic cerclage after McDonald or Shirodkar in the next pregnancy should be discussed with the patient after late miscarriage or early preterm birth (“history-indicated”), as this can reduce the risk of preterm birth [ 106 , 107 ] (LoE Ia, Grade A). Recurrent pregnancy loss : Recurrent pregnancy loss (RPL) was first defined by the WHO in 1977 as three or more consecutive miscarriages before the 20th week of gestation [ 108 ]. More recent definitions by the WHO [ 109 ] and the ASRM [ 110 ] lowered this threshold to two consecutive losses. The 2017 guideline of the European Society of Human Reproduction and Embryology (ESHRE) further broadened the definition by including non-consecutive miscarriages and considering RPL present from two pregnancy losses onward [ 111 ] (LoE V). 1–3% of all couples suffer from three “recurrent” miscarriages, up to 5% suffer from two habitual miscarriages [ 112 ] (LoE IIb). Balanced chromosomal abnormalities are present in 2–5% of all couples with at least 2 miscarriages [ 112 ] (LoE IIb). The AWMF S2k guideline 2022 states that under special circumstances further investigations are granted after 2, in any case after 3 miscarriages [ 112 ] (LoE III–IV, Grade C). The diagnostic recommendations are outlined in the guideline; in brief, both partners should undergo genetic testing and an anatomical evaluation for uterine malformations. Endocrinological diagnostics for PCO and thyroid function testing should be performed [ 112 ] (LoE III–IV, Grade C). The data on the relationship between RPL and genetic thrombophilia is inconclusive; therefore, general coagulation testing is not recommended [ 112 ] (LOE IIa, Grade B). Aspirin and heparins should not be used as the sole prophylaxis for idiopathic RPL [ 112 ] (LoE Ia, Grade A). Although the incidence of antiphospholipid antibody syndrome (APS) is probably lower than previously thought, it is clinically relevant and should, therefore, be investigated; in the case of APS , prophylaxis with aspirin and low-dose low-molecular-weight heparin is recommended from early pregnancy on (LoE Ia, Grade A) (Table  3 ). Clinical and two laboratory tests at 12-week intervals are required to confirm the diagnosis: Table 3 Antiphospholipid antibody syndrome criteria—table according to [ 112 ] Clinical criteria Laboratory criteria  ≥ 1 venous or arterial thrombosis Anti-Cardiolipin—Ac (IgM, IgG) medium to high titers 1 or 2 unexplained miscarriages in morphologically unremarkable fetuses > 10 weeks' gestation Anti-ß2-glycoprotein-1-Ac (IgM, IgG) high titers  ≥ 3 abortions < 1 0th week of pregnancy Lupus anticoagulant  ≥ 1 late miscarriage or premature birth < 34 weeks' gestation due to placental insufficiency or pre-eclampsia Antiphospholipid antibody syndrome criteria—table according to [ 112 ] Further consultation in the event of abnormal findings and, if necessary, therapy should be carried out in a center or by a specialist with appropriate expertise. Fetal growth restriction : After a pregnancy with fetal growth restriction, the risk of recurrence is 20–30% [ 113 ] (LoE IIa). Pre-eclampsia screening as developed by the FMF (Fetal Medicine Foundation) should be performed in the subsequent pregnancy; if this is abnormal (i.e., uterine perfusion is impaired), prophylaxis with 100–150 mg aspirin should be given before 16 weeks of gestation to reduce the risk of recurrent growth restriction [ 113 ] (LoE Ia, Grade A). Late fetal demise : In addition to searching for the cause of intrauterine fetal death (IUFD), it may be important to reduce the risk before the next pregnancy occurs. Similar to the recommendations for recurrent pregnancy loss, screening for APS and thyroid function testing are recommended, while a general coagulation assessment is not [ 114 ] (LoE III, Grade C). Again, heparin and aspirin for general prevention of IUFD are not evidence-based, except in the case of APS (LoE Ia, Grade A). As with all pregnant women, FMF pre-eclampsia screening should be performed in the 1st trimester (LoE IIb, Grade B). Fetal malformation, chromosomal abnormalities or genetic conditions : Precise knowledge of a previous child’s condition is essential for counseling regarding a future pregnancy (LoE III). Interdisciplinary collaboration with pediatricians and medical genetics is recommended, and genetic counseling should always be offered before pregnancy (Grade C). With regard to prevention, a detailed medical history and, if necessary, folic acid prophylaxis should be considered (LoE III, Grade C). The risk of recurrence is highly dependent on the etiology; a so-called "mixed risk" of 5–9% is often cited if the etiology is unknown (LoE III, Grade C). In the case of a known genetic condition, both pre-implantation genetic testing and invasive prenatal testing (e.g., in the form of chorionic villus sampling at the end of the first trimester) may be possible (LoE IIb, Grade B). Previous preterm birth : The risk of recurrence after a spontaneous preterm birth is approx. 30%, and approx. 