Ovarian masses in pregnant women: clinical and morphological characteristics and the importance of ultrasound monitoring

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Rationale
Over recent decades, thanks to the development and refinement of instrumental diagnostic methods, the detection rate of ovarian masses, including those during gestation, has increased significantly and ranges from 2 to 20 cases per 1000 pregnant patients [1, 2]. According to morphological studies, approximately one-third of ovarian masses are functional cysts—follicular and corpus luteum cysts—which spontaneously regress during pregnancy [3]. Germ cell tumors (mature teratomas) are detected in 24-40% of cases, and epithelial tumors (serous and mucinous cystadenomas) in ~15% [4]. In the vast majority of patients (~70%), ovarian masses are asymptomatic and regress spontaneously. However, lesions characterized by a complex morphological structure, the presence of septa, heterogeneous contents, or a size ≥ 5 cm in diameter typically persist throughout pregnancy and increase the risk of associated complications—primarily torsion and malnutrition, as well as capsule rupture or hemorrhage into the mass due to uterine growth and increased blood supply to the pelvic organs [5, 6].
When deciding on the management strategy for pregnant patients with ovarian masses, the risks and benefits of surgical treatment during gestation must be carefully weighed. However, it should be noted that elective surgery is associated with a lower risk of various complications [7]. Regarding surgical access, most authors emphasize the advantages of laparoscopic access over laparotomy. Thus, Barinov S.V. et al. (2020) using a laparoscopic approach noted less blood loss, shorter operative and hospital stay times, and less severe postoperative pain. When a malignant origin of a space-occupying lesion is suspected, or when a simultaneous cesarean section is required, a lower midline laparotomy is often used as an approach [8].

Objective of the study
—to determine the clinical and morphological features of ovarian space-occupying lesions in pregnant women and to evaluate the diagnostic value of ultrasound examination at various gestational stages.
METHODS
A single-center, retrospective cohort study was conducted, including 45 patients with singleton pregnancies and ovarian space-occupying lesions, who were observed at the Perinatal Center of the S.S. Yudin City Clinical Hospital of the Moscow Department of Health from 2021 to 2024. Using electronic medical records, we examined age, parity of pregnancy and delivery, timing of detection and ultrasound characteristics of ovarian masses, timing and method of delivery, perinatal outcomes, and histological examination results of removed specimens.
Statistical analysis was performed using SPSS 22.0. Quantitative data are presented as mean and standard deviation (M±SD). Qualitative parameters are presented as absolute numbers and relative proportions (%).

RESULTS
The average age of the patients was 30.6±4.3 years. Of these, 25/45 (55.6%) were primiparous and 20/45 (44.4%) were multiparous. Of these, 9/45 (20.0%) had one previous pregnancy, 9/45 (20.0%) had two, and 2/45 (4.4%) had three or more.
7/45 (15.6%) patients had a history of induced abortions, of which 5/45 (11.1%) had one and 2/45 (4.4%) had four. All patients were diagnosed with ovarian space-occupying lesions based on ultrasound data: in 12/45 (26.7%) patients – at various stages of pregnancy, in 5/45 (11.1%) – during ultrasound examination on the eve of delivery, in 2/45 (4.44%) – intraoperatively during cesarean section, and in 26/45 (57.8%) – during ultrasound examination of the pelvic organs after delivery on the eve of hospital discharge. The lesions were most often solitary and located on one side: in 22/45 (48.9%) cases – on the left, and in 22 (48.9%) – on the right. Only in 1/45 (2.2%) patients, space-occupying lesions were present in both ovaries. The average size of detected ovarian masses was 56.6 (±28.7) x 49.0 (±24.9) mm, ranging from 8 x 7 mm to 150 x 125 mm.
Patient management strategies depended on the presence of clinical symptoms and the timing of mass detection. Follow-up was used in 26/45 (57.8%) patients with detected ovarian masses after delivery. Complications were observed in 3/45 (6.7%) women during the second trimester of pregnancy: 2/45 (4.4%) had torsion of the ovarian pedicle, and 1/45 (2.2%) had hemorrhage into the cyst, resulting in emergency laparotomy of the mass. In 16/45 (35.5%) patients, removal of an ovarian mass was performed during cesarean section at full-term pregnancy (≥ 37 weeks), both planned (12/45, 26.7%) and emergency (4/45, 8.9%) for obstetric indications (premature placental abruption - 3/45 (6.7%), severe preeclampsia - 1/45 (2.2%)). Of the 19/45 (42.2%) surgical interventions for removal of ovarian masses, cystectomy was performed in 10/45 (22.2%) cases, adnexectomy in 5/45 (11.1%) cases, and resection of the ovary within healthy tissue in 4/45 (8.9%) cases. Histological examination revealed mature teratomas in 8/45 (17.8%) patients, serous cystadenomas in 4/45 (8.9%), endometrioid cysts in 4/45 (8.9%), and paraovarian cysts in 3/45 (6.7%).
None of the patients who underwent removal of ovarian masses during pregnancy had a preterm birth. All pregnancies resulted in live birth. Vaginal delivery occurred in 25/45 (55.6%) women, while cesarean section was used in 20/45 (44.4%) patients: 11/45 (24.4%) were planned and 9/45 (20%) were emergency cesarean sections for obstetric indications. In 26/45 (57.8%) patients who underwent dynamic observation, spontaneous regression of ovarian masses was observed, which indicates their functional genesis.

