Preoperative Anemia and Perioperative Outcomes in Gynecological Surgery: A Single-Center Retrospective Study.

The incidence of preoperative anemia in gynecological inpatients ranges from 24–45%, 1 , 2 diseases like endometrial polyps, gynecological malignancy, uterine leiomyoma and adenomyosis are the common causes. The diagnostic threshold for anemia is related to age, gender and ethnicity. A statistical analysis incorporating 18 individual datasets from 8 countries (China involved) revealed that, in non-pregnant females aged 18–65 years, the fifth centile was 119.7 g/L. 3 This was essentially consistent with the World Health Organization (WHO) criteria. 4 Therefore, using 120g/L as the diagnostic threshold for anemia was reasonable. Even mild, preoperative anemia is associated with increased risk of perioperative transfusion and increased morbidity (such as infection, thromboembolic events and intestinal obstruction) and mortality after surgery. 5–10 It can also affect patients’ recovery, prolong length of stay (LOS) and increase hospitalization costs. 2 , 5 , 8 In view of these adverse effects, the International Consensus Conference on Patient Blood Management (PBM) in Frankfurt in 2018 strongly recommended timely identification and appropriate management of anemia before major elective surgery. 11 The most common interventions included restrictive red blood cell (RBC) transfusion, using pharmacologic hemostatic agents and iron therapy. To promote and implement PBM, Chinese clinicians also published the Expert Consensus on Perioperative Blood Management in Gynecological Patients in 2019. 12 However, a national cross-sectional study to assess the prevalence and intervention of preoperative anemia conducted in 2021 showed that, the overall prevalence of preoperative anemia in China was 27.57%, but the intervention rate was only 12.57%. 13 It indicated that preoperative anemia was a relatively common issue in China that had not been fully appreciated. This might lead to unnecessary blood transfusion and increase the risk of perioperative complication. Furthermore, previous literatures on preoperative anemia in gynecology has mostly focused on elective major surgery or malignant tumor surgery. Comprehensive data on preoperative anemia in gynecological surgeries remained scarce, particularly within the Chinese population. Therefore, our center conducted a single-center, retrospective study to investigate the incidence of preoperative anemia and its impact on perioperative outcomes, including perioperative complication, perioperative RBC transfusion, hospitalization costs and LOS.

A total of 2519 patients was included in this study with the median age of 46 years (IQR, 38–56 years). The incidence of preoperative anemia was 30.8% (776/2519), among which 44.4% were mild anemia, 48.0% were moderate anemia, 7.4% were severe anemia. Table 1 presented the patients’ basic characteristics, including age, BMI, comorbidity, diagnostic category, surgery grade, surgery duration and volume of blood loss during surgery. Table 1 Patients’ Characteristics Anemic (N = 776) Non-Anemic (N = 1743) P Age, years 44 (37, 52) 47 (38, 58) <0.001 BMI, kg/m 2 23.2 (20.9, 25.5) 23.9 (21.8, 26.6) <0.001 Comorbidity 201 (25.9) 551 (31.6) 0.002 Diagnostic Category <0.001  Endometrial/cervical polyp 151 (19.5) 340 (19.5)  Vaginal bleeding 71 (9.1) 128 (7.3)  Uterine leiomyoma 145 (18.7) 200 (11.5)  Adenomyosis 20 (2.6) 24 (1.4)  Benign ovarian tumor 117 (15.1) 333 (19.1)  Pelvic floor dysfunction 43 (5.5) 226 (13.0)  Precancerous lesions 77 (9.9) 206 (11.8)  Gynecological malignancy 86 (11.1) 166 (9.5)  Others 66 (8.5) 120 (6.9) Surgery grade 0.196  Grade 1 15 (1.9) 18 (1.0)  Grade 2 327 (42.1) 767 (44.0)  Grade 3 224 (28.9) 469 (26.9)  Grade 4 210 (27.1) 489 (28.1) Surgery duration, minute 62 (20, 115) 57 (20, 105) 0.056 Volume of blood loss, mL 20 (5, 100) 10 (5, 50) 0.015 Notes : Mann–Whitney U -test for continuous variables, χ² -test