MATERNAL WAIST-TO-HIP RATIO AS A PREDICTOR OF NEWBORN SIZE - RESULTS OF THE DIANA PROJECT

Location of body fat stores, as indicated by waist-to-hip circumferenc e ratio (WHR), affects a variety of metabolic processes in women, and some of these changes could affect fetal growth during pregnancy. We t ested the hypothesis that WHR affects fetal growth among 702 participa nts of the Diana Project, a prospective study designed to identify pre conceptual exposures related to reproductive outcomes. We tested the e ffect of maternal WHR on the outcomes of infant birth weight, length, and head circumference in regressional models that included 16 variabl es such as maternal body mass index, duration of gestation, and pregna ncy weight gain previously related to birthweight. Maternal WHR was re lated to each measure of newborn size. A 0.1-unit increase in WHR pred icts a 120-gm greater birthweight, a 0.2-inch greater length, and a 0. 3-cm greater head circumference. We conclude that WHR is related to fe tal growth and that the effect of WHR on fetal growth may be mediated by metabolic alterations associated with a preponderance of central bo dy fat stores or to other factors closely aligned with WHR. The common finding of an independent effect of prepregnancy BMI on birthweight m ay be largely attributable to maternal WHR.