The clinical characteristics and prognosis of surgically treated ovarian endometrioma in pregnant women

Ovarian endometrioma presents various changes during pregnancy and caution should also be taken for recurrence after delivery. Surgical intervention is prompted mainly by suspected malignancies which is difficult to distinguish with decidualization.

The study included 21 patients who underwent surgery during the first and second trimester, resulting in 24 histologically confirmed lesions (Table  1 and Table  2 ). All patients had natural pregnancies, with an average age of 31.14 (range: 23–46) years. Among them, 10 had a history of dysmenorrhea, with a median Visual Analog Scale (VAS) score of 6. Before pregnancy, 12 patients had ovarian cysts, but only 1 case was confirmed through surgical pathology. The initial maximum diameter was 7.47 cm and 8.97 cm preoperatively with 19 patients larger than 6 cm, with 6 exceeding 10 cm. The average gestational age at the time of surgery was 16.67 (range: 12 +2 –25 +6 ) weeks and the pathology reports showed 1 endometrioid carcinoma (Table  3 , case 1), and the remaining 23 lesions indicated OMA, including 7 cases with significant decidualization. Table 1 General clinical and follow-up characteristics of the patients Surgery during pregnancy ( n  = 21) Surgery during cesarean ( n  = 9) Age 31.14 ± 5.19 37.67 ± 4.47 BMI 23.03 ± 3.01 23.54 ± 3.70 Menarche age 13 [ 13 , 14 ] 13.00 ± 0.87 Dysmenorrhea history 10 (47.62%) 5 (55.56%) VAS before pregnancy 6 [4.75, 6.25] 6 [4.5, 6] Primiparous 16 (76.19%) 0 History of ovarian surgery 1 (4.76%) 2 (22.22%) IVF-ET 0 2 (22.22%) Discovery before pregnancy 12 (57.14%) 7 (77.78%) History before pregnancy 1.66 ± 1.34 2.50 ± 1.38 Side of cyst  Left 12 (57.14%) 3 (33.33%)  Right 6 (28.57%) 5 (55.56%)  Bilateral 3 (14.29%) 1 (11.11%)  Initial size 7.47 ± 3.57 3.89 ± 1.26  Last size 8.97 ± 2.79 4.11 ± 1.56  Maximum diameter ≥ 6 cm 19 (90.48%) 0  Maximum diameter ≥ 10 cm 6 (28.57%) 0  Gestational age at surgery 16.67 ± 3.44 38 [37.5, 38.5] Pathology  Endometrioma 13 (61.90%) 6 (66.67%)  Decidualized endometrioma 7 (33.33%) 3 (33.33%)  Malignant tumor 1 (4.76%) 0 Results of Follow-up (n = 19)  Duration of follow-up 5.38 ± 3.48 4.73 ± 2.70  Postoperative recurrence 1 (5.26%) 1 (11.11%)  Postoperative adenomyosis 2 (10.53%) 0  Current Dysmenorrhea 5 (26.32%) 4 (44.44%)  Current VAS 3 [3, 4.5] 2.4 ± 0.68 BMI Body mass index, VAS Visual analog score, IVF-ET: In vitro fertilization and embryo transfer.Initial size: cyst indicated by the first ultrasound during pregnancy, Last size: cyst indicated by the last ultrasound indicating the presence of cyst Table 2 Ultrasound characteristics, Surgical and pregnancy outcomes of the patients who had surgery during mid-pregnancy Ultrasound characteristics (n = 24) Surgical and pregnancy outcomes ( n  = 21) Changes during Pregnancy Indications of operation No obvious change 13 (54.17%) Papillary projection 10 (47.62%) Increase 10 (41.67%) High tumor markers and large cysts 3 (14.29%) Decrease 1 (4.17%) Only high tumor markers 3 (14.29%) Irregular shape 3 (12.50%) Only large cyst 3 (14.29%) Thick-walled cyst 6 (25.00%) Ovarian cyst torsion 2 (9.52%) Multi locular cyst 11 (45.83%) Intraoperative findings Echogenicity of cyst fluid Obvious adhesion 5 (23.81%) Ground glass 9 (37.5%) Closed/semi-closed rectouterine pouch 6 (28.57%) Solid 8 (33.33%) Surgical type Anechogenic 7 (29.17%) Oophorocystectomy 18 (85.71%) Papillary projection 10 (41.67%) Adnexectomy 3 (14.29%) Multiple papillae 4 (40.00%) Surgery time (min) 40 [40–47.5] Doppler examination Blood loss (ml) 20 [20–50] No blood flow 3 (30.00%) Recovery days in the hospital 3 [ 3 – 3 ] Minimal blood flow 4 (40.00%) Gestational age at delivery 39.14 ± 1.11 Moderate blood flow 2 (20.00%) Cesarean delivery 11 (52.38%) Very strong blood flow 1 (10.00%) Preterm labor 2 (9.52%) Table 3 Basic clinical features of 5 special cases Case Age BMI G/P VAS Changes in cysts Markers Ultrasonic characteristics 1 27 22.58 1/0 No Left: 2.5 cm (7 months before pregnancy)-5.4 cm (Early pregnancy)-7.9 cm (preoperatively) Right: no cysts before pregnancy, and about 2.8 cm during pregnancy AFP:31.1 Left: Regular morphology, thin walls, and multilocular cysts with fluid appear anechoic. Solitary papilla 3.2 cm with a small amount of blood flow signal present (Left) and no papillary (Right) 2 28 23.44 2/0 7 Right: 4.8 cm (1 year before pregnancy)-4.8 cm (Early pregnancy)-8.4 cm (preoperatively) Negative Regular morphology, thick walls, and unilocular cysts with fluid appear as solid or mass-like echoes. Solitary papilla 1.5 cm with no blood flow signal present 3 23 21.45 1/0 6 Left: first detected in early pregnancy (11.4 cm) and about 11 cm during pregnancy CA-125: 385 CA199:163 AFP: 33.5 Regular morphology, thin walls, and unilocular cysts with fluid appear as fine, dense, dot-like echoes. No papillary projections are present 4 30 20.76 2/0 7 Right: first detected in the early pregnancy (7.9 cm) -10 cm (preoperatively) Negative Regular morphology, thick walls, and multilocular cysts with fluid appear as fine, dense, dot-like echoes. No papillary projections are present 5 33 23.44 1/0 6 4 years before pregnancy: 2 cm (right) and 4 cm (left) Early pregnancy: 3.2 cm and 4.7 cm respectively During pregnancy: no significant growth and not reported in the late stages of pregnancy Negative Regular morphology, thin walls, and unilocular cyst with fluid appear anechoic. No papillary projections are present Case 1 was the only malignant patient; cases 2–3 developed adenomyosis and cases 4–5 developed recurrence during follow-up. BMI Body mass index (kg/m 2 ), G/P Gravida/ Para, VAS: visual analog scale, AFP Alpha-fetoprotein (ng/ml), CA-125 Carbohydrate antigen 125(U/ml), CA199 Carbohydrate antigen 199(U/ml) General clinical and follow-up characteristics of the patients BMI Body mass index, VAS Visual analog score, IVF-ET: In vitro fertilization and embryo transfer.Initial size: cyst indicated by the first ultrasound during pregnancy, Last size: cyst indicated by the last ultrasound indicating the presence of cyst Ultrasound characteristics, Surgical and pregnancy outcomes of the patients who had surgery during mid-pregnancy Basic clinical features of 5 special cases Left: 2.5 cm (7 months before pregnancy)-5.4 cm (Early pregnancy)-7.9 cm (preoperatively) Right: no cysts before pregnancy, and about 2.8 cm during pregnancy CA-125: 385 CA199:163 AFP: 33.5 4 years before pregnancy: 2 cm (right) and 4 cm (left) Early pregnancy: 3.2 cm and 4.7 cm respectively During pregnancy: no significant growth and not reported in the late stages of pregnancy Case 1 was the only malignant patient; cases 2–3 developed adenomyosis and cases 4–5 developed recurrence during follow-up. BMI Body mass index (kg/m 2 ), G/P Gravida/ Para, VAS: visual analog scale, AFP Alpha-fetoprotein (ng/ml), CA-125 Carbohydrate antigen 125(U/ml), CA199 Carbohydrate antigen 199(U/ml) Among the 24 lesions, 13 showed no change in cyst size, 10 had enlargement, and 1 displayed shrinkage. 11 lesions had multi cystic septate d cysts, 6 had thickened cyst walls, and 3 had irregular cyst morphology. Regarding cyst fluid echogenicity, 9 lesions had uniform dense punctate echoes, creating a distinct “ground glass” appearance, 8 had solid areas with patchy or mass-like hyperechoic echoes, and 7 had no apparent echoes. Additionally, 10 lesions had papillary projections, with 4 having multiple projections. Among these, 3 showed no detectable blood flow signal, 4 had minimal blood flow, 3 had moderate blood flow intensity, and 1 exhibited strong blood flow signals (Table  2 ). Surgical indications varied among the patients (Table  2 ). Sixteen cases were suspected to be