for categorical variables.Medians (IQR) for continuous variables, frequencies (%) for categorical variables. Abbreviations : BMI, body mass index; IQR, interquartile range. Patients’ Characteristics Notes : Mann–Whitney U -test for continuous variables, χ² -test for categorical variables.Medians (IQR) for continuous variables, frequencies (%) for categorical variables. Abbreviations : BMI, body mass index; IQR, interquartile range. In total inpatients, compared with non-anemic group, anemic group had younger age (44 vs 47, P < 0.001), lower BMI (23.2 vs 23.9, P < 0.001) and lower proportion of having comorbidity (25.9% vs 31.6%, P = 0.002) ( Table 1 ); however, it displayed higher incidences of perioperative RBC transfusion (10.7% vs 1.7%, P < 0.001) and complication (4.4% vs 0.9%, P < 0.001), higher hospitalization costs (14531 vs 13681, P = 0.044) and longer LOS (6 vs 5, P < 0.001) ( Table 2 ). The confounding variables identified through univariate regression analysis included age, BMI, comorbidity, gynecological malignancy, surgery duration, and volume of blood loss. After adjusting for confounding variables, lower BMI (aOR = 0.893, P = 0.016), having comorbidity (aOR = 4.422, P < 0.001), preoperative anemia (OR = 6.259, P < 0.001), gynecological malignancy (aOR = 4.376, P < 0.001), longer surgery duration (aOR = 1.010, P < 0.001) and greater volume of blood loss (aOR = 1.002, P < 0.001) were associated with higher incidences of perioperative complication. In addition, lower BMI (aOR = 0.924, P = 0.023), having comorbidity (aOR = 2.702, P < 0.001), preoperative anemia (OR = 15.932, P < 0.001), longer surgery duration (aOR = 1.006, P = 0.003) and greater volume of blood loss (aOR = 1.006, P 0.05), with the prediction rate exceeding 90%. Table 2 Comparison Between Anemic and Non-Anemic Groups in Total Inpatients Anemic (N = 776) Non-Anemic (N = 1743) P Perioperative transfusion 83 (10.7) 29 (1.7) <0.001  Preoperative transfusion 33 (4.3) 0 (0.0)  Intra/post-operative transfusion 66 (8.5) 29 (1.7) Perioperative complication 34 (4.4) 15 (0.9) <0.001  Infection 12 (35.2) 6 (40.0)  Heart failure 4 (11.7) 0 (0.0)  Transfer to ICU 20 (58.8) 5 (33.3)  Intestinal obstruction 2 (5.8) 2 (0.1)  Thromboembolic events 3 (8.8) 3 (0.2) LOS, day 6 (2–8) 5 (2–7) <0.001 Hospitalization cost, yuan 14531 (5614–23,343) 13,681 (5538–21,514) 0.044 Notes : Mann–Whitney U -test for continuous variables, χ² -test for categorical variables.Medians (IQR) for continuous variables, frequencies (%) for categorical variables. Abbreviations : ICU, intensive care unit; LOS, length of stay; IQR, interquartile range. Table 3 Multivariate Analyses of Perioperative Transfusion and Complication Perioperative Complication Perioperative Transfusion aOR (95% CI) P aOR (95% CI) P BMI 0.893 (0.815–0.979) 0.016 0.924 (0.863–0.989) 0.023 Comorbidity 4.422 (2.078–9.410 <0.001 2.702 (1.586–4.601) <0.001 Preoperative anemia 6.259 (2.937–13.342) <0.001 15.932 (8.258–30.740) <0.001 Gynecological malignancy 4.376 (1.844–10.383) <0.001 – – Surgery duration 1.010 (1.005–1.014) <0.001 1.006 (1.002–1.009) 0.003 Volume of blood loss 1.002 (1.001–1.002) <0.001 1.006 (1.005–1.007) <0.001 Notes : - no statistical analysis. Logistic regression analyses were used. Abbreviations : BMI, body mass index; aOR, adjusted odds ratio; CI, confidence interval. Comparison Between Anemic and Non-Anemic Groups in Total Inpatients Notes : Mann–Whitney U -test for continuous variables, χ² -test for categorical variables.Medians (IQR) for continuous variables, frequencies (%) for categorical variables. Abbreviations : ICU, intensive care unit; LOS, length of stay; IQR, interquartile range. Multivariate Analyses of Perioperative Transfusion and Complication Notes : - no statistical analysis. Logistic regression analyses were used. Abbreviations : BMI, body mass index; aOR, adjusted odds ratio; CI, confidence interval. The total patients were then divided into