Marie E Thoma1, Lauren M Rossen2, Dane A De Silva1, Margaret Warner3, Alan E Simon4, Susan Moskosky5, Katherine A Ahrens5,6. 1. Department of Family Science, School of Public Health, University of Maryland, College Park, MD. 2. National Center for Health Statistics, Centers for Disease Control and Prevention, Division of Vital Statistics, Reproductive Health Statistics Branch, Hyattsville, MD. 3. National Center for Health Statistics, Centers for Disease Control and Prevention, Division of Vital Statistics, Mortality Statistics Branch, Hyattsville, MD. 4. Environmental Influences on Child Health Outcomes (ECHO) Project Office, Office of the Director, National Institutes of Health, Rockville, MD. 5. Office of Population Affairs, Office of the Assistant Secretary for Health, U.S. Department of Health and Human Services, Rockville, MD. 6. Muskie School of Public Service, University of Southern Maine, Portland, ME.
Abstract
BACKGROUND: Several studies have examined the association between IPI and birth outcomes, but few have explored the association between interpregnancy interval (IPI) and postnatal outcomes. OBJECTIVE: We examined the association between IPI and injury-related infant mortality, a leading cause of postneonatal mortality. METHODS: We used 2011-2015 US period-linked birth-infant death vital statistics data to generate a multiyear birth cohort of non-first-born singleton births (N = 9 782 029). IPI was defined as the number of months between a live birth and the start of the pregnancy leading to the next live birth. Causes of death in the first year of life were identified using ICD-10 codes. Hazard ratios (HR) for IPI categories were estimated using Cox proportional hazards models adjusted for birth order, county poverty level, and maternal characteristics (marital status, race/ethnicity, education, age at previous birth). RESULTS: After adjustment, overall infant mortality (48.1 per 10 000 births) was higher for short and long IPIs compared with IPI 18-23 months (reference): <6, aHR 1.61, 95% CI 1.54, 1.68; 6-11, aHR 1.22, 95% CI 1.17, 1.26; and 60+ months, aHR 1.12, 95% CI 1.08, 1.16. In comparison, the risk of injury-related infant mortality (4.4 per 10 000 births) decreased with longer IPIs: <6, aHR 1.77, 95% CI 1.55, 2.01; 6-11, aHR 1.41, 95% CI 1.25, 1.59; 12-17, aHR 1.25, 95% CI 1.10, 1.41; 24-59, aHR 0.78, 95% CI 0.69, 0.87; and 60+ months, aHR 0.55, 95% CI 0.48, 0.62. CONCLUSION: Unlike overall infant mortality, injury-related infant mortality decreased with IPI length. While injury-related deaths are rare, these patterns suggest that the timing between births may be a marker of risk for fatal infant injuries. The first year postpartum may be an ideal time for the delivery of evidence-based injury prevention programmes as well as family planning services.
BACKGROUND: Several studies have examined the association between IPI and birth outcomes, but few have explored the association between interpregnancy interval (IPI) and postnatal outcomes. OBJECTIVE: We examined the association between IPI and injury-related infantmortality, a leading cause of postneonatal mortality. METHODS: We used 2011-2015 US period-linked birth-infantdeath vital statistics data to generate a multiyear birth cohort of non-first-born singleton births (N = 9 782 029). IPI was defined as the number of months between a live birth and the start of the pregnancy leading to the next live birth. Causes of death in the first year of life were identified using ICD-10 codes. Hazard ratios (HR) for IPI categories were estimated using Cox proportional hazards models adjusted for birth order, county poverty level, and maternal characteristics (marital status, race/ethnicity, education, age at previous birth). RESULTS: After adjustment, overall infantmortality (48.1 per 10 000 births) was higher for short and long IPIs compared with IPI 18-23 months (reference): <6, aHR 1.61, 95% CI 1.54, 1.68; 6-11, aHR 1.22, 95% CI 1.17, 1.26; and 60+ months, aHR 1.12, 95% CI 1.08, 1.16. In comparison, the risk of injury-related infantmortality (4.4 per 10 000 births) decreased with longer IPIs: <6, aHR 1.77, 95% CI 1.55, 2.01; 6-11, aHR 1.41, 95% CI 1.25, 1.59; 12-17, aHR 1.25, 95% CI 1.10, 1.41; 24-59, aHR 0.78, 95% CI 0.69, 0.87; and 60+ months, aHR 0.55, 95% CI 0.48, 0.62. CONCLUSION: Unlike overall infantmortality, injury-related infantmortality decreased with IPI length. While injury-related deaths are rare, these patterns suggest that the timing between births may be a marker of risk for fatal infant injuries. The first year postpartum may be an ideal time for the delivery of evidence-based injury prevention programmes as well as family planning services.
Authors: Carrie K Shapiro-Mendoza; Sharyn E Parks; Jennifer Brustrom; Tom Andrew; Lena Camperlengo; John Fudenberg; Betsy Payn; Dale Rhoda Journal: Pediatrics Date: 2017-06-05 Impact factor: 7.124
Authors: Katherine A Ahrens; Heidi Nelson; Reva L Stidd; Susan Moskosky; Jennifer A Hutcheon Journal: Paediatr Perinat Epidemiol Date: 2018-10-24 Impact factor: 3.980