In 6644 singleton pregnancies resulting in live births, the fetal heart rate was measured at 10 to 14 weeks of gestation (median 12). There was no significant association between fetal heart rate and birthweight. These findings demonstrate that if there is an association between fetal heart rate, birthweight and subsequent development of cardiovascular disease the responsible intrauterine insult and/or the adaptive fetal response are not present at 10 to 14 weeks of gestation.