First-trimester fetal growth foretells birthweight

Fetal growth in the first 12 weeks of pregnancy is strongly associated with birthweight for two reasons, according to the findings of a prospective cohort study involving approximately 38,000 pregnancies. The first is the effect that first-trimester size has on the duration of pregnancy, and the second is the effect it has on fetal growth in the second and third trimesters.

The authors of the study also determined that an inverse relationship exists between first-trimester growth and the risk for delivering a small-for-gestational-age infant.

The study underscores that so much about a pregnancy is determined at its earliest stages, often before even the first prenatal physician visit.