A retrospective analysis of ovarian endometriosis during pregnancy

Abstract

Objective: To clarify the frequency of pregnancy complicated by ovarian endometriosis and to investigate the size change and outcome of ovarian endometriosis during pregnancy.

Design: Retrospective study.

Setting: Departments of obstetrics and gynecology of the Osaka University and Izumiotsu Municipal Hospitals of Osaka, Japan.

Patient(s): Women who delivered between 1996 and 2007.

Intervention(s): None.

Main outcome measure(s): The frequency of pregnancies complicated by ovarian endometriosis and the size change of the lesions during pregnancy.

Result(s): The frequency of ovarian endometriosis-complicated pregnancy has almost quadrupled over the last 12 years, to become the most common adnexal mass detected during pregnancy; it was 0.14% (five cases among 3558 deliveries) during the 6-year period from 1996 to 2001, but has increased to 0.52% (19 cases among 3599 deliveries) during the 6-year period from 2002 to 2007, a statistically significant increase of 3.8-fold. Among 25 ovarian endometriotic lesions observed during pregnancy in 24 women (one case had two lesions), the size of the cyst decreased in 13 lesions (52%), went unchanged in 7 (28%), and increased in 5 (20%), that demonstrated decidualization, abscess and rupture.

Conclusion(s): Ovarian endometriosis during pregnancy can be safely observed conservatively; however, further investigation is required to predict the occurrence of abscess formation or rupture of ovarian endometriosis, and to distinguish the enlargements due to malignant transformation from those related to decidualization.