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. 2014 Jul;124(1):16-22.
doi: 10.1097/AOG.0000000000000345.

A revised birth weight reference for the United States

Elaine L Duryea  1 , Josiah S Hawkins, Donald D McIntire, Brian M Casey, Kenneth J Leveno
Affiliations

A revised birth weight reference for the United States

Elaine L Duryea et al. Obstet Gynecol. 2014 Jul.

Abstract

Objective: To generate birth weight curves based on the obstetric estimate of gestational age as specified in the revised 2003 U.S. birth certificate.

Methods: Using National Center for Health Statistics data from 2011, we constructed birth weight curves for neonates between 24 and 42 weeks of gestation. Curves were developed using the obstetric estimate of gestational age that is included in the revised 2003 U.S. birth certificate, which, when available, incorporates ultrasound dating information. Live-born singleton neonates between 500 and 6,000 g without malformations were included. These curves were compared with curves we generated using 1991 data on which the current national reference of Alexander and colleagues is based, a reference that used only last menstrual period to establish gestational age.

Results: The 1991 curves were based on 3,684,778 U.S. live births and the 2011 on 3,252,011 births. Birth weight percentile values were greater from 28 to 36 weeks of gestation in the 1991 data set. That is, the birth weights for preterm neonates were overestimated when 1991 reference curves were used compared with the proposed 2011 reference. For example, in 1991, a birth weight of 2,000 g was at the 50th percentile between 31 and 32 weeks of gestation, whereas in 2011, a birth weight of 2,000 g now corresponds to the 50th percentile between 33 and 34 weeks of gestation.

Conclusions: Our revised reference curve for the United States provides an updated national reference for birth weight.

Level of evidence: : II.

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References

    1. Lubchenco LO, Hansman C, Dressler M, Boyd E. Intrauterine growth as estimated from liveborn birth-weight data at 24 to 42 weeks of gestation. Pediatrics 1963;32:793–800.
    1. Gonzalez GF, Tapia V. Birth weight charts for gestational age in 63,620 healthy infants born in Peruvian public hospitals at low and at high altitude. Acta Paediatr 2008;98:454–8.
    1. Brenner WE, Edelman DA, Hendricks CH. A standard of fetal growth for the United States of America. Am J Obstet Gynecol 1976;126:555–64.
    1. Williams RL, Creasy RK, Cunningham GC, Hawes WE, Norris FD, Tashiro M. Fetal growth and prenatal viability in California. Obstet Gynecol 1982;59:624–32.
    1. Blidner IN, Mcclemont S, Anderson GD, Sinclair JC. Size-at-birth standards for an urban Canadian population. Can Med Assoc J 1984;130:133–40.