Maternal and Child Health Library

MCH Alert: Focus on Infant Mortality is developed by the Maternal and Child Health Library in collaboration with the National Sudden and Unexpected Infant/Child and Pregnancy Loss Resource Center at Georgetown University. This and past issues are available online at http://www.mchlibrary.info/alert/archives.html and http://www.sidscenter.org/alert/archives.html.

February 27, 2009

1. NETWORK COMPILES RESOURCES AND TOOLS ON LOW BIRTHWEIGHT AND PREMATURITY

Promising Practices for Preventing Low Birth Weight provides an overview of research-based information related to preventing low birthweight (LBW). The issue brief, produced by RAND's Promising Practices Network on Children, Families, and Communities (PPN), defines LBW, presents current trends in LBW in the United States, and discusses what works to prevent LBW. The brief is one of several materials featured on RAND's Low Birth Weight/Prematurity Resources and Tools Web page. The materials meet PPN standards of scientific rigour, objectivity, and user friendliness and include links to databases, fact sheets, screening tools, and seminal reports. The Low Birth Weight/Prematurity Resources and Tools Web page is available at http://www.promisingpractices.net/resources_lowbirthweight.asp?ref=ppntext.

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• Between 1984 and 2004, ASSB infant mortality rates more than quadrupled, from 2.8 to 12.5 deaths per 100,000 live births.
• Between 1984 and 1992, infant mortality attributed to ASSB remained relatively stagnant, ranging from 2.8 to 3.6 deaths per 100,000 live births. Then, between 1992 and 1996, the number of infant deaths attributed to ASSB began to increase. The increase continued through 2004, but was more dramatic after 1996 and onward.
• The proportion of deaths attributed to ASSB and cause unknown increased in 2003 compared with 2004, whereas the proportion of SIDS deaths during this time declined.
• In 2004, the proportion of deaths attributed to ASSB and SIDS deaths both increased, whereas cause-unknown deaths declined.
• Black infants were disproportionately affected by ASSB during 2002-2004, as were male infants.

• The mothers in the HFNY group were significantly less likely to have LBW infants than the mothers in the control group (5.1% vs. 9.8%, respectively).
• Odds for LBW were further reduced for mothers randomized at a gestational age of 24 weeks or less (a group that had the potential to receive prenatal home-visitation services for at least 3 months) and even lower for mothers randomized at a gestational age of 16 weeks or less.
• Black mothers assigned to the HFNY group at 30 weeks’ gestation or less were significantly less likely than black mothers in the control group to deliver LBW babies (3.1% vs. 10.2%, respectively). Although not significant, levels of LBW were noticeably lower for Hispanics in the HFNY group than for those in the control group. There was little difference in LBW among white mothers in the HFNY and control groups.

• A higher proportion of Alaska Native live births, compared with non-Alaska Native live births, occurred among women in high-risk categories.
• Within almost all risk categories, race remained associated with postneonatal mortality.
• Alaska Native mothers had a higher postneonatal mortality rate for all cause-of-death categories evaluated, including preterm birth, infections, and sudden infant death syndrome or asphyxia of unknown etiology.
• Three characteristics explained the majority of the increased risk of postneonatal mortality among Alaska Natives compared with non-native residents of Alaska: (1) higher rates of prenatal alcohol or tobacco use; (2) lower maternal education levels, and (3) greater frequency of a father's name missing on the birth certificate among unmarried mothers. In the final model including all three variables, the disparity largely disappeared (OR 1.3).