57% for ≥ 2 previous spontaneous preterm births < 32-week gestation [ 115 ] (LoE IIa). It is, therefore, important to reduce risk factors. While there is evidence for the use of vaginal progesterone in pregnancies with a short cervix after previous preterm birth, general use of vaginal progesterone without short cervix is not supported by current evidence [ 115 , 116 ]. The potential role of cervical cerclage as an alternative or adjunct to progesterone therapy should be discussed (LoE Ia, Grade A). Current evidence does not support the use of cervical pessaries, as multiple randomized controlled trials and meta-analyses could not show a benefit in different settings, including singleton and twin pregnancies with short cervix [ 117 – 120 ] Numerous guidelines, therefore, advise against the use of cervical pessaries for the prevention of preterm birth [ 121 , 122 ] (LoE Ia, Grade B). Genital malformation : Uterine malformations , genital septa, duplications or unilateral/asymmetric abnormalities are often asymptomatic, but are usually associated with early and late miscarriage, premature delivery and intrauterine growth retardation (LoE IIa). Surgical treatment in asymptomatic patients without miscarriages is not initially recommended, as many remain asymptomatic [ 123 ] (LoE III). The evidence for septal resection in cases of RPL with septate uterus is unclear; therefore, there is no recommendation for surgical management in the AWMF guideline in these cases [ 112 ] (LoE IIb–III, Grade C). Depending on their size and location (submucosal/intramural/submucosal), fibroids can have a negative impact on both fertility and the course of pregnancy. This also applies to initially asymptomatic fibroids (LoE IIa). Drug or surgical treatment prior to pregnancy is only recommended for symptomatic (menometrorrhagia, pain) or intracavitary fibroids and for submucosal fibroids with infertility or miscarriage [ 124 ] (LoE IIa, Grade B). Endometriosis is a possible cause of infertility and ectopic pregnancies. Symptomatic endometriosis should be diagnosed and treated independently of a current desire to have children [ 125 ]. Endometriosis has been associated with a higher risk of preterm birth in observational studies and meta-analyses, although the evidence is inconsistent (LoE IIb, Grade B). Gynecological infections and sexually transmitted diseases can lead to chronic pain and infertility, late miscarriage and preterm birth (bacterial vaginosis, aerobic vaginitis, abnormal vaginal flora) and long-term maternal and infant complications (Lues, HIV, hepatitis B and C). Screening should be considered as part of normal gynecological check-ups, especially in high-risk patients (LoE IIa, Grade B). Conization/cervical dysplasia : Since cervical dysplasia caused by HPV (human papilloma virus) infections disappears spontaneously, especially in younger women, and a history of conization (LEEP, i.e., Loop Electrosurgical Excision Procedure, knife, laser) is one of the important risk factors for preterm birth, it is particularly important that women who have not yet started/completed their family planning are not overtreated. HPV vaccination status should be routinely assessed [ 126 ] (LoE IIa, Grade A). Female genital mutilation and/or cutting (FGM/C) can lead to various obstetric problems and complications depending on the degree of severity or WHO classification type (LoE IIa). This should be discussed openly and in detail with the woman and her partner before pregnancy (Grade D). Consanguinity : Consanguinity increases the risk of having a child with a physical or mental disability to around 5–7% compared to the baseline risk [ 127 ] (LoE IIb). Consanguinity is a common practice depending on the region of the world, with a prevalence of up to (and over) 50% of all couples [ 128 ], so a three-generation pedigree or genetic counseling may be recommended if the cultural background is appropriate [ 127 ]. However, this fact alone should not be a reason for genetic testing. Genetic diseases, malformations, heart defects : If there are any conditions in the family history, the patient should be referred for genetic counseling if possible before a planned pregnancy, so that any risks can be identified with the patient and any necessary clarifications can be made. This aspect should also be discussed with the woman if she has a family history of cancers (e.g., BRCA 1/2 mutation) (LoE III, Grade C). Carrier status, carrier screening : Genetic testing is developing rapidly and some NIPT (non-invasive prenatal test) are already available to determine prenatal carrier status, i.e., whether a person carries a recessive genetic trait. It is particularly important to discuss the limits of this evolving technology (Grade D). Genetic counseling should be offered for familial genetic conditions (LoE III, Grade C). If there is a known (recessive) disease in the family or a known carrier status and genetic findings are available, it is usually possible to test family members with unknown carrier status for this variant before a planned pregnancy. Pre-eclampsia : A family history of pre-eclampsia is associated with a relative risk of around 3 for the development of pre-eclampsia and is, therefore, comparable to the risk of a multiple pregnancy or kidney disease in terms of risk factors [ 129 ] (LoE IIa, Grade B). Like all pregnant women, the patient should be made aware of the possibility of FMF pre-eclampsia screening and the reduction of modifiable risk factors, such as hypertension and BMI > 30 (LoE IIa, Grade B). α-, β-thalassemia, sickle cell anemia: If there is a corresponding family history and an ethnic group with an increased prevalence [ 130 – 133 ] (see below), testing for carrier status can be carried out, especially if the partner comes from the same cultural group [ 134 – 136 ] (LoE IIb, Grade B). The Canadian Society of Obstetrics and Gynecology states in its guideline: "From a pragmatic point of view, all patients who are not of Japanese, Korean, Caucasian or Northern European origin […] can be screened" [ 131 ] (LoE III—Guideline Consensus, Grade C) (Table  4 ). Table 4 Ethnic groups with a clinically relevant prevalence of hemoglobinopathies. Table according to [ 130 ] Hemoglobin S (sickle cell anemia) Africans including North Africans, African–Caribbean and any other African ethnicity (e.g., Central and South American) with partial African