non-gynecological malignancy group and gynecological malignancy group according to the final surgery pathology. In patients without gynecological malignancy, the incidence of preoperative anemia was 30.4% (690/2266). Similar to the previous results, anemic group displayed younger age (43 vs 46, P < 0.001), lower BMI (23.3 vs 23.8, P < 0.001), higher incidences of perioperative RBC transfusion (7.5% vs 0.5%, P < 0.001) and complication (1.6% vs 0.2%, P < 0.001) and longer LOS (6 vs 5, P = 0.004) ( Table 4 ). The multivariate analyses showed that, preoperative anemia were related with both perioperative complication (aOR = 5.609, P = 0.012) and perioperative RBC transfusion (aOR = 23.406, P < 0.001) ( Table 5 ). Table 4 Comparison Between Anemic and Non-Anemic Groups in Patients with or Without Gynecological Malignancies Non-gynecological Malignancies Gynecological Malignancies Anemic (n = 690) Non-Anemic (n = 1576) P Anemic (n = 86) Non-Anemic (n = 167) P Age, years 43 (37, 50) 46 (37, 57) <0.001 52 (43, 63) 57 (49, 63) 0.052 BMI, kg/m 2 23.3 (21.0, 25.5) 23.8 (21.7, 26.6) <0.001 22.9 (20.9, 25.4) 24.5 (22.4, 26.7) 0.004 Comorbidity 163 (23.6) 466 (29.7) 0.004 36 (41.9) 85 (50.9) 0.173 Surgery duration, minute 50 (20, 98) 44 (18, 92) 0.175 175 (131, 262) 160 (116, 212) 0.064 Volume of blood loss, mL 10 (5, 50) 10 (5, 50) 0.106 225 (100, 400) 100 (50, 400) 0.008 Perioperative transfusion 52 (7.5) 8 (0.5) <0.001 31 (36.0) 21(12.6) <0.001 Perioperative complication 11 (1.6) 3 (0.2) <0.001 23 (26.7) 12 (7.2) <0.001 LOS, day 6 (2, 7) 5 (2, 7) 0.004 11 (8, 18) 11 (7, 14) 0.185 Hospitalization cost, yuan 12524 (5326, 20,947) 11,787 (5323, 19,439) 0.229 45,968 (37,418, 60,905) 42,196 (30,064, 53,693) 0.009 Notes : Mann–Whitney U -test for continuous variables, χ² -test for categorical variables.Medians (IQR) for continuous variables, frequencies (%) for categorical variables. Abbreviations : BMI, body mass index; LOS, length of stay; IQR, interquartile range. Table 5 Multivariate Analyses of Perioperative Transfusion and Complication in Patients with or Without Gynecological Malignancies Non-Gynecological Malignancies Gynecological Malignancies Perioperative Complication Perioperative Transfusion Perioperative Complication Perioperative Transfusion aOR (95% CI) P aOR (95% CI) P aOR (95% CI) P aOR (95% CI) P Age - - 0.941 (0.913–0.969) <0.001 - - - - BMI 0.768 (0.623–0.946) 0.013 0.922 (0.849–1.001) 0.053 - - - - Comorbidity 5.032 (1.482–17.088) 0.010 5.698 (1.866–11.330) <0.001 3.533 (1.406–8.978) 0.007 - - Preoperative anemia 5.609 (1.452–21.664) 0.012 23.406 (9.029–60.675) <0.001 6.021 (2.441–14.853) <0.001 8.813 (3.203–24.248) <0.001 Surgery duration 1.010 (1.001–1.019) 0.028 1.007 (1.002–1.013) 0.013 1.009 (1.004–1.015) <0.001 1.003 (0.997–1.009) 0.268 Volume of blood loss 1.002 (1.001–1.004) 0.004 1.006 (1.004–1.007) <0.001 1.001 (1.000–1.002) 0.032 1.006 (1.004–1.008) <0.001 Notes : - no statistical analysis. Logistic regression analyses were used. Abbreviations : BMI, body mass index; aOR, adjusted odds ratio; CI, confidence interval. Comparison Between Anemic and Non-Anemic Groups in Patients with or Without Gynecological Malignancies Notes : Mann–Whitney U -test for continuous variables, χ² -test for categorical variables.Medians (IQR) for continuous variables, frequencies (%) for categorical variables. Abbreviations : BMI, body mass index; LOS, length of stay; IQR, interquartile range. Multivariate Analyses of Perioperative Transfusion and Complication in Patients with or Without Gynecological Malignancies Notes : - no statistical analysis. Logistic regression analyses were used. Abbreviations : BMI, body mass index; aOR, adjusted odds ratio; CI, confidence interval. In patients with gynecological malignancy, the incidence of preoperative anemia was 34.0% (86/253). Compared with non-anemic group, anemic group had lower BMI (22.9 vs 24.5, P = 0.004), higher incidences of perioperative RBC transfusion (36.0% vs 12.6%, P < 0.001) and complication (26.7% vs 7.2%, P < 0.001) and higher hospitalization costs (45968 vs 42196, P = 0.009) ( Table 4 ). The multivariate analyses indicated that preoperative anemia were related with both perioperative complication (aOR = 6.021, P < 0.001) and perioperative transfusion (aOR = 8.813, P < 0.001) ( Table 5 ). In this study, 11.5% (89/776) of patients took measures to improve preoperative anemia such as: oral iron supplements (n = 26), intravenous iron supplements (n = 35) and RBC transfusion (n = 28). Among which, 43.8% (39/89) had moderate anemia, and 49.4% (44/89) had severe anemia. We found that patients who received iron supplementation or RBC transfusion preoperatively had higher rates of intra/post-operative blood transfusion and complication, compared with those without preoperative blood management ( Table 6 ). Given that most of these patients had comorbidities, lower Hb concentration before surgery, or had malignant tumors, we conducted multivariate logistic regression analyses to mitigate the influence of confounding factors ( Table 7 ). It indicated that preoperative RBC transfusion was a protective factor against perioperative complication (aOR = 0.032, P = 0.017), while the relationship between iron supplementation and perioperative complication remained unclear (aOR = 0.628, P = 0.502). Also, the Hosmer-Lemeshow goodness-of-fit test displayed the good performance of the logistic regression model (P > 0.05). Table 6 Comparison Between Anemic Patients with or Without Blood Management Iron Supplementation (N = 61) Preoperative RBC Transfusion (N = 28) Without Blood Management (N = 687) P value Age, years 43 (40, 50) 44 (32, 50) 44 (37, 52) 0.491 BMI, kg/m 2 22.7 (21.0, 25.0) 23.3 (20.3, 26.4) 23.3 (21.0, 25.5) 0.951 Comorbidity 19 (31.1) 18 (64.3) 164 (23.9) <0.001 Gynecological malignancy 13 (21.3) 3 (10.7) 70 (10.2) 0.03 Hb concentration before surgery, g/L 89 (78, 96) 68 (62, 74) 109 (103, 115) <0.001 Surgery duration, minute 73 (27, 154) 70 (62, 74) 60 (20, 112) 0.089 Volume of blood loss, mL 30 (5, 200) 30 (5, 300) 10 (5, 50) 0.018 Intra/post-operative RBC transfusion 12 (19.7) 13 (46.4) 41 (6.0) <0.001 Perioperative complication 9 (14.8) 2 (7.1) 23 (3.3) <0.001 Hospitalization cost, yuan 19318 (7013, 32,760) 22,803 (13,069, 32,205) 13,891 (5409, 22,665) <0.001 LOS, day 7 (4, 11) 8 (6, 14) 6 (2, 8) <0.001 Notes : Kruskal–Wallis H -test for continuous variables, χ² -test for categorical variables.Medians (IQR) for continuous variables, frequencies (%) for categorical variables. Abbreviations : BMI, body mass index; Hb, hemoglobin; RBC, red blood cell; LOS, length of stay; IQR, interquartile range. Table 7 Multivariate Analyses of Perioperative Complication and Intra/Post-Operative Transfusion in Anemic Patients Perioperative Complication Intra- or Post-Operative RBC Transfusion aOR 95% CI P aOR 95% CI P Age 1.048 1.011–1.085 0.010 - - - BMI - - - 0.850 0.765–0.944 0.002 Comorbidity - - - 2.405 1.132–5.110 0.022 Hb concentration before surgery 0.912 0.875–0.950 <0.001 0.930 0.908–0.952 <0.001 PBM before surgery  No (reference) - - - - - -  Preoperative RBC transfusion 0.032 0.002–0.539 0.017 - - -  Iron supplementation 0.628 0.162–2.441 0.502 - - - Gynecological malignancy 7.287 2.138–24.836 0.002 - - - Surgery duration 1.008 1.002–1.014 0.015 1.012 1.007–1.017 <0.001 Volume of blood loss 1.002 1.001–1.003 0.001 1.006 1.004–1.007 <0.001 Notes : - no statistical analysis. Logistic regression analyses were used. Abbreviations : BMI, body mass index; Hb, hemoglobin; PBM, patient blood management; RBC, red blood cell; aOR, adjusted odds ratio; CI, confidence interval. Comparison Between Anemic Patients with or Without Blood Management Notes : Kruskal–Wallis H -test for continuous variables, χ² -test for categorical variables.Medians (IQR) for continuous variables, frequencies (%) for categorical variables. Abbreviations : BMI, body mass index; Hb, hemoglobin; RBC, red blood cell; LOS, length of stay; IQR, interquartile range. Multivariate Analyses of Perioperative Complication and Intra/Post-Operative Transfusion in Anemic Patients Notes : - no statistical analysis. Logistic regression analyses were used. Abbreviations : BMI, body mass index; Hb, hemoglobin; PBM, patient blood management; RBC, red blood cell; aOR, adjusted odds ratio; CI, confidence interval.

