The impact of surgical intervention on time to conception and obstetric outcomes in women with endometriomas: a retrospective cohort study

Background Endometriomas may adversely affect fertility; however, the necessity of its surgical management is a controversial subject. The aim of this study was to compare the time to conception, mode of conception, and pregnancy outcomes between two groups of patients diagnosed with endometriomas: those managed conservatively and those who laparoscopic cystectomy.

This retrospective study included patients diagnosed with endometriomas who are seeking pregnancy. All patients who conceived were categorized into the following two groups: those who underwent surgical intervention for treating endometriomas and those who did not. Demographic data, time to conception (months), and pregnancy outcomes were recorded.

A total of 5444 patients were screened, and data for 226 patients meeting the inclusion criteria were analyzed (80 in the surgical group and 146 in the nonsurgical group). Age and body mass index were comparable between the groups. Time to conception (months) was significantly different between the surgical and nonsurgical groups (24 [12–51] vs. 18 [6.5–36], p = 0.030). Further, the probability of conception over time was significantly higher in the nonsurgical group (p = 0.002). The live birth rate was 78.8% (n = 63) in the surgical group and 69.2% (n = 101) in the nonsurgical group, with no significant difference between the groups (p = 0.220).

Endometrioma surgery was associated with a longer time to conception but had no effect on live birth rate or delivery outcome. Patient selection is critical and further investigation is needed to determine who will benefit from surgery.

Endometrioma, Time to pregnancy, Fertility The impact of surgical intervention on time to conception and obstetric outcomes in women with endometriomas: a retrospective cohort study Halis Doğukan Özkan 1* , Merve Ayas Özkan2 , Ayşe Gizem Yıldız3 , Neval Çayönü Kahraman2 and Yaprak Engin-Üstün4 Page 2 of 10 Özkan et al. BMC Pregnancy and Childbirth (2025) 25:824

Endometriosis is defined as the presence of endome - trium-like tissue outside the uterine cavity. It is a chronic condition affecting approximately 10% of women of reproductive age [ 1]. Retrograde menstruation is con - sidered the most common potential cause for its patho - genesis [ 2]. The ovaries are the most commonly known location for the development of endometriosis, where it presents as an endometrioma. Endometriomas are found in 17–44% of patients with endometriosis and are con - sidered an indicator of advanced disease [ 3, 4]. Endome- triomas can impair fertility; however, they do not always cause infertility [5]. There is no consensus on the optimal management strategy for endometriomas in patients planning preg - nancy. Depending on the patients’ symptoms and clinical presentations, endometriomas may be managed conser - vatively or surgically [ 5]. However, surgical treatment carry potential risks, such as reduced ovarian reserve [ 6]. Some studies have suggested that surgical treatment of endometriomas may improve spontaneous conception rates [ 7, 8]. According to the revised American Society for Reproductive Medicine (rASRM) guidelines, opera - tive laparoscopic surgery may enhance the likelihood of successful conception in patients with stage 1–2 endome- triosis [9, 10]. Surgical intervention remains a controver - sial alternative in patients with endometriosis due to the uncertainty of the balance between the risk of reduced ovarian reserve and the possibility of a favorable impact on pregnancy by the reduction in levels of inflamma - tory factors [ 11, 12]. Because of this uncertainty, surgery is often recommended for patients with considerable symptoms, such as pain or mass effect, that compromise their quality of life [ 5, 12]. Among surgical options, lapa - roscopic cyst excision is preferred over other techniques, as it is associated with a lower risk of recurrence [ 13– 16] and higher pregnancy rates [13, 14, 16]. Several studies have compared pregnancy rates and outcomes between patients with endometriomas who are treated conservatively and those treated surgically. The achievement of pregnancy and the time to conception are crucial in women desiring pregnancy. Time to concep - tion is also a critical clinical parameter for clinicians to provide appropriate counseling and plan individualized treatment strategies. Although previous studies [ 17, 18] have evaluated time to conception following different surgical techniques for endometriomas, to our knowl - edge, no study has directly compared time to conception between surgically and nonsurgically managed patients. The aim of this study was to compare the time to con - ception, mode of conception, and pregnancy outcomes between the patients with endometriomas who were managed conservatively and those who underwent surgi - cal intervention.

