Measures of placental growth in relation to birth weight and gestational age.

Fetal growth depends in part on placental growth. The authors tested placental measures derived from digital images for reliability and to evaluate their association with birth weight and gestational age. A total of 628 women recruited into the Pregnancy, Infection, and Nutrition Study, a prospective cohort study of preterm birth in central North Carolina between 2002 and 2004, delivered singleton liveborn infants after 24 completed weeks' gestation. Novel chorionic plate morphometric parameters captured off digital images of the gross placenta were analyzed as estimators of gestational age and birth weight. Without acknowledgment to placental weight, digitally obtained lateral chorionic plate growth measures accounted for 17 percent of gestational age variance and 35 percent of birth weight variance, overall. Chorionic plate measures accounted for 10 percent of birth weight variance beyond that accounted for by placental weight alone. Among preterm births, 34 percent of gestational age variance and 63 percent of birth weight variance were accounted for by lateral chorionic plate growth measures. Intraclass correlation coefficients for the novel digital measures ranged from 0.96 to 0.98. Reliable digital measures of lateral chorionic plate growth estimate birth weight variance more strongly than gestational age, project variance that is not accounted for by placental weight, and project these outcomes to a greater degree in preterm births than at term.