This was a single-center, retrospective study using data collected from surgical patients admitted to the Department of Gynecology at Peking University People’s Hospital between April 2023 and January 2024. The data included demographic information, preoperative laboratory tests, diagnoses, surgery records, and hospitalization information. Patients under 18 years old or with missing pre-operative hemoglobin lab recordings within 30 days prior to operation or other significant information were excluded. All preoperative diagnoses in this study were based on International Classification of Diseases (ICD) −10 codes and the diagnosis of malignant tumors was based on the final surgical pathology. The sample size required for this study was calculated using Power Analysis and Sample Size (PASS) 2021 software, based on the different perioperative complication rates between the anemic group and the non-anemic group. Previous literature indicated that the prevalence of preoperative anemia among Chinese adult women was 31.5%. 13 Based on preliminary statistics from our center, the perioperative complication rate in anemic patients is approximately 4% (p1), while that in non-anemic patients is about 0.5% (p2). Therefore, we employed the formula for comparing two independent proportions, setting the test power at 90% and the two-sided significance level at 0.05. The sample size for the anemic group was designated as N1, and that for the non-anemic group as N2, with N2/N1 = 2.3. Calculations indicated the minimum sample sizes for the two groups were 348 and 800, respectively. This study used the WHO criteria to screen and estimate the degree of anemia. It defined anemia as a hemoglobin concentration less than 120 g/L in non-pregnant adult females (mild: 110–119 g/L, moderate: 80–109 g/L, severe: <80 g/L). 3 , 4 Demographic data included age, body mass index (BMI) and comorbidities. Diagnoses were based on ICD-10. Surgery records encompassed surgery grade, surgery duration and volume of blood loss; the surgery grade was based on the Management Measures for Surgery Grading in Medical Institutions issued by China’s National Health Commission, which categorized surgeries into Grade 1 to 4 according to factors such as surgery risk, complexity, and consumed resources. A greater number indicated higher surgery risk and increased complexity. Hospitalization information covered LOS and hospitalization costs. The primary outcomes of this study were perioperative complications, including infection, heart failure, thromboembolic event, intestinal obstruction, and transfer to the intensive care unit (ICU). Infection encompassed surgical site infection, respiratory tract infection, gastrointestinal infection, urinary tract infection and sepsis, which were diagnosed based on definitive pathogenetic evidence or consultation with infectious disease specialists. Thromboembolic events encompassed deep vein thrombosis, pulmonary embolism, acute myocardial infarction and stroke, diagnosed based on definitive imaging evidence. Secondary outcomes included perioperative red blood cell (RBC) transfusion, LOS and hospitalization costs. Our center used restrictive transfusion strategy, in which a trigger of Hb concentration <70 g/L was recommended. Outcomes were collected from 7 days before surgery to 30 days after surgery. Descriptive statistical analysis was used. Continuous variables were presented as medians (interquartile range (IQR)), and categorical variables were presented as frequencies (percentages). The