Borderline ovarian tumors are neoplasms with low malignant potential, representing a group of lesions that possess characteristics of both benign and malignant tumors. They account for 15–20% of all epithelial ovarian tumors and primarily affect young women, in contrast to ovarian carcinoma. The most common histotypes include serous variants (53%). Serous borderline ovarian tumor (SBOT) is a condition that can manifest and even progress during pregnancy, leading to significant clinical and diagnostic challenges.

Object of Study: Women with borderline ovarian tumors or their recurrences during pregnancy. The course of borderline tumors during pregnancy.

Objective of the Study: To assess the impact of this condition on the course of pregnancy, delivery, and the newborn, and to determine the favorable timing for surgical treatment of these tumors.

Materials of the Study: This report will present a retrospective and prospective analysis of patients with borderline ovarian tumors during pregnancy. A total of 17 patients of reproductive age (according to WHO criteria, reproductive age for women ranges from 15 to 49 years) with histologically confirmed diagnoses of serous borderline ovarian tumors were included in the study. Conservative and ultra-conservative surgical treatments during pregnancy and after delivery were considered. To evaluate the dynamics, specific tumor markers (CA-125, HE4, ROMA index) were determined, and pelvic ultrasound and pelvic MRI were used. Statistical processing of the data obtained was performed.

Results: All patients conceived in natural cycles. One patient underwent radical treatment after delivery due to combined uterine pathology, six patients received conservative treatment during pregnancy, and ten patients underwent ultra-conservative treatment, of which four were operated on in the early postpartum period. Five patients were delivered via cesarean section due to associated pathology, while the other 12 had spontaneous deliveries. All newborns were assessed using the Apgar scale, scoring 8/9. A widespread process in the contralateral ovary was identified in one patient, while no cases of spread to the greater omentum or parietal peritoneum were found. In 16 patients, SBOT was limited to one ovary.

Prolonging pregnancy in the presence of borderline ovarian tumors is acceptable, as this condition does not adversely affect pregnancy outcomes. Surgical intervention can be performed both during gestation and after delivery. Considering the reproductive age of the patients, it is important to explore conservative and ultra-conservative approaches to surgical treatment. The occurrence of SBOT recurrences following non-radical treatment during pregnancy is extremely rare, thus planning for pregnancy after primary treatment can be recommended immediately following surgery. Laboratory diagnostics involving blood tumor marker levels during pregnancy in patients with SBOT do not significantly differ from the levels in healthy women and generally exhibit normal values. Instrumental diagnostics with high validity can assist surgeons in making the right decisions to optimize surgical treatment.

Conclusion: Despite the potential risks associated with borderline ovarian tumors and surgical intervention during pregnancy, timely diagnosis and appropriate management strategies can significantly improve the prognosis for both the mother and the fetus. A multidisciplinary approach is necessary for this pathology, encompassing obstetricians, gynecologists, and oncologists to optimize surgical treatment while preserving the reproductive function of the patients.