Antenatal origins of individual differences in heart rate

This study examines prenatal-to-postnatal stability in heart rate and varia bility from mid-gestation through the first year of life. Fetal heart rate data were collected from 52 healthy fetuses at 24 30, and 36 weeks gestatio n, and again at 2 weeks and 12 months of age. Fetal heart rate measures wer e stable during gestation and positively associated with neonatal and infan t measures. Maternal pulse rare and oxygen saturation were moderately assoc iated with fetal heart rate. Together fetal cardiac (heart rate and variabi lity) and maternal physiologic measures (blood pressure and oxygen saturati on) explained 40 and 48% of the variance in heart rate and variability, res pectively, at I year of age. These common measures of individual difference s in autonomic function are enduring characteristics that originate during fetal development. (C) 2000 John Wiley & Sons, Inc. Dev Psychobiol 37: 221- 228, 2000.