Sample collection This retrospective cohort study was conducted between January 2014 and December 2023 at the Ankara Etlik Zübeyde Hanım Gynecology and Obstetrics Training and Research Hospital among women diagnosed with endometriomas who subsequently conceived. This hos - pital is one of Turkey’s most specialized women’s health and obstetrics centers, with approximately 15,000 births annually. Ethical approval for the study was obtained from the Etlik Zübeyde Hanım Training and Research Hospital Ethics Committee (decision number 2024/12, dated 09.10.2024). The study was conducted in accor - dance with the Declaration of Helsinki. Patients who wished to conceive and who visited for routine preconceptional gynecologic examinations were considered for the study. The patients selected for the study were those diagnosed with endometriomas dur - ing routine examinations and actively planning preg - nancy. A total of 226 patients aged 18–35 years who were diagnosed with endometriomas, continued unprotected intercourse without interrupting the conception process, and eventually became pregnant were included in the study. All patients who met the inclusion and exclusion criteria were consecutively enrolled during the specified study period. Patients with infertility; who interrupted pregnancy planning; or underwent laparotomic sur - gery, laparoscopic ablation, or drainage were excluded. Patients with severe systemic disease and incomplete medical records were also excluded. Further, patients with an antral follicle count (AFC) < 5 at the first pre- pregnancy evaluation (during the ultrasound at the time of endometrioma diagnosis) were excluded. In our clinic, the AFC count is routinely examined at the first precon - ceptional visit. The AFC limit was selected according to European Society of Human Reproduction and Embryol - ogy (ESHRE) guidelines [19]. Patients who were planning pregnancy and were diag - nosed with endometriomas during routine preconception examinations were included, based on the study criteria stated above (n = 226). Group 1 consisted of patients who were managed conservatively without planned surgery and subsequently conceived (nonsurgical group, n = 146). Group 2 included patients who underwent surgical inter - vention for endometriomas and later conceived (surgical group, n = 80). Diagnosis was confirmed through histo - pathological examination in the surgical group. In the nonsurgical group, transvaginal ultrasonography served as the principal imaging technique for diagnosis. Mag - netic resonance imaging (MRI) was conducted selectively at instances when the ultrasound results were incon - clusive. Diagnostic criteria included low-level internal echoes, multilocular cystic structures, and hyperechoic foci within the cyst wall [ 20, 21]. Only patients who Page 3 of 10 Özkan et al. BMC Pregnancy and Childbirth (2025) 25:824 underwent laparoscopic cystectomy were included in the surgical group. All surgical procedures were planned and performed by experienced surgeons specializing in endo - metrioma and infertility. Only patients actively attempt - ing to conceive were selected. For both groups, maternal demographic characteris - tics, obstetric history, preconception body mass index (BMI), cancer antigen-125 (CA-125) levels (U/mL), endometrioma ultrasound findings, time to conception (months) after diagnosis or surgery, mode of concep - tion, gestational age at delivery, mode of delivery, and pregnancy complications in viable pregnancies were recorded. Time to conception was measured from the first medical consultation for pregnancy planning in the nonsurgical group. In the surgical group, it was measured beginning from two menstrual cycles after surgery (the recommended contraception period). In clinical prac - tice, patients are advised to avoid pregnancy for two menstrual cycles after surgery to allow adequate heal - ing and recovery. Therefore, in the surgical group, time to conception was measured beginning from two men - strual cycles after surgery. Pregnancy complications recorded were placenta previa, gestational hypertension, gestational diabetes mellitus, multiple pregnancy, intra - hepatic cholestasis of pregnancy, polyhydramnios, oligo - hydramnios, fetal growth retardation, premature rupture of membranes, preterm premature rupture of mem - branes, and postpartum neonatal death. As the number of cases was not adequate for comprehensive analysis of individual complications, pregnancy complications were combined and statistically compared between the two groups (presence and absence of any complication). Demographic data, maternal obstetric history, and other parameters were retrospectively obtained from the hos - pital records. Statistical analysis Data analysis was performed using Jamovi version 2.3.38 (www.jamovi.org) and Python version 3.11. The normal - ity of continuous variables was assessed using the Sha - piro-Wilk test, histograms, and Q–Q plots. Continuous variables were presented as mean ± standard deviation or median with interquartile range (25th–75th percen - tile), depending on the distribution. Categorical variables were summarized as counts and percentages. The Mann- Whitney U test was used to compare continuous vari - ables between the two groups. The Chi-square (χ2) test was applied to compare categorical variables. Kaplan– Meier analysis and survival curves were used to visualize the time to conception between surgical and non-surgi - cal groups. Since all participants eventually conceived, no censoring was applied in the Kaplan–Meier analysis. The log-rank test was used to compare survival curves between the groups. A multivariate linear regression analysis was conducted to evaluate the impact of poten - tial predictors on time to conception (in months). The independent variables included age, gravida, parity, pre- pregnancy BMI, cyst size measured by ultrasound, use of ART, and surgical treatment for endometrioma. The

of the regression analysis were reported as coef - ficients (β) with corresponding standard errors, t-values, and p-values. A p-value of < 0.05 was considered statis - tically significant unless otherwise specified. There were no missing data for the variables analyzed in this study; thus, no imputation methods were required.

During the study period, a total of 226 patients with endometriomas who met the inclusion criteria and con - ceived were included in the analysis. Of these, 80 patients who underwent laparoscopic surgery comprised the sur - gical group, and 146 patients who were managed con - servatively comprised the nonsurgical group. The study flowchart (Fig. 1) provides details of the patient selection process. A total of, 226 patients were included in the study. The median age of the patients who participated in the study was 26 years (23–29). The median gravida was 1 (1, 2), and the median pre-pregnancy BMI was 24 (22–27). Of the patients, 146 had not undergone surgery, whereas 80 had undergone surgery due to endometrioma. A total of 75.7% of the patients conceived spontaneously. The median time to conception was 24 (8–48) months. Among the patients, 164 (72.1%) had live births, whereas 62 (27.9%) pregnancies did not reach viability. Other patient characteristics are summarized in Table 1. When the surgical and nonsurgical groups were com - pared, the median age was 26 years (23–30) in the surgi - cal group and 26 years (22–28) in the nonsurgical group, with no statistically significant difference ( p = 0.146). Similarly, the median BMI was 25 (22–28) in the surgical group and 24 (22–26) in the nonsurgical group. The BMI was not significantly different between groups (p = 0.335). However, median gravida was 1 (1, 2) in the surgical group compared to 1 (1, 1) in the nonsurgical group. Median gravida was significantly higher in the surgi - cal group ( p = 0.040). The median parity was 1 (0–2) in the surgical group and 0 (0–1) in the nonsurgical group. Median parity was significantly lower in the surgical group (p = 0.003). History of Cesarean section (CS) was 0 (0–0) in the nonsurgical group and 0 (0–1) in the surgical group. History of CS was significantly higher in the surgi- cal group ( p = 0.005). In the surgical group, 28.7% of the women and in the nonsurgical group, 13.0% had a his - tory of previous CS, indicating that not all CS deliveries observed in this study were primary procedures. Other characteristics of the groups are summarized