THE PREDICTIVE VALUE OF FIRST-TRIMESTER EMBRYONIC HEART-RATES IN INFERTILITY PATIENTS

Objective: To analyze whether first-trimester embryonic (fetal) heart rates (FHR) are useful in predicting pregnancy outcome for infertility patients. Methods: Patients in a university-based reproductive endocr inology and infertility practice were studied prospectively. Infertile women who achieved clinical pregnancy underwent first-trimester trans vaginal sonographic evaluation, and FHR in patients achieving viable p regnancies were compared with those experiencing fetal loss. Results: Overall, 99 pregnancies reached viability and 17 resulted in fetal los s before 20 weeks' gestation. Patient age, methods of conception, and number of previous fetal losses did not differ significantly between t he two groups. A significant correlation (r = .70, P < .001) was found between increasing FHR levels and advancing gestational age in patien ts with viable pregnancies and, although to a weaker extent, patients who miscarried (r = .52, P < .05). A significantly higher number of vi able pregnancies, compared with fetal losses, had FHR falling within o ne (70.7% compared with 41.2%, P < .025) and two (99.0% compared with 64.7%, P < .001) standard deviations of the mean for viable pregnancie s at corresponding gestational ages. The majority of FHR of failing pr egnancies fell below the individual reference ranges. Conclusion: Firs t-trimester FHR can help predict pregnancy outcome for infertility pat ients. Women with FHR outside the reference range from the mean for vi able pregnancies at corresponding gestational ages may be at risk for eventual pregnancy loss. (C) 1997 by The American College of Obstetric ians and Gynecologists.