malignant, among them, 9 showed papillary growth inside the cyst, 6 had considerably elevated tumor markers, with 3 also having cysts larger than 10 cm in diameter, and 1 patient had both papillary growth and elevated tumor markers. There were 3 cases with persistent cysts exceeding 10 cm, and the remaining 2 cases had ovarian cyst torsion. All surgeries were performed laparoscopically, with 3 patients undergoing unilateral adnexectomy due to the absence of future fertility desires or malignancy and the remaining 18 patients underwent cystectomy. Five cases involved significant cyst adhesions, and 6 cases required closure or partial closure of the rectovaginal pouch based on intraoperative findings. The median surgical time was 40 min, with a median intraoperative bleeding of 20 ml. Postoperatively, all patients received intramuscular progesterone, and the median length of hospital stay was 3 days (Table  2 ). During the follow-up period, two patients were lost and all of the remaining 19 patients successfully delivered their babies. Two cases were delivered at 36 +4  weeks and 36 +6  weeks, respectively, while the rest 17 had full-term deliveries. Eight patients gave birth vaginally, while 11 underwent cesarean section. One patient experienced recurrence after surgery and 2 developed adenomyosis (Table  3 , cases 2–4) in the long-term follow-up. Among the 10 cases of patients with dysmenorrhea, 3 cases experienced a mild reduction in symptoms compared to before (VAS score < 3), 2 cases showed significant alleviation, and the remaining 5 cases showed complete resolution of symptoms (Table  3 ). The only malignant patient (Table  3 , case 1) was closely monitored throughout the postoperative pregnancy with no abnormalities indicated both in ultrasound and tumor markers. Due to suspected fetal distress, the pregnancy was terminated via cesarean section at 39 +5  weeks. No metastatic lesions and enlarged lymph nodes were found during the cesarean section. The left adnexa was absent, and no apparent abnormalities were detected in the uterus and right adnexa. Partial tissue samples were obtained from the recto uterine pouch adhesions, bilateral uterosacral ligament peritoneum, left infundibulopelvic ligament peritoneum, bilateral pelvic wall peritoneum, greater omentum, bilateral colonic gutter peritoneum, right ovary for pathological examination and no evidence of residual cancerous lesions based on the pathology results Table  4 . Table 4 The operation and postoperative follow-up of 5 special cases Case GA at surgery Intraoperative findings Surgical type Pathology Follow time GA at delivery Delivery mode Follow-up and Management 1 17 +4 Slight adhesion in the left adnexa, semi-closed rectouterine pouch. Cyst fluid is thin and brown, and the papillary projection shows cauliflower-like structures Left adnexectomy, right cystectomy Left: endometrioid carcinoma Right: endometrioma with stromal hyalinization 0.5 39 +5 Cesarean No elevation in tumor markers and ultrasound indicate no recurrence. Multiple biopsies were performed during cesarean section, and the pathological results did not reveal any malignant lesions 2 20 +5 No adhesion and unable to expose rectouterine pouch. The papillary projections appear smooth Right cystectomy Endometrioma 10.5 38 Cesarean Adenomyosis developed and an LNG-IUD was placed after GnRHa. Dysmenorrhea decreased (VAS = 5) 3 16 +4 Slight adhesion and unable to expose rectouterine pouch Left cystectomy Endometrioma 8.6 40 Vaginal Adenomyosis developed and an LNG-IUD was placed after GnRHa. Dysmenorrhea decreased (VAS = 4) 4 12 +2 Obvious adhesion, semi-closed rectouterine pouch Right cystectomy Endometrioma 5.75 36 +4 Vaginal One year postoperatively, there was a recurrence of a cyst on the right side with a diameter of 2-3 cm and not treated. Dysmenorrhea decreased (VAS = 3) 5 38 +1 Slight adhesion and unable