distribution of continuous variables was compared using the Mann–Whitney U -test or the Kruskal–Wallis H -test, categorical variables were compared using the χ 2  test. Univariate logistic regression analysis was used to screen for confounding variables. Variables with P value < 0.1 were conducted in multivariate logistic regression analysis to identify risk factors associated with the study outcomes and the Hosmer-Lemeshow goodness-of-fit test was used to evaluate the model. P value < 0.05 was considered significant. The above analyses were conducted with IBM SPSS Statistics for Windows, version 27.0.1.

Preoperative anemia was related to higher incidence of perioperative RBC transfusion and complication, and it increased hospitalization costs and prolonged LOS in gynecological inpatients. PBM before surgery could help improve perioperative outcomes. These findings emphasized the importance of early identification and active management of anemia, which might help reduce transfusion needs, minimize complications, and ultimately enhance gynecological inpatients’ outcomes.

This is a single-center, retrospective study of gynecological inpatients, aiming to investigate the incidence of preoperative anemia and its impact on perioperative outcomes. We found that the incidence of preoperative anemia was 30.8% (776/2519), and patients with preoperative anemia displayed younger age and lower BMI. Multivariate logistic regression analyses showed that preoperative anemia was an independent risk factor for perioperative transfusion and perioperative complication. In addition, preoperative anemia prolonged LOS and increased hospitalization costs. The intervention rate of preoperative anemia in our study was only 11.5% (89/776), and common measures included iron supplementation and RBC transfusion. Multivariate logistic regression analyses indicated that preoperative RBC transfusion was a protective factor against perioperative complication. Our study indicated that the overall prevalence of preoperative anemia among gynecological surgery patients is 30.8%, which was consistent with previous researches. 13 However, unlike previous studies, we found that anemic patients were younger, which might be due to differences in disease patterns. For instance, vaginal bleeding, uterine leiomyoma and adenomyosis predominantly affected women of reproductive age, accounting for 30.4% and 20.2% in the anemic and non-anemic groups, respectively. Conversely, pelvic floor dysfunction was more common in older individuals, accounting for 5.5% and 13.0% in the two groups, respectively. The prevalence of preoperative anemia in patients with malignancy was 34.0%, slightly higher than that in patients without malignancy (30.4%). The research conducted by Kexue Ning et al showed that the prevalence of anemia in patients with gynecological cancer reached as high as 59.06%. 14 The high prevalence of preoperative anemia among malignant tumor patients could be attributed to the following factors: Most malignant tumor patients were in the state of consumption, so that inadequate nutritional intake leaded to deficiencies in hematopoietic precursors (such as iron, vitamin B12, folic acid, etc). Furthermore, malignancy resulted in chronic inflammation that could cause iron-restricted erythropoiesis due to increased levels of hepcidin; the inflammation could also impact the interpretation of ferritin levels. 15 Consistent with previous studies, our study found that preoperative anemia was associated with higher occurrence of perioperative complication and perioperative RBC transfusion in gynecological inpatients. 5 , 8 , 15 , 16 Olivia W Foley et al conducted a study involving 60017 patients undergoing surgery by gynecologic oncologists and found that, pre-operative anemia had increased odds of infectious complications (OR = 1.16, 95% CI 1.07 to 1.26), thromboembolic complications (OR = 1.39, 95% CI 1.15 to 1.68), and blood transfusion (OR = 5.78, 95% CI 5.34 to 6.26). 