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. 2011 Jun;117(6):1279-1287.
doi: 10.1097/AOG.0b013e3182179e28.

Term pregnancy: a period of heterogeneous risk for infant mortality

Uma M Reddy  1 , Vani R Bettegowda, Todd Dias, Tomoko Yamada-Kushnir, Chia-Wen Ko, Marian Willinger
Affiliations

Term pregnancy: a period of heterogeneous risk for infant mortality

Uma M Reddy et al. Obstet Gynecol. 2011 Jun.

Abstract

Objective: To estimate the trend of maternal racial and ethnic differences in mortality for early-term (37 0/7 to 38 6/7 weeks of gestation) compared with full-term births (39 0/7 to 41 6/7 weeks of gestation).

Methods: We analyzed 46,329,018 singleton live births using the National Center for Health Statistics U.S. period-linked birth and infant death data from 1995 to 2006. Infant mortality rates, neonatal mortality rates, and postneonatal mortality rates were calculated according to gestational age, race and ethnicity, and cause of death.

Results: Overall, infant mortality rates have decreased for early-term and full-term births between 1995 and 2006. At 37 weeks of gestation, Hispanics had the greatest decline in infant mortality rates (35.4%; 4.8 per 1,000 to 3.1 per 1,000) followed by 22.4% for whites (4.9 per 1,000 to 3.8 per 1,000); blacks had the smallest decline (6.8%; 5.9 per 1,000 to 5.5 per 1,000) as a result of a stagnant neonatal mortality rate. At 37 weeks compared with 40 weeks of gestation, neonatal mortality rates increase. For Hispanics, the relative risk is 2.6 (95% confidence interval [CI] 2.0-3.3); for whites, the relative risk is 2.6 (95% CI 2.2-3.1); and for blacks, the relative risk is 2.9 (95% CI 2.2-3.8). Neonatal mortality rates are still increased at 38 weeks of gestation. At both early- and full-term gestations, neonatal mortality rates for blacks are 40% higher than for whites and postneonatal mortality rates 80% higher, whereas Hispanics have a reduced postneonatal mortality rate when compared with whites.

Conclusion: Early-term births are associated with higher neonatal, postneonatal, and infant mortality rates compared with full-term births with concerning racial and ethnic disparity in rates and trends.

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Figures

Figure 1
Figure 1
Infant Mortality Rates by Gestational Age among Singleton Live Births: US, 1995 – 2006 * Percent changes in infant mortality rate between 1995 and 2006 were significant at α = 0.05.
Figure 2
Figure 2
Neonatal Mortality Rates by Gestational Age Weeks by Race/Ethnicity: Singletons, US, 2006
See this image and copyright information in PMC

Comment in

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