Placental weight and its ratio to birthweight in a Ukrainian city.

Abstract

Placental weight and its ratio to birthweight have recently been reported to predict later chronic disease. These fetal growth indicators have been measured in the west for over a century with consistent results when methods of preparation were comparable. We investigated whether recent difficult conditions in the former eastern bloc have altered placental weight or its relationship to other fetal size measures from what has historically been reported. Placentas were obtained from 1621 singleton births of at least 28 weeks gestation in a Ukrainian city during 1993-1994, using a systematic protocol. Maternal characteristics were obtained from questionnaires. Pregnancy complications and birth size measures (infant weight, length, crown-rump length, and head circumference) were abstracted from medical records. We examined relationships of placental weight and ratio to these variables. Placental weight ranged from 100 to 1000 g, with a mean of 470 g. Mean placental ratio was 13.9%. Placental weights increased and ratios decreased with gestational age. Larger ratios were related to larger maternal BMI. Absolute measures of infant size and placental weight were mutually positively correlated. Placental ratio, infant length, and ponderal index (PI) were nearly uncorrelated. Absolute and relative weights of Ukrainian placentas were similar to historical reports, as were their relationships to other infant size indicators. Placental weight ratio (PWR), ponderal index, and infant length measured different birth size dimensions. Placental availability, consistency of placental measurements, and placental ratio's reflection of an independent facet of fetal growth make the placenta a useful research tool.