to expose rectouterine pouch Left cyst excision, right side not explored Endometrioma 3.6 38 +1 Cesarean Two years postoperatively, there was a recurrence on both sides with a diameter of 4 cm. Sequential dienogest after GnRHa. Dysmenorrhea decreased (VAS = 4) GA Gestational age, VAS Visual analog scale, LNG-IUD Levonorgestrel intrauterine device, GnRHa Gonadotropin-releasing hormone agonist The operation and postoperative follow-up of 5 special cases Left: endometrioid carcinoma Right: endometrioma with stromal hyalinization GA Gestational age, VAS Visual analog scale, LNG-IUD Levonorgestrel intrauterine device, GnRHa Gonadotropin-releasing hormone agonist A total of 9 patients underwent cystectomy during cesarean section, with a total of 10 lesions. One case was delivered at 34 +5  weeks due to premature rupture of membranes, while the remaining cases were delivered at full term. The average age of the patients was 37.67 years, with an average BMI of 23.54 kg/m 2 . Among the patients, seven cases had preoperative diagnoses of ovarian cysts, and two cases had previous surgical pathology diagnoses, with one case showing endometriosis concurrent features of borderline mucinous tumor. The ultrasound findings of all the lesions demonstrated regular and smooth-walled unilocular cysts, with diameters smaller than 6 cm. The cyst fluid showed no echoes or fine ground-glass appearance, and no papillary projections were observed. Pathological examination confirmed endometriosis in all ten lesions, with three lesions showing significant decidualization. Among the five cases with a history of dysmenorrhea, the average VAS score was 5.4. The average follow-up duration after surgery was 4.73 years, with four cases showing significant improvement and one case experiencing postoperative recurrence (Table  3 , case 5).

Cases of patients diagnosed with gestational combined OMA, confirmed through surgical procedures, were retrospectively collected at our singular center between December 2012 and December 2023. Cases that lacked surgical confirmation and were solely suspected based on ultrasound or medical history were excluded from the scope of this study. The study protocol was approved by the Peking Union Medical College Hospital Ethics Committee (K4584, 08/30/2023). General clinical characteristics, ultrasound findings, and surgical management information were collected from medical records. Postoperative follow-up data were obtained from outpatient clinic records and telephone interviews. General clinical characteristics included age, body mass index (BMI), menarche age, dysmenorrhea history, previous pregnancy, and delivery history, history of previous ovarian surgeries, the timing of OMA discovery (before or during pregnancy), presence of elevated tumor markers (CA-125 level above 60 U/ml or elevated CA199) [ 15 ], gestational age at the time of surgery, and postoperative pathological findings. Ultrasonography findings included cyst size and location, changes observed during pregnancy, and imaging characteristics such as whether the cyst had an irregular shape, thick walls, or a multilocular appearance, the echogenicity of cyst fluid, the presence of papillary projections within the cyst wall, and the Doppler examination. Surgical management information encompassed indications for surgery, intraoperative findings, surgical types, surgical time and bleeding, and postoperative recovery time. Follow-up information included the duration of follow-up, gestational age at delivery, delivery mode, postoperative recurrence, and relief of dysmenorrhea. Statistical analysis was conducted using SPSS 22.0 software. Continuous variables that follow a normal distribution are reported as mean ± standard deviation, while non-normally distributed variables are presented as median [interquartile range]. Binary categorical variables are expressed as n (%).

