Child Growth and Adolescent Pregnancy: A Longitudinal Sibling Comparison in Peru

Abstract Objectives We aim to quantify the longitudinal growth differences during childhood and early adolescence between siblings born at different maternal ages at delivery (adult vs. adolescent/young). Methods We analyzed data from siblings of the same biological parents of the young cohort from the Young Lives Study in Peru, over 14 of follow-up. Elder siblings were enrolled at one year of age (2002), while younger siblings were enrolled in the third cohort visit (2009). We include elder siblings who were firstborn only and younger siblings who were second-born children. We performed three-level hierarchical models using Gaussian and Poisson families for height for age Z-score (HAZ) and stunting prevalence, respectively, to estimate predicted values at age 2, 5, 8, and 12. We report absolute marginal average contrasts (Φ) between a younger sibling and elder sibling born to adult (25–34 years) and adolescent/young mothers (15–24 years), respectively. Moreover, we adjust the estimate of interest with expected differences between siblings born to mothers in the same maternal age at delivery group. Results The total eligible sample included 310 pairs of siblings, where 85% of index children and 65% of younger siblings were born to adolescent/young women. Contrasts between a sibling from an adult mother and a firstborn index were positive up to age 12 for HAZ (Φ: 0.20 95% CI 0.01, 0.39) and negative for stunting (Φ: −5.09% 95% CI −12.28, 2.10). Expected differences between siblings born to adult mothers in the same delivery age group did not substantially change the findings for HAZ (ΦA: 0.29 95% CI 0.04, 0.53) but increase the magnitude of stunting differences (ΦA: −9.70% 95% CI −15.40, −4.01). Expected differences between siblings born to adolescent mothers decrease the magnitude of both estimates but remain their direction. Conclusions Younger siblings born to adult mothers outperformed older siblings born to adolescent mothers in growth throughout childhood and early adolescence. The long-lasting effects of adolescent pregnancy on their offspring's nutrition ought to be addressed with social policies focused on preventing adolescent pregnancy. Funding Sources None.