Journal of Ultrasound in Medicine, Vol 9, Issue 12 711-716, Copyright © 1990 by American Institute of Ultrasound in Medicine
Diagnosis of viability in early pregnancy with vaginal sonography
A. Rempen
Department of Obstetrics and Gynecology, University of Wurzburg, Germany.
The detection rate of embryonic heart action using vaginal sonography was
evaluated in 363 normal singleton pregnancies in the first trimester.
Visible cardiac activity was present at the earliest at a gestational age
of 40 days; in addition, the smallest chorionic cavity had a mean diameter
of 9.3 mm, the lowest human chorionic gonadotropin (beta-hCG) concentration
(calibrated against the first international reference preparation) measured
6,770 mIU/mL, the thinnest trophoblast was 1 mm, and the shortest
crown-rump length was 2 mm. Cardiac pulsations were identified in all cases
either at a menstrual age greater than or equal to 46 days, a beta-hCG
greater than or equal to 47,171 mIU/mL, a mean chorionic cavity diameter
greater than or equal to 18.3 mm, or a trophoblast thickness greater than
or equal to 5 mm. The heart rate (mean +/- SD) increased from 110 +/- 8
beats per minute (bpm) at 5 weeks menstrual age to 170 +/- 6 bpm at 9 weeks
and declined thereafter to 159 +/- 3 bpm at 13 weeks. Vaginal sonography
enables a rapid and reliable assessment of embryonic life in early
pregnancy.