In this study, we have summarized the clinical and prognostic outcomes of 30 patients diagnosed with pregnancy combined with OMA. Among these patients, 21 underwent surgery during pregnancy, while the remaining 9 underwent cystectomy during cesarean section. The main indication for surgery during pregnancy was suspected malignancy; however, the proportion of malignancy was found to be low, and distinguishing between malignant transformation and endometrioma decidualization posed challenges. The changes in cysts during pregnancy can vary, and most patients who underwent surgery during pregnancy had larger cyst volumes without significant reduction during pregnancy in this study. Mid-term laparoscopic surgery during pregnancy was relatively safe as there were no cases of miscarriage among the successfully followed up 19 patients. However, it is important to note that there is still a certain recurrence rate for these patients after delivery, and therefore, vigilant follow-up and management should be exercised. During pregnancy, OMA typically does not present with typical clinical symptoms, except in cases of rupture or acute abdominal pain due to cyst torsion. The behavior of OMA cysts varies during pregnancy, with some lesions resolving while others continue to grow [ 16 ]. Some experts propose that elevated levels of estrogen and progesterone during pregnancy can shrink or even eliminate ectopic ovarian lesions. These cysts often adhere and have limited mobility, reducing the risk of rupture or torsion. However, other researchers suggest that the increased progesterone levels during pregnancy lead to a highly decidualized state of endometriotic lesions, potentially causing enlargement of the cysts and increasing the risk of rupture [ 17 , 18 ]. In this study, out of the 34 ovarian endometrioma lesions in 30 patients, the majority of the cysts either showed no significant changes or exhibited an increase in size. This finding differs from the study by Marie Bailleux et al., as mentioned earlier [ 6 ]. One possible reason for this discrepancy could be related to the patient selection. In our study, all patients underwent surgical treatment, whereas Marie Bailleux et al. included patients based on sonographic indications. Patients with no significant decrease or increase in the size of the cysts are more likely to be considered for surgical treatment. The decidualization of an ovarian endometrioma during pregnancy can sometimes resemble malignant ovarian tumors, posing a diagnostic challenge. Doppler ultrasound imaging may show features in decidualized endometriomas that are similar to malignant cyst walls, including papillary excrescences and abundant blood flow. However, in clinical practice, it can be difficult to differentiate between decidualized endometrioma and ovarian malignancy [ 6 ]. Hence, guidelines recommend referring these patients to specialized centers for further evaluation [ 19 , 20 ]. In this study, among the 7 patients with pathological evidence of decidualization, 5 had cyst walls with papillary projections, and 3 of them showed blood flow signals. This proportion is consistent with previous research [ 5 ]. Some studies suggest that the cyst walls in decidualized endometriomas appear smoother, and additional imaging techniques such as magnetic resonance imaging (MRI) may aid in distinguishing between them [ 5 , 21 ]. MRI, featuring a larger field of view, improves reproducibility, and excellent soft tissue contrast, is being used increasingly frequently in pregnancy nowadays. The guidelines of the American College of Radiology support the safety of the application of MRI during pregnancy, even with 3 Tesla systems. Especially when cancer is diagnosed or highly suspected, MRI is of value in assessing the disease extent during pregnancy [ 22 – 24 ]. However, in our current retrospective cases, corresponding MRI data were lacking. Additionally, changes in tumor markers during pregnancy can also complicate the diagnosis. Alpha-fetoprotein (AFP) may not be significantly diagnostically useful during pregnancy, but an elevated CA-125 level above 60 or an elevated CA199 level can provide some diagnostic reference value [ 15 ]. In the present study, out of the 21 patients who underwent surgery during the first and second trimesters, the majority (16 out of 21) opted for surgery due to suspected malignancy. Among these cases, 9 showed papillary growth inside the cyst, while 6 cases had considerably elevated tumor markers and 1 patient had both papillary growth and elevated tumor markers. Only one patient was diagnosed with malignancy in the final pathological results. This patient's ultrasound showed cyst walls with papillary structures rich in blood flow, and the elevation of tumor markers was only mild for AFP. Choosing the appropriate treatment for adnexal masses during pregnancy requires careful consideration of various factors. Conservative management