The placenta, as the vector for all maternal-fetal oxygen and nutrient exchange, is a principal influence on birthweight. Placental weight summarizes laterally expanding growth of the chorionic disc, and villous arborization yielding the nutrient exchange surface. These different growth dimensions alter fetoplacental weight ratio and ponderal index, and thus may modify placental functional efficiency. The placenta may show a range of histopathologies, some of which are also associated with fetal growth restriction. Different fetal intrinsic abilities to compensate for gross and histo-pathology may clarify the imperfect relationships between fetal growth and both intrauterine pathology, and the long-term health risks associated with poor fetal growth.
*Department of Epidemiology, Mailman School of Public Health, Columbia University College of Physicians and Surgeons, New York, New York
†Department of Pathology, Princess Margaret Memorial Hospital, Perth, Western Australia
‡EarlyPath Clinical and Research Diagnostics, Larchmont, New York
Correspondence: Carolyn M. Salafia, MD, MS, Department of Epidemiology, Mailman School of Public Health, Columbia University, 722 West 168th Street, New York, NY 10032. E-mail: email@example.com
*Subjects were a subset of the NCPP. Details of the study have been described elsewhere. Briefly, from 1959 to 1965, women who attended prenatal care at 12 hospitals were invited to participate in the observational, prospective study. At entry, detailed demographic, socioeconomic, and behavioral information was collected by in-person interview. A medical history, physical examination, and blood sample were also obtained. During labor and delivery, placental gross morphology was examined and samples were collected for histologic examination. The children were followed up to 7 years of age. We derived a subset of the NCPP data set from the 41,970 women who gave the first or only singleton live birth. Of these, 36,017 contributed placenta data. Placental morphometry included placental weight, largest and smallest diameters and thickness, measures cording to a standard protocol. Gestational age was calculated on the basis of the last menstrual period in rounded weeks. The sample was further restricted to those with complete data on the 6 placental gross measures described in this chapter, placental weight, and birth weight, of known gestational age between 34 weeks and 42 6/7 (less than 43) completed weeks (N=24,152). Finally, we examined the data for anomalous values. Extreme values could be valid measures or reflect data entry errors. We limited our exclusions to the 0.1% of cases with placental thicknesses <1cm, which has been reported as the average thickness for a disk at 12 gestational weeks [24(B&K)], yielding a final analytic sample of 24,047.