in Table 2. Page 4 of 10 Özkan et al. BMC Pregnancy and Childbirth (2025) 25:824 The distribution of cyst sizes according to surgical management is presented in Table  3. The proportion of patients with cysts > 4  cm was significantly higher in the surgical group (87.5%) than in the nonsurgical group (64.4%) ( p = 0.001; OR: 3.87, 95% CI: 1.84–8.16). Although the proportion of patients with cysts > 4 cm was significantly higher in the surgical group, the majority of patients (57.3%) with cysts > 4 cm were managed conser - vatively. The median time to conception was 24 (12–51) in the surgical group and 18 (6.5–36) in the nonsurgical group. The median time to conception was significantly longer in the surgical group than in the nonsurgical group (p = 0.030). The number of live births was 63 (78.8%) in the surgical group and 101 (69.2%) in the nonsurgical group, with no significant difference between the groups (p = 0.220; OR: 1.76, 95% CI: 0.95–3.27). No significant differences were observed between the groups in terms of term/preterm delivery (OR: 0.45, 95% CI: 0.17–1.21), pregnancy complications (OR: 0.70, 95% CI: 0.35–1.42), mode of delivery (OR: 1.13, 95% CI: 0.59–2.14), or mode of conception (OR: 1.76, 95% CI: 0.95–3.27). These data are presented in Table 3. Kaplan–Meier survival analysis was used to assess the probability of conception over time. The cumulative probability of conception was significantly higher in the nonsurgical group than in the surgical group (Log-rank test, p = 0.002) (Fig. 2). As all patients in the study eventu- ally conceived, no censoring was applied in the Kaplan– Meier analysis. A multivariate linear regression analysis was per - formed to identify factors influencing the time to con - ception in women with endometriomas (Table  4; Fig.  3). The analysis indicated that undergoing surgical treat - ment for endometrioma significantly prolonged the time to conception by approximately 14 months (β = 14.027, p = 0.002). Age, gravida, parity, pre-pregnancy BMI, cyst size, and ART usage did not show statistically significant associations with the time to conception. The overall regression model was statistically significant (F = 2.946, p = 0.006) and explained 5.7% (adjusted R² = 0.057) of the variance in time to conception. A forest plot (Fig.  3) was created to visually represent the regression coefficients and 95% confidence intervals for the variables included in the multivariate linear regression analysis.

The aim of the present study was to evaluate whether surgical treatment affects the time to conception, mode of conception, pregnancy outcomes, and mode and time of delivery in patients with endometriomas. The primary Fig. 1 Flowchart of the patient selection Page 5 of 10 Özkan et al. BMC Pregnancy and Childbirth (2025) 25:824 finding of the study was that the time to conception was longer in the group of patients who underwent surgery for endometriomas than that in the patients who did not undergo surgery. In contrast, no significant differences were observed between the surgical and nonsurgical groups with respect to mode of conception, pregnancy outcomes, mode of delivery, or timing of delivery. This suggests that while surgical treatment may prolong the time to conception, it does not impact overall preg - nancy outcomes after conception. To our knowledge, few studies have investigated time to conception in patients with endometriomas [ 17, 18], and these studies have directly compared surgical and nonsurgical manage - ment approaches. These findings highlight the need for Table 1 Demographic, laboratory, and other characteristics of the patients Age (years), median (IQR 25-75) 26 (23-29) Gravida, median (IQR 25-75) 1 (0-2) Parity, median (IQR 25-75) 0 (0-1) History of NVD, median (IQR 25-75) 0 (0-1) History of CS, median (IQR 25-75) 0 (0-0) Pre-pregnancy BMI (kg/m2), median (IQR 25-75) 24 (22-27) CA-125, median (IQR 25-75) 39.0 (18.8-82.6) Ultrasound Findings, n (%) Group1 ( 4 cm) 164 (72.6) Endometrioma Surgery, n (%) Non-surgical 146 (64.6) Surgical 80 (35.4) Time to conception (month), median (IQR 25-75) 24 (8-48) Mode of conception n (%) Spontaneous 171 (75.7) Intrauterin inseminastion 16 (7.1) In vitro fertilization 