is often preferred to minimize surgical risks and potential harm to the fetus. In many cases, ovarian tumors with a diameter less than 5 cm in early pregnancy tend to resolve on their own and do not require treatment if asymptomatic [ 8 ]. Complications directly related to pre-existing endometriosis lesions are rare but sometimes can be life-threatening [ 19 , 25 ]. Furthermore, as cysts grow during later stages of pregnancy, the likelihood of needing a cesarean delivery increases [ 19 ] Surgical management is typically necessary for highly suspicious malignancies, large cysts (> 10 cm) that continue to grow, or emergencies such as cyst torsion or rupture [ 9 ]. Surgical management of OMA during mid-term pregnancy is generally considered safe, however, some reports suggest that surgery carries risks of preterm labor and premature rupture of membranes, particularly for large or deeply infiltrating endometriomas [ 18 ]. One must take care to evaluate the patient properly before surgery, especially during pregnancy. The choice of surgical times is also crucial, considering the risks at different stages of pregnancy. The mid-pregnancy period is often considered suitable for surgery, as it occurs after 12 weeks when the placenta has formed and gradually becomes the main source of hormones, reducing dependency on the ovaries. However, the risk of adverse outcomes increases after 24 weeks due to further uterine enlargement [ 12 ]. In this study, apart from 1 case where surgery was performed at 25 +6  weeks, all other pregnant patients underwent surgery between 12 and 24 weeks. The management of endometriosis during pregnancy requires careful consideration of various factors. Surgical treatment, such as ovarian cystectomy, is recommended over drainage/electrocoagulation to reduce the risk of recurrence. Postoperative hormonal treatment for 18 to 24 months is also suggested to prevent a recurrence, especially for patients not seeking immediate conception [ 19 ]. Long-term hormonal therapy may be necessary for some patients. However, there is currently no consensus on managing endometrioma during pregnancy. Recurrence of endometrioma post-surgery is not rare and long-term surveillance is necessary. Breastfeeding is encouraged as it can inhibit ovarian function and potentially reduce the recurrence of endometriosis. However, there is limited research on whether long-term medication management is needed after breastfeeding. In our study, out of 30 patients, two experienced recurrences, while two others developed adenomyosis. It appears that younger age, larger cyst volume, and higher intraoperative disease stage are indicators of high-risk patients (Table  3 ). This retrospective study on the surgical treatment of OMA in pregnant women has several notable strengths. First, there is a relative scarcity of literature on this topic. Despite our study involving only 30 cases, it represents a relatively large volume of research in this relevant field, providing valuable insights for managing this specific population. Second, we have conducted a comprehensive review and summary of the data on these patients, including their medical history, ultrasound imaging characteristics, and intraoperative features. Besides, we have also followed up with them through telephone interviews, including assessing their postoperative pregnancy outcomes and long-term recurrence status. Despite its strengths, this retrospective study has several limitations that should be acknowledged. First, the reliance on medical records introduces the possibility of incomplete or inaccurate documentation, potentially leading to information bias. Additionally, the retrospective nature of the study design limits control over confounding variables and the ability to establish causal relationships between management strategies and outcomes. Moreover, our study suffers from selection bias as we only included patients who underwent surgery, while characteristics of non-surgical patients with concomitant OMA and their pregnancy outcomes were not explored. Overall, despite these limitations, this retrospective study provides valuable insights into the management of OMA during pregnancy. However, further prospective studies with rigorous methodologies are warranted to confirm and expand upon the findings observed in this study. Expanding the sample size and including a control group or non-surgical patients with OMA in future research would bolster the study's reliability and broader applicability. In conclusion, ovarian endometrioma presents diverse changes during pregnancy and caution should also be taken for recurrence after delivery. Surgical intervention is prompted mainly by suspected malignancy and laparoscopic surgery is relatively safe during mid-pregnancy. This study’s findings and discussions provide valuable guidance to clinicians and contribute to the advancement of the surgical management of OMA during pregnancy.