8 A multicenter study involving 5,572 patients undergoing gynecological procedures from Canada showed that preoperative anemia was associated with increased ICU admissions and hospital length of stay. 15 A retrospective study of 98813 patients who underwent a laparoscopic hysterectomy for benign indications revealed that, preoperative anemia was identified as an independent risk factor for extended length of stay, readmission and composite morbidity after surgery. 16 These findings unanimously highlighted the importance of implementing patient blood management. According to the Expert Consensus on Perioperative Blood Management in Gynecological Patients, therapeutic measures of preoperative anemia include oral/intravenous iron supplements, erythropoietin, and treatment of primary disease. 17 In our study, 11.5% (89/776) of patients took measures to improve anemia, among which, 93.3% had moderate to severe anemia. Compared with those without preoperative PBM, patients who received iron supplementation or RBC transfusion preoperatively displayed higher rates of intra/post-operative blood transfusion and complication. It might be explained by the following reasons: (1) Most of those patients had moderate to severe anemia, and the severity of anemia was also correlated with the rate of perioperative outcomes. 16 It had also been confirmed by the results of the logistic regression model ( Table 7 ), displaying that lower Hb concentration before surgery was a risk factor for perioperative complication and RBC transfusion. (2) Consensus stated that oral iron should start at least 6 to 8 weeks before surgery, so the insufficient duration of oral iron supplement might not achieve the goal of improving anemia. As Table 7 showed, preoperative restrictive RBC transfusion can rapidly improve anemia, which appeared to be a protective factor against perioperative complication. Our findings emphasized the importance of screening and managing anemia before surgery. To integrate preoperative PBM into routine preoperative protocols, we proposed the following approach. 17 , 18 Routine complete blood counts should be performed during the initial consultation for surgical patients. If it indicated anemia, further tests should be conducted to identify underlying causes such as deficiencies in hematopoietic precursors (iron, vitamin B12, folic acid), excessive blood loss, or hematologic disorders. An individualized PBM plan should be developed based on the patient’s general condition, Hb concentration, cause of anemia, type of surgery, and anticipated blood loss during surgery. For Hb 100 g/L, drug therapy was employed; for Hb between 70 and 100 g/L, decision depended on specific circumstances. 17 Currently, commonly used medications included oral iron supplements, intravenous iron supplements, folic acid, and vitamin B12, erythropoietin was not routinely recommended. The most common type of anemia in gynecology was iron deficiency anemia. For elective benign surgeries, oral iron supplements for 6–8 weeks should be selected. For emergency or limited surgeries requiring rapid anemia correction, intravenous iron was more recommended. Additionally, anemic patients should adjust their dietary structure, emphasize food diversity and balanced nutrition, and seek guidance from clinical nutritionists when necessary. Our study had the following limitations: (1) This was a single-center retrospective study, and there might be bias in case selection. (2) Limited to the sample size, the number of perioperative complications is small in some subgroups, which may result in unstable estimates and wide confidence intervals. And the potential for overfitting might exist in logistic regression model. Therefore, we introduced the Hosmer-Lemeshow goodness-of-fit test to evaluate the model. (3) This study was a retrospective study without long-term follow-up, failing to evaluate long-term complications and prognosis.