Long-term prognosis of pregnancies complicated by slow embryonic heart rates in the early first trimester.

Abstract

slow embryonic heart rate in the early first trimester is associated with a poor short-term prognosis. [1][2][3][4][5][6][7] In particular, rates below 100 bpm prior to 6.3 weeks' gestation and below 120 bpm between 6.3 weeks and 7.0 weeks carry an elevated risk of death by the end of the first trimester. The risk of embryonic death is close to 100% when the rate is less than 80 bpm below 6.3 weeks or less than 100 bpm between 6.3 weeks and 7.0 weeks. The risk declines progressively with increasing heart rates until it plateaus for heart rates over 100 bpm at less than 6.3 weeks or 120 bpm between 6.3 weeks and 7.0 weeks. Slow embryonic heart rates at gestational age 7 weeks or less are associated with high risk of first trimester death. Our goal was to determine the prognosis for those embryos with slow early heart rates who survive the first trimester. We prospectively recorded embryonic heart rates for all obstetrical sonograms obtained on singleton pregnancies at or before 7.0 weeks' gestation since 1993. We collected information about pregnancy outcome, including date of live birth or in utero death and presence and nature of congenital anomalies. First trimester survival rate was 61.6% among 531 embryos with slow early heart rates (<100 bpm at ≤6.2 weeks, <120 bpm at 6.3 to 7.0 weeks), lower than the survival rate of 91.5% among 1501 embryos with normal heart rates (p < 10 -8 , Fisher's exact test). Among 299 pregnancies in which the early heart rate was slow and the fetus was still alive at the end of the first trimester, 277 (92.6%) resulted in liveborn infants without congenital anomalies, similar to the frequency of 95.1% in cases with normal early heart rates (p > 0.10, Fisher's exact test). Structural and chromosomal anomalies, however, occurred more than twice as frequently in cases with slow early heart rates: 5.4% (16 of 299) of the first trimester survivors with slow early heart rates proved to have anomalies, as compared to 2.4% (31 of 1281) of cases with normal early heart rates (p < 0.05, Fisher's exact test). In conclusion, a pregnancy in which the embryo has a slow heart rate at or before 7.0 weeks' gestation and which continues beyond the first trimester has a high likelihood (>90%) of resulting in a liveborn neonate without congenital anomalies. Embryos with slow early heart rates do, however, have a greater risk of having anomalies than embryos with normal early heart rates.

The effect of drugs with ion channel‐blocking activity on the early embryonic rat heart

“…first trimester have been associated with a markedly increased risk in spontaneous abortion (Benson and Doubilet, 1994;Benson, 1995, 2005;Doubilet et al, 1999). In this study, the concentration of a drug causing a 20% reduction in the embryonic heart rate (EC 20 ) was chosen for drug comparisons.…”

Birinci Trimester Ultrasonografi Incelemesi

“…Embriyo>7 mm olduğu zaman kardiyak aktivite mutlaka izlenmelidir [2]. Kalp hızında yavaşlama (5-7. haftalarda<100/dk atım) kötü prognoz göstergesi olup gebelik kaybıyla iliş-kilendirilmektedir [15]. Ancak bu bulgu kesin tanı koymak için kullanılmaz, takip gerektirir.…”

First-Trimester Ultrasound: Early Pregnancy Failure

“…A slow EHR (<90 bpm) when observed at 6-7 weeks gestation, carries a risk of fi rsttrimester pregnancy loss of about 25 % in several studies even in cases where the EHR is in the normal range at an 8-week follow-up exam [ 64 , 65 ]. An increased EHR (greater than 2 standard deviations above the mean) has not been associated with pregnancy loss [ 64 ].…”