The clinical characteristics and sonographic findings of maternal ovarian torsion in pregnancy.

OBJECTIVE: To investigate the incidence, risk factors, and sonographic findings of maternal ovarian torsion in pregnancy.

DESIGN: Retrospective study.

SETTING: Department of Obstetrics/Gynecology of a tertiary referral center.

PATIENT(S): Thirty-three pregnant women with 38 episodes of surgically proven torsion between the years 1993 to 2007.

INTERVENTION: Surgical confirmation and treatment of torsion.

MAIN OUTCOME MEASURE(S): Clinical and sonographic findings of ovarian torsion in pregnancy.

RESULTS: Sixteen (48.5%) pregnancies were conceived by ovulation induction or in vitro fertilization. Twenty-one torsion events occurred in the first trimester (55.3%) versus 13 (34.2%) and 4 (10.5%) in the second and third trimester, respectively. All patients were admitted with abdominal pain, whereas 22 (57.9%) reported nausea/vomiting. The preoperative ultrasound examination showed unilocular ovarian cysts in 15 (39.5%) cases, multicystic ovaries in 14 (36.8%), and normally appearing ovaries in 9 (23.7%) cases. The multicystic ovary was more common in the first trimester torsion, whereas the "normal" appearing ovary was more common in the second and third trimester torsion (47.6% vs. 23.5% and 14.3% vs. 35.3%, respectively). The median duration from admission to surgery was 6 hours (range, 1 hour to 3.7 days), being significantly shorter in the first trimester.

CONCLUSION(S): Ovarian torsion in pregnancy is more common in the first trimester, and induction of ovulation is a major risk factor.