Embryonic heart rate as a predictor of first-trimester pregnancy loss in infertility patients after in vitro fertilization.

OBJECTIVE

To determine if embryonic heart rate (EHR) is useful to predict first-trimester pregnancy outcome after in vitro fertilization (IVF).

DESIGN

Retrospective analysis.

SETTING

University-based infertility center.

PATIENT(S): Six hundred fifty patients who completed IVF with singleton implantations from October 2002 to September 2006 were identified.

INTERVENTION(S): Transvaginal sonography at 4-6 weeks' embryonic age.

MAIN OUTCOME MEASURE(S): Embryonic heart rate at 4-6 weeks' embryonic age and first-trimester pregnancy outcome.

RESULT(S): Ninety-five patients (14.6%) spontaneously aborted, and 555 (85.4%) patients had clinical pregnancies beyond the first trimester. Groups were similar regarding gravidity, parity, embryos transferred, embryonic age at time of sonogram for EHR, and infertility diagnosis. Mean maternal age was significantly higher in the group that spontaneously aborted. Mean EHR was significantly lower in the group that spontaneously aborted. Multivariate logistic regression confirmed the best predictors of poor pregnancy outcome: increasing maternal age (odds ratio [OR] 1.18) and lower EHR (OR 1.07).

CONCLUSION(S): Embryonic heart rate, independent of maternal age, is useful to help predict first-trimester pregnancy prognosis after IVF. Infertility patients with a low EHR (<or=110 bpm) at 4-6 weeks' embryonic age should be counseled that they are at increased risk for first-trimester pregnancy loss.