Mortality risk of small infants varies with their mother's birthweight and race.
We analysed a transgenerational linked birth file to investigate the relationship between maternal birthweight and infant birthweight-specific mortality risk for white and African American infants. Birth records of 267,303 infants born between 1989 and 1991 were linked to records of their mothers, born between 1956 and 1976, and to their own death certificates for those dying in the first year. The means, standard deviations and z-scores were calculated for each race- and generation-specific birthweight distribution. Investigators then analysed the mortality of very small infants (birthweight at least two standard deviations below their mean) for three maternal birthweight categories. Over half of the infant deaths involved births with weights more than two standard deviations below the relevant population mean birthweight (comprising 4.2% of white and 6.9% of African American births respectively). African American infants experienced higher mortality rates at all levels of standardised birthweight, from z-scores of -3 to +3. The relative risk of mortality associated with very small infant size was less for infants delivered to smaller birthweight mothers when compared with those whose mothers were average sized or large at birth. This differential effect was confined to neonatal deaths and was more prominent in the white subpopulation.
Owusu-Ansah
Albert K
AK
Division of Neonatology, John H. Stroger, Jr. Hospital of Cook County, Chicago, IL 60612, USA.
David
Richard J
RJ
D001741:Black or African American / Q000706:statistics & numerical data; D001719:Birth Certificates; D001724:Birth Weight; D003644:Death Certificates; D005260:Female; D006801:Humans; D007223:Infant; D007226:Infant Mortality / Q000208:ethnology; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D009035:Mothers; D012307:Risk Factors; D044465:White People / Q000706:statistics & numerical data