Risk Factors Are Not Very Risky Once a Normal Embryonic Heart Rate is Seen in Early Pregnancy

Objectives To assess first‐trimester prognosis when an early pregnancy sonogram demonstrates a normal embryonic heart rate and to determine how a number of risk factors affect prognosis. Methods Our study population consisted of 6597 first‐trimester scans with gestational age (GA) ≤ 7.0 weeks (all with crown‐rump length [CRL] <10 mm), normal embryonic heart, and known first‐trimester outcome. We recorded GA; CRL; heart rate; first‐trimester outcome; maternal age; presence, absence, and size of subchorionic hematoma; presence or absence of vaginal bleeding; and presence, absence, and size of uterine fibroids. We assessed first‐trimester outcome in the study population and subsets based on the above data. Results First‐trimester outcome was successful in 6030 of the 6597 cases (91.4%). The prognosis was somewhat worse with each of the following risk factors: maternal age ≥35 years, large subchorionic hematoma, and large or multiple uterine fibroids ( P < .02, chi‐squared or Cochran's test for trend, for all of these items). The rate of successful outcome was in the range of 83–88% with each of these risk factors and 93.8% in the absence of any of these factors. Conclusions The presence of a normal embryonic heart rate on an early first‐trimester sonogram is a reassuring finding, indicating a likelihood of good first‐trimester outcome of at least 83% even in the presence of risk factors, and of over 90% in the absence of such factors.