Visualization of the ovaries in early pregnancy by transvaginal sonography

To determine the frequency of visualization of the ovaries by transvaginal sonography (TVS) in a group of women in early pregnancy and to determine the onset of a decrease in sonographic visualization of the ovaries during this time.

The study population included all patients with an intrauterine pregnancy confirmed by the presence of a yolk sac,embryo, or fetus. The biometric data included crown-rump length and/or gestational sac mean diameter corresponding to < - 14 weeks' gestational age (GA).

The study population included 11,095 women, of whom 1972 (17.8%) had a GA < - 6 weeks, 4665 (42.0%) 6.1 to 8 weeks, 2782 (25.1%) 8.1 to 10 weeks, 1208 (10.1%) 10.1 to 12 weeks, and 468 (4.2%) 12.1 to 14 weeks. At least one ovary was identified in 11,043 women (99.5%), and both ovaries were identified in 10,620 women (95.7%). Only the right ovary was identified in 274 women (2.5%), and only the left ovary was identified in 149 women (1.3%). In 52 women (0.5%), neither ovary was identified. Both ovaries were identified in 1929 pregnancies of < - 6 weeks' GA (97.8%), in 4528 between 6.1 and 8 weeks' GA (97.1%), in 2664 between 8.1 and 10 weeks, GA (95.8%), in 1114 between 10.1 and 12 weeks' GA (92.2%), and in 385 between 12.1 and 14 weeks' GA (82.3%).

Transvaginal sonography achieved an overall visualization of one or both ovaries in 99.5% women with pregnancies of < - 14 weeks, GA. Both ovaries were visualized in 95.7% of women. A significant decline in ovarian visualization occurred after 10 weeks' GA. The results provide reference data on the likelihood of ovarian visualization in early pregnancy.