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Matern Child Health J (2015) 19:850858 DOI 10.1007/s10995-014-1583-z
Short Interpregnancy Interval Associated with Preterm Birth in US Adolescents
Lina M. Nerlander William M. Callaghan
Ruben A. Smith Wanda D. Bareld
Published online: 26 July 2014 Springer Science+Business Media New York (outside the USA) 2014
Abstract A short interpregnancy interval (IPI) is a risk factor for preterm delivery among women of reproductive age. As limited data exist concerning adolescents, we aimed to examine the association between short IPIs and preterm birth among adolescents using a majority of US births. Using 20072008 US natality data, we assessed the relationship between IPIs \3, 35, 611, and 1217 months and moderately (3236 weeks) and very (\32 weeks) preterm singleton live births among mothers\20 years, relative to IPIs 1823 months. Adjusted odds ratios (aORs) and 95 % condence intervals (95 % CIs) adjusted for maternal race, age, previous preterm deliveries, marital status, smoking and prenatal care were determined from a multivariable multi-nomial logistic regression model. In 20072008, there were 85,077 singleton live births to women aged\20 who had one
previous live birth, 69 % of which followed IPIs B18 months. Compared with IPIs 1823 months, short IPIs were associated with moderately preterm birth for IPIs \3 months (aOR 1.89, 95 % CI 1.702.10), 35 months (aOR 1.33, 95 % CI 1.221.47), and 612 months (aOR1.11, 95 % CI 1.021.21). IPIs\3 and\6 months were also associated with very preterm birth, with aORs of 2.52 (95 %
CI 1.983.22) and 1.68 (95 % CI 1.352.10) respectively. Many adolescent mothers with repeat births have short IPIs, and shorter IPIs are associated with preterm birth in a dose-dependent fashion. Increasing adolescent mothers use of effective contraception postpartum can address both unintended adolescent births and preterm birth.
Keywords Interpregnancy interval Preterm birth Teen
pregnancy Birth intervals Premature birth Pregnancy in
adolescence Contraception Rapid repeat pregnancy
Introduction
The teen birth rate in the United States remains among the highest in the developed world [1]. Between 300,000 and 400,000 children are born annually to adolescent mothers aged 19 or below in the US, with lower rates in recent years [25]. Around 18 % are repeat births [25]. Adolescents have a higher risk of preterm birth, with 19.0 and 12.7 % of all births being preterm in\15-year olds...