DISCUSSION
Ovarian masses, according to the data from this study, were predominantly characteristic of primiparous patients of young reproductive age, which is confirmed by literature data [9].
Of the 45 (100%) patients, ovarian masses were diagnosed during pregnancy at various stages in only 12/45 (26.7%), while in the remaining 33/45 (73.3%), they were detected before, during, or after delivery. The main reason for the late detection of ovarian masses in pregnant women is that during pregnancy, the ultrasound specialist traditionally focuses on a detailed study of the anatomy and an assessment of the functional state of the fetus, while examination of the uterine appendages is not given due attention. Furthermore, the ultrasound examination technique itself has objective limitations. As the fetus grows and the uterus increases in size, the ovaries shift superiorly and posteriorly, complicating not only detailed examination of their structure but also overall identification. Acoustic shadowing from adjacent organs significantly reduces image quality, resulting in small lesions not being visualized. Furthermore, Lee et al. (2021) emphasize that traditional ultrasound algorithms (e.g., IOTA Simple Rules) are not always reliable when examining pregnant patients [10].
After delivery, the uterus rapidly decreases in size, making the uterine appendages more accessible for visualization. Therefore, in most cases, ovarian masses were detected during pelvic ultrasound examinations prior to discharge from the maternity hospital. In the postpartum period, due to the pronounced mobility of the abdominal and pelvic organs caused by the processes of uterine involution, complications may arise, including torsion of the ovarian mass, as demonstrated in their observation by Kadrekar and Patel (2024) in a patient with a large mucinous cystadenoma [11], however, according to the data of the present study, no complications were identified in the postpartum period.
The distribution of histological types of ovarian space-occupying lesions according to the results of this study also corresponds to the data presented in the literature: mature teratomas were detected in 8/45 (17.8%) cases (42.1% of the removed lesions), serous cystadenomas in 4/45 (8.9%) cases (21.05% of the removed lesions), endometrioid cysts in 4/45 (8.9%) cases (21.05% of the removed lesions), and paraovarian cysts in 3/45 (6.7%) cases (15.8% of the removed lesions).
The patient management tactics were in accordance with international recommendations [12]: surgical treatment involving removal of the ovarian mass during pregnancy was performed when clinical and laboratory symptoms indicating the development of complications appeared (in the present observation, torsion of the pedicle of the mass occurred in 2/45 (4.4%) cases and hemorrhage into the cyst occurred in 1/45 (2.2%) cases), as well as when the mass was detected during cesarean section.
According to the literature, ovarian masses with a diameter of < 5 cm are capable of spontaneous regression without surgical intervention [8, 13], however, according to the data of the present study, in 24/45 (53.3%) patients for whom dynamic observation was chosen as the management tactics, the diameter of the ovarian mass was ≥ 5 cm in diameter (maximum 6 cm), but they also experienced complete spontaneous regression. However, it should be noted that in these cases, the ovarian masses were unilateral and represented thin-walled, unilocular avascular cysts with anechoic contents. This confirms the notion that ovarian masses, despite their size, with typical benign features and the absence of complications, have the potential for spontaneous regression.
CONCLUSION
This study demonstrated the insufficient information content of the standard ultrasound screening protocol during pregnancy, emphasizing the need for a thorough examination of the uterine adnexa anatomy early in gestation (primarily in the first trimester), while they are typically located and accessible for visualization.
Including mandatory assessment of ovarian size and structure in the standard prenatal ultrasound protocol appears to be a reasonable and clinically significant approach to improving obstetric practice in the context of preventing pregnancy complications and achieving favorable maternal and perinatal outcomes.