39 (17.2) Pregnancy complications n (%) Absent 115 (50.9) Present 49 (21.7) Abortion 62 (27.4) Pregnancy outcome n (%) Live birth 164 (72.6) Abortion 62 (27.4) Time of delivery n (%) Term birth 139 (61.5) Preterm birth 25 (11.1) Abortion 62 (27.4) Mode of delivery, n (%) NVD 68 (30.1) CS 96 (42.5) Abortion 62 (27.4) IQR Interquartilerange, NVD Normal vaginal delivery, CS Cesarean Section, BMI Body mass index, C A-125 Cancer antigen 125 Table 2 Comparison of demographic characteristics between surgical and Non-Surgical groups Non-surgical group Surgical group p Age (years) Median (IQR 25–75) 26 (23–30) 26 (22–28) 0.146 Gravida Median (IQR 25–75) 1 (0–1) 1 (0–2) 0.040 Parity Median (IQR 25–75) 0 (0–1) 1 (0–2) 0.003 History of NVD Median (IQR 25–75) 0 (0–1) 0 (0–1) 0.314 History of CS Median (IQR 25–75) 0 (0–0) 0 (0–1) 0.005 Pre-pregnancy BMI Median (IQR 25–75) 24 (22–26) 25 (22–28) 0.335 IQR Interquartilerange, NVD Normal vaginal delivery, CS Cesarean Section, BMI Body mass index Table 3 Comparison of ultrasound findings, pregnancy outcomes, and laboratory results between surgical and non- surgical groups Non- surgical group Surgical group p OR (95% Confi- dence Interval) Ultrasound Findings, n (%) 0.001 3.87 (1.84- 8.15) Group1 ( 4 cm) 94 (64.4) 70 (87.5) Mode of conception, n (%) 0.073 1.76 (0.95- 3.27) Spontaneous 116 (79.5) 55 (68.8) ART 30 25 Intrauterin inseminastion 11 (7.5) 5 (6.2) In vitro fertilization 19 (13) 20 (25) Pregnancy outcome, n (%) 0.220 0.61 (0.32- 1.15) Live birth 101 (69.2) 63 (78.8) Abortion 45 (30.8) 17 (21.2) Time of delivery (Live births only), n (%) 0.107 0.45 (0.17- 1.21) Term birth 82 (81.2) 57 (90.5) Preterm birth 19 (18.8) 6 (9.5) Pregnancy complica- tions (Live births only), n (%) 0.322 0.70 (0.35- 1.42) Absent 68 (67.3) 47 (74.6) Present 33 (32.7) 16 (25.4) Mode of Delivery (Live births only), n (%) 0.715 1.13 (0.59- 2.14) NVD 43 (42.6) 25 (39.7) CS 58 (57.4) 38 (60.3) Time to conception (month), median (IQR 25-75) 18 (6-36) 24 (12-57) 0.030 - CA-125 (U/ml), median (IQR 25-75) 39 (18-83) 39.5 (20-74.8) 0.973 - OR Odds ratio, IQR Interquartilerange, NVD Normal vaginal delivery, CS Ceserian section, C A-125 Cancer antigen 125 Page 6 of 10 Özkan et al. BMC Pregnancy and Childbirth (2025) 25:824 individualised decision-making regarding surgery in endometrioma patients planning pregnancy. Hemmings et al. (1998) compared different surgi - cal techniques in the treatment of endometrioma and reported that the time to first pregnancy was shorter in patients who underwent laparoscopic fenestration and coagulation compared to that in patients who under - went cystectomy [17]. However, all patients in their study underwent surgical treatment. Further, data regarding infertility history of the patients included the study were insufficient. Surgical techniques and clinical decision- making have also advanced significantly since 1998; hence, the capacity of the study to reflect current clinical practice is limited. Similar to this study, Roman et al. [18] conducted a retrospective review of patients undergo - ing ablation using plasma energy surgery in a study of 55 patients and did not use a control group. In their study, 42% patients had a history of infertility. They empha - sized that 33 patients wanted pregnancy and 22 patients became pregnant, and reported that the mean time from surgery to first pregnancy was 7.6 months in patients who conceived. Our study aims to bridge a different gap in clinical literature by directly comparing time to con - ception and pregnancy outcomes between patients who underwent surgical or conservative treatment in newly Table 4 Multivariate linear regression analysis of factors affecting time to conception Variable Coeffi- cient (β) Stan- dard Error t-value p- value Constant 40.352 15.449 2.612 0.010 Age (years) −0.609 0.397 −1.534 0.127 Gravida (n) −3.393 2.745 −1.236 0.218 Parity (n) −1.089 3.647 −0.299 0.766 Pre-pregnancy BMI (kg/ m²) 0.255 0.504 0.505 0.614 Cyst size (cm, by ultrasound) −0.291 0.998 −0.291 0.771 ART usage −3.870 4.675 −0.828 0.409 Surgical treatment 14.027 4.376 3.206 0.002 Fig. 2 Changing probability of conception over time in surgical and non-surgical groups Page 7 of 10 Özkan et