Measuring Gestational Age in Vital Statistics Data: Transitioning to the Obstetric Estimate.

Beginning with the 2014 data year, the National Center for Health Statistics is transitioning to a new standard for estimating the gestational age of a newborn. The new measure, the obstetric estimate of gestation at delivery (OE), replaces the measure based on the date of the last normal menses (LMP). This transition is being made because of increasing evidence of the greater validity of the OE compared with the LMP-based measure. This report...