The incident of ovarian cyst is about 1 in 100- 10000 pregnancies. Most are diagnosed incidentally, during a routine obstetric scan. The majority of these masses resolve by the second trimester, allowing a conservative management. Is there a cause for concern?
The ovarian cyst is broadly classified into functional (luteal cyst) and pathological groups (endometriosis, cystadenoma, dermoid cyst, malignancy). Most pregnancy related ovarian cyst, are of corpus luteal and follicular cyst origin. By 16-20 weeks, up to 96% of masses resolve spontaneously.
The persistent ovarian cyst in pregnancy is associated with significant sequelae such as torsion, leaking, rupture, infection and malignancy (1-8%). The common presentation is pain and occasionally obstructed labor. These complications may result in the need for emergency surgical intervention and increased risk of adverse outcome.
Masses that persist longer may warrant further work-up for potential neoplastic disease . Surgery may be indicated when cyst cause pain and discomfort, or with rapid growth on serial scan. Other factors that influence this decision include the size of the cyst, gestational age, available resource and patient preference.
If surgery is indicated, it is generally done in the second trimester, usually 16-20weeks. However, this surgery is associated with a 22% risk of preterm labor. The fetal outcome is closely related to the fetal weight and gestational age.