The role of ultrasonography in the detection and management of adnexal masses during the second and third trimesters of pregnancy

OBJECTIVE: Our purpose was to determine the effect of routine second-trimester and third-trimester ultrasonographic examinations on the prevalence of detectable and operable adnexal disease. STUDY DESIGN: The study group consisted of 7996 pregnant women between 13.0 and 42.8 weeks' gestation. The size and architectural pattern of any detectable adnexal masses were noted. RESULTS: A total of 328 of the 7996 (4.1%) women in the study group had 335 ultrasonographically detectable adnexal masses; 309 of the masses were unilocular or had a single thin septation and 26 were architecturally complex. Of the ovarian cysts 252 of 309 (81.6%) had a mean diameter < 3.0 cm; 60% of the 252 patients in this subgroup had serial ultrasonographic examinations; 43 of the unilocular cysts resolved, and 17 have persisted for up to 2 years. There is a statistically significant trend toward decreasing frequency of ovarian cysts with increasing gestational age (chi(2) for linear trend; P <.00001). Eighteen of the 7996 had an exploratory laparotomy(1 operation per 444 deliveries) during pregnancy or in the postpartum period. In addition, 1 patient had a paratubal cyst excised at the time of postpartum bilateral tubal ligation. Pathologically confirmed lesions included 8 benign cystic teratomas, 3 mucinous cyst adenomas, 2 paratubal cysts, 2 corpus lutea, 1 serous cystadenoma, 1 follicular cyst, 1 endometrioma, and 1 ovarian fibroma. CONCLUSION: Ovarian cysts are found in 4.1% of second-trimester and third-trimester obstetric ultrasonographic examinations. Most ultrasonographically detectable cysts are < 3.0 cm in diameter and usually resolve. The frequency of exploratory laparotomy for adnexal disease is not significantly different from that in reports before the widespread use of obstetric ultrasonography.