al. BMC Pregnancy and Childbirth (2025) 25:824 diagnosed patients with no history of infertility and planning pregnancy. Recent studies have shown that laparoscopic cystectomy may increase the likelihood of spontaneous conception compared to laparotomy and that cystectomy is associated with lower endometrioma recurrence compared to other laparoscopic techniques. This may be considered as a reason for an increase in the likelihood of spontaneous conception [13, 22– 24]. In contrast, studies evaluating patients with endo - metriomas undergoing in vitro fertilization (IVF) have reported conflicting results regarding oocyte quality, anti-Müllerian hormone (AMH) levels, fertilization rates, and pregnancy outcomes after cystectomy [ 5, 25– 27]. Some studies have shown that AFC remains unchanged after endometrioma surgery. No significant difference was observed between AFC measured before and after surgery [28, 29]. Conversely, a large-scale study reported that cystectomy may reduce ovarian reserve (as indicated by AFC and AMH levels) and pregnancy rates in the long term [30]. These conflicting results may be attributed to differences in surgeon experience and surgical techniques used. Furthermore, these results could be attributed to differences in the age, infertility history, and baseline AMH and AFC values of the selected patients. Only patients who underwent laparoscopic cystectomy were included in this study and patients who underwent lapa - rotomy or alternative techniques such as aspiration and coagulation were excluded. The surgical group comprised patients with a relatively high pregnancy potential. The patients were young, had no history of infertility, actively desired pregnancy, and had a normal AFC count on routine pre-pregnancy examination. Despite these characteristics, the time to conception was found to be shorter in the nonsurgical group ( p = 0.030). Kaplan– Meier analysis and the Log-rank test results showed that the nonsurgical group had a higher conception rate per monthly interval than the surgical group ( p = 0.002). Fur- thermore, multivariate linear regression analysis showed that endometrioma surgery was independently linked to a notably longer time to conception (β = 14.0, p = 0.002). This finding suggests that patients with endometriomas who undergo conservative treatment may have a higher potential to conceive in the long term. This advantage observed in the nonsurgical group may be attributed to the preservation of ovarian reserve and the prevention of potential adverse effects associated with surgery. One of the possible mechanisms underlying the lon - ger time to conception in the surgical group may involve direct surgical trauma to the ovarian cortex and a reduc - tion in ovarian reserve due to the loss of healthy follicu - lar tissue during cystectomy. Additionally, postoperative inflammation and the development of intra-abdominal adhesions may disrupt the tubo-ovarian association, potentially affecting fertility. Further, adhesions caused by endometrioma can impair the anatomical relation - ship between the fallopian tube and ovary, resulting in Fig. 3 Forest plot of multivariate linear regression analysis: factors influencing time to conception Page 8 of 10 Özkan et al. BMC Pregnancy and Childbirth (2025) 25:824 infertility. Some studies have reported an increase in pregnancy rates following adhesiolysis for treating endo - metrioma [ 31]. Although reaching a consensus on this issue is difficult, our findings suggest that conservative management of patients recently-diagnosed with endo - metriomas who do not have a history of infertility and are planning pregnancy may result in more favorable results in selected patient groups. Live birth rates in patients who underwent surgery have been compared to those in patients who did not. A meta-analysis by Wu et al. including 13 studies found no significant difference in live birth and pregnancy rates between patients treated surgically and those treated conservatively (OR: 0.83, 95% CI: 0.56–1.22) [ 8]. Simi - larly, large meta-analyses by Hamdan et al. and Nickkho- Amiry et al. found no significant difference in live birth and pregnancy rates between surgical and nonsurgical patients (OR: 0.90, 95% CI: 0.63–1.28; OR: 0.75, 95% CI: 0.54–1.06, respectively) [ 32, 33]. Hosseinimousa et al. also showed that laparoscopic cystectomy did not affect live birth rates (OR: 1.08, (95% CI 0.51–22.77)) [ 34]. Shi et al. argued that the adverse effects of endometriosis on pregnancy outcomes may be mitigated following laparo - scopic surgery, and showed an increase in clinical preg - nancy rates in the surgically treated group [ 35]. However, in the study by Shi et al., the surgical group had a lower BMI and consisted of younger patients, which may have contributed to the observed differences. In this study, age and BMI were similar between the groups, and no signifi- cant difference was found in live birth rates between the surgical and nonsurgical groups (OR: 0.61, 95% CI: 0.32– 1.15; p = 0.220). An increased risk of pregnancy and fetal complica - tions in patients with endometriosis has been highlighted by several studies. Adverse pregnancy outcomes such as preterm labor, preeclampsia, fetal growth restriction, placenta previa, placental abruption, postpartum hem - orrhage and stillbirth have been reported [ 36– 39]. In the present study, both groups comprised patients with endometriomas. We compared pregnancy complications between the surgical and nonsurgical groups because the number of cases with complications was not adequate for statistical comparison. As such, the study may not have sufficient statistical power to detect significant dif - ferences in rare pregnancy outcomes. No significant dif - ferences were observed between the two groups in terms of overall complications (OR: 0.70, 95% CI: 0.35–1.42; p = 0.322). In patients planning pregnancy, the size of endo - metrioma cysts is one of the key parameters influenc - ing the decision for surgical intervention. However, larger cysts pose a greater risk of damage to ovarian tis - sue during surgery, which may result in a reduction in ovarian reserve [ 14, 40]. According to the 2022 ESHRE guidelines, cyst size alone is not a sufficient indication for surgery; the decision should also take into account other symptoms [5]. rASRM reports that laparoscopy increases live birth rates in patients with stage 1–2 disease; how - ever, routine surgery is not recommended as its benefits are uncertain [ 5, 32]. In this study, the surgical group predominantly comprised patients having cysts of ≥ 4 cm (p 4 cm was similar between the surgical and nonsurgical groups. Notably, the num - ber was higher in the nonsurgical group (70 (42.7%) vs. 94 (57.3%), respectively). This suggests that cyst size may have influenced the decision for surgery; however, it was not the only determinant and that other clinical factors contributed to the treatment approach in the patients included in the study. The timing and mode of delivery differ between preg - nant patients diagnosed with endometriomas and healthy pregnant women. Women with endometriomas have higher rates of cesarean section and an increased risk of preterm birth [ 34, 41]. In the present study, all patients were diagnosed with endometriomas. Further, 30% patients had a vaginal delivery, 42.5% underwent cesar - ean section, and 27.4% experienced pregnancy loss before viability. There was no significant difference between the surgical and nonsurgical groups in terms of mode of delivery (OR: 1.13, 95% CI 0.59–2.14; p = 0.715). Regard- ing the time of delivery, the majority of the patients in both groups delivered at term. There was no statistically significant difference between the groups in terms time of delivery (OR: 0.45, 95% CI 0.17–1.21; p = 0.107). This study had a retrospective design and was con - ducted using data from a single center. This may limit the generalizability of the findings to different popula - tions. Although our study was limited to a single tertiary care center, our findings are consistent with previous large-scale meta-analyses, suggesting that the results can be generalized to similar populations in other settings. AMH levels were not available for all patients, and there - fore, were not included in the analysis, which is another

