Auscultation of the fetal heart in early pregnancy.

INTRODUCTION: Auscultation of the fetal heart is a common event in antenatal care, in early pregnancy it may be associated with false negative results, which require ultrasound scan to confirm fetal viability. METHODS: We studied 197 women in early pregnancy to determine the gestational age at which the fetal heart can be reliably identified and the factors which determined the accuracy of the test. RESULTS: The proportion of successful auscultations increased with advancing gestation (p <0.001). There was no effect of maternal body mass index or the level of midwifery experience. CONCLUSION: For a sensitivity of 90%, the fetal heart should be auscultated after 13 week gestation. If a sensitivity of 80% is acceptable the fetal heart can be auscultated after 12 + 1 week gestation.