Significance of fetal heart rate by vaginal ultrasound in the early pregnancy.

Cha, Dong Hyun; Lee, Yoon Ho; Kim, Jong Seok; Suh, Seung Hyun; Park, Byung Joo; Kim, Jong Wha

Obstet Gynecol Sci > Volume 43(7); 2000 > Article

Original Article

Korean Journal of Obstetrics & Gynecology 2000;43(7):1176-1180.
Published online January 1, 2001.

Significance of fetal heart rate by vaginal ultrasound in the early pregnancy.

Dong Hyun Cha, Yoon Ho Lee, Jong Seok Kim, Seung Hyun Suh, Byung Joo Park, Jong Wha Kim

Abstract

OBJECTIVE
Fetal heart rate in embryos(6-8 gestational weeks) have been significantly related to fetal outcome, but have rarely been studied. We attempted to identify fetal heart rate during 6-8 gestational weeks. Our purpose was to determine the lower limit of the heart rate associated with a favorable outcome and to evaluate the prognosis for those embryos with slow heart rates in early period. METHODS: We prospectively studied 798 singleton pregnancies between Jul. 1997-Dec. 1999 visiting our hospital. Gestational age was calculated from the beginning of the last menstrual period in the case of regular cycle and was confirmed by the crown-rump length. Other cases were measured by crown-rump length or mean gestational sac diameter. Color doppler sonography was used to calculate the fetal heart rate in beats per minute as the mean of 3 waves. RESULTS: Mean fetal heart rate (+/-SD) were 114.08+/-15.40 bpm for group 1, 126.49+/-18.78 for group 2, 139.83+/-19.92 for group 3, and 149.58+/-23.34 for group 4(p<0.001). Prognosis in the first trimester improved as heart rate increased to 100 bpm in group 1 and 120 bpm in group 2. In group 3 and 4, most of fetus with heart rates below 110 bpm died. CONCLUSIONS: The fetal heart rate during 6-8 gestational weeks is associated with fetal outcome at the end of the first trimester and we can identify the fetuses that are in risk.

Key Words: Transvaginal ultrasound, Fetal heart rate, Early pregnancy, Fetal outcome