Trends in Adolescent Rapid Repeat Pregnancy in Canada.

Objective: Rapid repeat pregnancy (RRP), a birth occurring within 33 months of a previous birth, is associated with adverse neonatal outcomes. RRP occurs among 25%-35% of adolescents who become pregnant. The current study examines trends in and outcomes of adolescent RRP in the Canadian context.

Methods: Using population-based data from the Discharge Abstract Database, we linked maternal and newborn records from labour and delivery hospitalizations across Canada (excluding Québec) from fiscal years 2004/2005 to 2014/2015. Women were included if they were aged younger than 20 years at the index birth event and delivered an infant during the study period. We assessed absolute rates of RRP and differences between groups using χ tests. Linear tests for trend assessed change over time. Conditional logistic regression models assessed odds of adverse maternal and neonatal outcomes in RRPs compared with first pregnancies.

Results: Overall, we captured 67 957 adolescent pregnancies during the study period. Of these, 32.9% (95% CI 32.5%-33.2%) had an RRP. Rates of RRP were higher among 18- to 19-year-olds (34.1%; 95% CI 33.6%-34.5%) than 15- to 17-year-olds (30.4%; 95% CI 29.7%-31.0%). There was substantial variation in RRP rates across provinces and territories, from 24.5% (95% CI 23.6%-35.6%) in British Columbia to 47.3% (95% CI 46.1%-48.4%) in Manitoba. Generally, the odds of maternal or neonatal morbidity were similar in second pregnancies. However, adolescents had decreased odds of having a small-for-gestational-age infant in their second pregnancy (P < 0.001), affecting 0.4% (95% CI 0.3%-0.7%) of second pregnancies.

Conclusions: Adolescents who experience a pregnancy are at high risk of experiencing an RRP; however, odds of maternal and neonatal morbidity were similar in second and first pregnancies.