Endometriosis refers to the occurrence, growth, and infiltration of endometrial tissue outside the uterine cavity, leading to periodic bleeding and causing symptoms, such as pain, infertility, nodules, or masses. Approximately 10% of reproductive-aged women are affected by endometriosis, with 30–50% of them reporting infertility [ 1 ]. The clinical pathological classification of endometriosis includes peritoneal endometriosis, ovarian endometrioma (OMA), deep infiltrating endometriosis, and endometriosis in other sites [ 2 ]. OMA, also referred to as "chocolate cysts", is one of the most prevalent types of endometriosis [ 3 ]. In non-pregnant women, ultrasound imaging typically reveals OMA as a well-defined cystic mass with thick walls, regular margins, and uniform and dense punctate echoes within the cyst creating a distinct "ground glass " appearance and the absence of papillary growths [ 4 ]. Endometriosis is a hormone-dependent disease and has unique physiological and pathological characteristics during pregnancy due to specific hormonal changes. Decidualization is a physiological process in which the normal endometrium transforms into a specialized uterine lining suitable for supporting gestation. In ultrasound images, the “decidualization” within the ovary can be easily confused with ovarian borderline/malignant tumors as both share similarities such as papillary projections on the cyst wall and poor acoustic transmission of the cyst fluid due to highly vascularized solid components [ 5 , 6 ]. The incidence of ovarian tumors during pregnancy ranges from 0.05% to 2.4%, with 5–9% being OMA [ 6 , 7 ]. Most ovarian tumors in early-stage pregnancy will spontaneously regress and may not require treatment if they are asymptomatic [ 8 , 9 ]. Surgical intervention for ovarian tumors during pregnancy is usually considered in the following situations: highly suspected malignancy, presence of acute abdomen (such as cyst torsion or rupture), tumor diameter > 10 cm and persistent, severe complications (such as hydronephrosis), and the likelihood of tumor causing obstructed labor [ 9 ]. Laparoscopic surgery has demonstrated good safety with similar or lower rates of adverse fetal outcomes and maternal complications compared to laparotomy [ 9 – 11 ]. Ovarian teratoma and endometrioma have been reported as the two most prevalent types of ovarian cysts that necessitate surgical intervention during pregnancy, accounting for approximately 32% and 15% respectively [ 9 ]. Numerous studies have indicated that OMA, in addition to reducing fertility, may be associated with various adverse pregnancy outcomes, such as spontaneous miscarriage, preterm birth, placenta previa, and postpartum hemorrhage [ 12 – 14 ]. However, there is limited research on the evolution, management strategies, postoperative pregnancy outcomes, and long-term follow-up for patients with OMA operated during pregnancy. Marie Bailleux et al. [ 6 ] reported 53 cases of pregnant patients with confirmed OMA through first-trimester ultrasound. Out of these cases, 33 were monitored through second-trimester ultrasound. The results showed that 8 cases exhibited an increase in size, 11 cases displayed a decrease in size, 5 cases disappeared, and 9 cases remained unchanged. Among the ten cases that underwent postoperative pathology evaluation, only 4 cases were histopathologic ally confirmed as endometriomas, with 1 showing decidualization. Another study conducted by Groszmann et al. [ 5 ] outlined the preoperative sonographic features of 17 consecutive patients with 22 lesions, which were histologically diagnosed as decidualized endometriomas. Among these lesions, 14 had solid components, among which 12 exhibited significant blood flow. Nine patients had follow-up scans and 8 of these masses showed no notable change in size or appearance, and 1 became smaller. In this study, we retrospectively analyze the clinical data of patients who underwent surgical management for OMA during pregnancy or delivery at our center. This analysis aims to provide valuable insights and guidance based on our experience in the management of this specific patient population.