ethnicity, Greeks, southern Italians, including Sicilians, Turks, Arabs, Indians α 0 -Thalassemia Chinese, Taiwanese, Southeast Asia (Thai, Laotian, Cambodian, Vietnamese, Burmese, Malaysian, Singaporean, Indonesian, Philippines), Cypriots, Greeks, Turks and Sardinia β-Thalassemia All ethnic groups other than Northern Europeans Europeans Ethnic groups with a clinically relevant prevalence of hemoglobinopathies. Table according to [ 130 ] All ethnic groups other than Northern Europeans Europeans A first-line screening for hemoglobinopathies can consist of a full blood count with the respective indices, a hemoglobin analysis and iron parameters [ 131 ]. Pregnant women are potentially exposed to a variety of risks in the workplace: physical strain (e.g., heavy lifting), chemical substances (e.g., solvents), infectious agents and, in complex cases, psychosocial stress. The tolerable level, however, is strongly dependent on the social circumstances and national legislation. Gynecologists play a key role by discussing hazards on the basis of a personalized risk analysis and intervening in an advisory and, if necessary, protective capacity (Grade D). Psychosocial problems are often multifactorial and can also have a significant impact on the health of the pregnant woman and the child, both during pregnancy and postpartum. These include violence in partnerships, mental illnesses, such as depression and anxiety disorders, including PMDD (premenstrual dysphoric disorder), substance abuse (see above), but also financial precarity, isolation and the challenges of migration. Vulnerability due to the uncertainty of residence status and language barriers can put a strain on mental health and increase the risk of complications during pregnancy. Early identification of these risks and interdisciplinary support are crucial in order to protect the health of the mother and child in the best possible way [ 137 ] (LoE III, Grade C).

Preconception care offers a key opportunity to identify and modify risk factors before pregnancy, thereby improving maternal, fetal, and neonatal outcomes [ 1 , 2 ]. Many adverse pregnancy outcomes are linked to modifiable conditions or behaviors present prior to conception, such as chronic medical conditions, nutritional deficiencies, lifestyle factors, medication exposure, and infectious risks [ 3 ]. Despite growing evidence for effective preconception interventions, their implementation in routine clinical practice remains inconsistent [ 4 , 5 ]. The aim of preconception counseling, therefore, is the timely preparation of optimal conditions for pregnancy through the identification of risk constellations and the provision of targeted counseling to reduce maternal and child risks [ 5 ]. A growing body of literature on preconception care from various perspectives already addresses important aspects of the field, including a global framework by the World Health Organization (WHO) from 2012 [ 5 ] or recommendations by the International Federation of Gynecology and Obstetrics (FIGO) focused on domains, such as non-communicable diseases [ 6 ] or nutrition [ 7 , 8 ]. In the United Kingdom, the National Institute for Health and Care Excellence (NICE) addresses various preconception issues in different publications, such as the Guideline on Diabetes in Pregnancy [ 9 ], the guideline on Fertility Problems and the guideline on maternal and child nutrition [ 10 , 11 ]. The ACOG Committee Opinion on Prepregnancy Counseling [ 12 ] concisely summarizes key areas; it does so, however, within the U.S. healthcare context, and the Royal Australian College of General Practitioners also published an overview article about Preconception Care [ 4 ], focusing on primary care. All of the above-mentioned resources are valuable in their own context. They differ, however, in scope and purpose, ranging from public health strategies to selected clinical topics, and do not provide a consistently structured approach for routine clinical implementation. In addition, preconception care is often addressed in a fragmented manner across multiple documents rather than within a single integrated framework. This is exemplified in the NICE guidelines, where preconception care is covered across several documents rather than one unified, clinically oriented pathway, potentially limiting its clinical applicability. Consequently, there remains a lack of a clinically oriented guideline that consolidates the available evidence into a coherent and practical approach for everyday obstetric and gynecological care in the European healthcare context. This clinical practice guideline provides evidence-based, clinically applicable recommendations to support healthcare professionals in systematically identifying risks, optimizing maternal health and health-related knowledge, and planning necessary medical examinations and interventions sufficiently in advance of pregnancy. The scope of this guideline is the preconception period, defined as the time before conception in individuals of reproductive age who are planning a pregnancy or may become pregnant. It addresses medical, nutritional, lifestyle, infectious, and reproductive factors relevant to preconception counseling and care, while management during pregnancy and postpartum is only included where necessary for context. This guideline is intended for a broad clinical audience involved in reproductive healthcare, including obstetricians and gynecologists, general practitioners and midwives. By providing structured recommendations grounded in current evidence, this guideline seeks to promote consistent, high-quality preconception care across different healthcare settings.

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