RESUMO
OBJECTIVE: To establish updated placental percentile nomograms in a large North American population for singleton and twin gestations for the use of researchers and clinicians. STUDY DESIGN: Data was extracted from our computerized registry; McGill Obstetrics and Neonatal Database (MOND). The registry includes all the obstetrical data on all deliveries at the McGill University, including placental weight, placental pathologies, maternal and perinatal complications. 20,635 singleton deliveries and 527 twin deliveries were included. Placental weight, gestational age at delivery, birth weight and gender were retrieved. Tables and figures for the 3rd,10th,25th, 50th, 75th 90th, and 97th percentile of placental weight by gestational age, placental weight by birth weight and placental to birth weight ratio by gestational age were produced. RESULTS: Tables and figures are presented for placental percentiles curves according to gestational age, gestational weight and gender for singleton and twin deliveries. In addition, tables and figures are presented for the ratio of placental weight to birth weight. CONCLUSIONS: Population percentile curves have been produced for placental weight and for the ratio of placental weight to birth weight to for singleton and twin deliveries.