Reliability of transvaginal ultrasound in detecting first trimester pregnancy abnormalities

Abstract

Objective: To evaluate the reliability of transvaginal ultrasound (US) and human chorionic gonadotropin (hCG) levels in detecting early abnormalities and predicting outcome of pregnancy.

Patients: One hundred thirty-two patients were studied, of which 113 had an intrauterine pregnancy and 19 had an ectopic pregnancy (EP).

Results: In 78 with singleton normal pregnancies, US revealed a normal crown-rump length, heart motion, and hCG levels between 1,000 to 107,000 mIU/mL. Of 16 patients with small crown-rump length, heart motion present, and normal hCG levels, 6 aborted and 10 reached term. Thus, 6 of 84 (7.14%) singleton with fetal heart motion aborted. Thirteen with small crown-rump and absent heart motion also aborted. All 8 with an empty gestational sac aborted. In 8, transvaginal US detected four twins, two triplets, and two quadruplets, whereas hCG was not discriminative. Transvaginal US revealed an empty uterus in 19 patients with an EP, whereas serum hCG varied between 37 and 10,500 mIU/mL.

Conclusion: A fetal crown-rump length compatible with gestational age and fetal heart motion seen by transvaginal US can predict a term pregnancy in greater than 90% of patients.