of our study. Although baseline AMH levels were not available for the study population, all patients included in the study had an AFC above 5 at their first preconception assessment, minimizing the possibility of severe baseline ovarian reserve deficiency. Furthermore, because our study included both surgical and nonsurgi - cal patients, a standardized classification of endome - triosis severity (such as the rASRM score) could not be uniformly applied, which may limit our ability to account for disease severity as a confounding factor. Furthermore, although endometrioma was diagnosed using ultrasound and MRI findings in the nonsurgical group, the lack of pathologic confirmation represents another limitation of Page 9 of 10 Özkan et al. BMC Pregnancy and Childbirth (2025) 25:824 the study. Moreover, subgroup analyses based on mode of conception (spontaneous vs. ART) were not included. Future studies focusing on this issue may provide valu - able insights into treatment choice. Despite these limitations, the primary strength of this study lies in its focus on a cohort consisting predomi - nantly of patients who conceived spontaneously. Most studies in the literature investigating endometrioma and pregnancy outcomes have been designed in populations undergoing IVF or intracytoplasmic sperm injection (ICSI). In contrast, 75.8% of the patients in this study conceived spontaneously.

This study aims to elucidate an area that has not been adequately addressed in the literature by comparing time to conception and pregnancy outcomes between patients with endometriomas with and without surgery. Our find- ings suggest that surgery prolongs the time to conception in patients with endometriomas; however, surgery does not influence the mode of conception, intrapartum preg - nancy outcomes, mode of delivery, or timing of delivery. In the light of our findings, conservative approach can be considered as one of the first treatment choice in newly diagnosed patients with endometriomas who have no history of infertility and planning pregnancy. The earlier time to conception observed in the nonsurgical group suggests the importance of a more careful and individu - alized approach to the surgical decision. Clinical deci - sion-making should take into account individual patient characteristics such as ovarian reserve, severity of disease and symptoms, and pregnancy plan to guide the need for surgical intervention in women with endometriomas. Further prospective studies, especially randomized con - trolled trials, are needed to validate the findings of this retrospective study. Abbreviations AFC Antral follicle count ESHRE European Society of Human Reproduction and Embryology IVF In vitro fertilization ICSI Intracytoplasmic sperm injection MRI Magnetic Resonance Imaging rASRM Revised American Society for Reproductive Medicine BMI Body Mass Index

We thank all the participating patients for their generous contributions to this study. Authors' contributions HDO, MAO, NÇK and YYU contributed to the concept and design of the study. MAO, NCK performed the statistical analyses. HDO and MO drafted the first version of the manuscript. MAO, HDO, AGY, NCK were involved in analyzing and interpreting the data. HDO, MAO contributed to interpreting the data, and gave critical feedback throughout the preparation of manuscript. YYU critically reviewed the manuscript, and all authors gave approval for the final version of the manuscript. Funding No Funding. Data availability The data that support the findings of this study are not openly available due to reasons of sensitivity. If requested, data can be shared by the corresponding author with patient names and ID’s anonymized. Declarations Ethics approval and consent to participate Ethical approval for the study was obtained from the Etlik Zübeyde Hanım Training and Research Hospital Ethics Committee (decision number 2024/12, dated 09.10.2024). The requirement for informed consent to participate was waived by the same Ethics Committee due to the retrospective nature of the study. The study was conducted in accordance with the Declaration of Helsinki. Consent for publication Not Applicable. Competing interests The authors declare no competing interests. Received: 8 February 2025 / Accepted: 23 July 2025

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