Fetal adnexal cysts present unique challenges during pregnancy, requiring careful management strategies to mitigate risks throughout gestation and delivery. We present the case of a 35-year-old G4P2 patient, referred to our center for a large adnexal cyst confirmed by ultrasound (US) and fetal MRI, with a calculated volume of 210 mL. Given the cyst's size and the family's strong preference for vaginal delivery (VD), US-guided aspiration was performed at 356/7 weeks, followed by an uncomplicated spontaneous VD at 372/7 weeks. Two weeks postpartum, the ovarian cyst re-accumulated, requiring laparoscopic-assisted cystectomy in a torsed but viable left ovary. This case demonstrates the importance of individualized prenatal care, where clinical decisions balance parental preferences with medical risks. Maximizing the opportunity for vaginal birth was a top priority for the family, and the successful reduction of the cyst's size through percutaneous aspiration minimized the risk of abdominal dystocia and allowed for a safe VD. We review relevant literature, emphasizing the need for further research to refine fetal intervention criteria and improve outcomes for such cases.

All listed authors made substantial contributions to this manuscript. Specifically, G.B. and A.A.S. contributed to the conception and design of the manuscript. G.B. conducted the data acquisition. R.A.D. and T.L.B. assisted with the interpretation of data. All authors assisted with the drafting of the manuscript and reviewed and approved the final submitted version.

Verbal informed consent was obtained from the patient for the publication of this case report, including the use of de-identified data and imaging.

Received: 22 January 2025

Accepted: 28 February 2025

Accepted Manuscript online:
19 March 2025

Article published online:
10 April 2025

© 2025. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

Thieme Medical Publishers, Inc.
333 Seventh Avenue, 18th Floor, New York, NY 10001, USA