New Intrauterine Growth Curves Based on United States Data

The objective of this study was to create and validate new intrauterine weight, length, and head circumference growth curves using a contemporary, large, racially diverse US sample and compare with the Lubchenco curves.

Data on 391 681 infants (Pediatrix Medical Group) aged 22 to 42 weeks at birth from 248 hospitals within 33 US states (1998-2006) for birth weight, length, head circumference, estimated gestational age, gender, and race were used. Separate subsamples were used to create and validate curves. Smoothed percentile curves (3rd to 97th) were created by the Lambda Mu Sigma (LMS) method. The validation sample was used to confirm representativeness of the curves. The new curves were compared with the Lubchenco curves.