About the authors

Irina Ignatko

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: ignatko_i_v@staff.sechenov.ru
ORCID iD: 0000-0002-9945-3848
SPIN-code: 8073-1817
Scopus Author ID: 15118951800

Член-корреспондент РАН, профессор, заведующий кафедрой акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Ksenia Yanukyan

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: ks24101@yandex.ru
ORCID iD: 0009-0008-4745-396X

аспирант кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

Russian Federation, 119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Vladimir Pashkov

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: pashkov_v_m@staff.sechenov.ru
ORCID iD: 0000-0003-3768-7822
SPIN-code: 7572-4791

профессор, профессор кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

Russian Federation, 119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Vladimir Lebedev

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: lebedev_v_a@staff.sechenov.ru
ORCID iD: 0000-0002-3302-5533
SPIN-code: 6784-4855

профессор, профессор кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

Russian Federation, 119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Elena Timokhina

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: timokhina_i_m@staff.sechenov.ru
ORCID iD: 0000-0001-6628-0023
SPIN-code: 4946-8849

профессор, профессор кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Vera Belousova

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: belousova_v_s@staff.sechenov.ru
ORCID iD: 0000-0001-8332-7073
SPIN-code: 6026-9008

доцент, профессор кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

Russian Federation, 119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Irina Bogomazova

First Moscow State Medical University named after I.M. Sechenov of the Ministry of Health of the Russian Federation (Sechenov University)

Author for correspondence.
Email: bogomazova_i_m@staff.sechenov.ru
ORCID iD: 0000-0003-1156-7726
SPIN-code: 9414-1218
Scopus Author ID: 57191968287

Associate Professor, Associate Professor of the Department of Obstetrics, Gynecology and Perinatology of the N.V. Sklifosovsky Institute of Clinical Medicine

Russian Federation, 119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Elena Pitskhelauri

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: pitskhelauri_e_g@staff.sechenov.ru
ORCID iD: 0000-0002-9634-1541
SPIN-code: 9593-7483

доцент, доцент кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

Russian Federation, 119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Tatyana Kuzmina

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: kuzmina_t_ye@staff.sechenov.ru
ORCID iD: 0000-0001-9649-5383
SPIN-code: 7198-1382

доцент, доцент кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

Russian Federation, 119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Anastasia Churganova

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: churganova_a_a@staff.sechenov.ru
ORCID iD: 0000-0001-9398-9900
SPIN-code: 3872-7167

доцент, доцент кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

Russian Federation, 119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Irina Fedyunina

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: fedyunina_i_a@staff.sechenov.ru
ORCID iD: 0000-0002-9661-5338
SPIN-code: 1929-5879

доцент кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Madina Kardanova

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: kardanova_m_a@staff.sechenov.ru
ORCID iD: 0000-0002-4315-0717
SPIN-code: 3895-9666

доцент кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

Russian Federation, 119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Svetlana Pesegova

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: pesegova_s_v@staff.sechenov.ru
ORCID iD: 0000-0002-1339-5422
SPIN-code: 8891-9490

ассистент кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

Russian Federation, 119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

Anastasia Samusevich

Первый Московский государственный медицинский университет имени И.М. Сеченова Министерства здравоохранения Российской Федерации (Сеченовский Университет)

Email: samusevich_a_n@staff.sechenov.ru
ORCID iD: 0000-0002-1102-2737
SPIN-code: 6765-3839

ассистент кафедры акушерства, гинекологии и перинатологии Института клинической медицины имени Н.В. Склифосовского

Russian Federation, 119991, Российская Федерация, г. Москва, ул. Трубецкая, д. 8, стр. 2

References

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