Prevalence of Low Birth Weight, Premature Birth, and Stillbirth Among Pregnant Adolescents in Canada: A Systematic Review and Meta-analysis.

Although most studies show that adolescent pregnant women are at a higher risk for adverse birth outcomes, there has been limited research examining this relationship in Canada. This systematic review and meta-analysis investigated the prevalence of low birthweight (LBW), preterm birth (PTB), and stillbirth in Canadian adolescent women compared to adult women. Studies were included if they were primary research and included a sample of adolescent mothers (≤19 years) and adult mothers (≥20 years) who gave birth to singleton infants in Canada. Birth outcomes must have been measured consistently in at least 3 studies for inclusion. Comprehensive electronic literature searches were conducted from database inception until August 2020 in 5 databases. Random effects meta-analysis models were used to estimate pooled odds ratios (pOR) for LBW, PTB, and stillbirth between adolescent and adult pregnant women. Outcomes reported included PTB (8 studies), LBW (6 studies), and stillbirth (3 studies). Compared to adult mothers, adolescent mothers had a 56% increase in the prevalence of LBW (pOR 1.56, 95% confidence interval [CI] 1.24, 1.97), a 23% increase in PTB (pOR 1.23, 95% CI 1.06, 1.42), a 20% increase in stillbirth (pOR 1.20, 95% CI 1.05, 1.37). Heterogeneity, as assessed by I2, was high for LBW and PTB and was low for stillbirth. A subgroup analysis did not remove the high heterogeneity, and some studies did not adjust for confounding variables and were missing information on sociodemographic and behavioral factors. Future research is needed to investigate the mechanisms surrounding these differences by maternal age.