Neonatal morphometry : relation to obstetric, pediatric, and menstrual estimates of gestational age

• Objective. —To determine gestational age—dependent neonatal morphometrics based on last menstrual periods (LMPs), Ballard examinations, and obstetric estimates of gestational age. Design, Setting, and Participants. —Cross-sectional survey of 38818 live-born neonates at a tertiary care center in Detroit, Mich. Selection Procedures. —Consecutive sample of all viable, structurally normal, singleton neonates delivered at Hutzel Hospital from 1984 through 1991. Measurements/Main Results. —Neonatal weights, lengths, and head circumferences were recorded at birth. Gestational age—dependent morphometrics were based solely on LMPs and compared with those based on obstetric estimates (using LMPs corrected by fetal ultrasound). Ballard examination had an 85.4% concurrence (within 14 days) with obstetric estimates of gestational age, but only a 69.9% ( P Conclusions. —Gestational age—dependent neonatal morphometrics should not be based solely on LMPs. ( AJDC . 1992;146:852-856)