Not one but two: cross-sectional associations among repeat pregnancy, maternal mental health and child cognitive outcomes among adolescent and young mothers in South Africa.

Background: Globally, adolescent mothers and their children have poorer health outcomes. However, little is known regarding having multiple children as an adolescent. Analyses explore associations between having multiple versus single children on young mothers' mental health and having a sibling and child development outcomes for their children. Furthermore, maternal age when having a second child (eg, multipara adolescent or multipara adolescent-adult pregnancy) is examined in relation to maternal and child outcomes.

Methods: Data are drawn from a cohort of young mothers (n=1017; 10-24 years) and their children (0-68 months) residing in the Eastern Cape Province, South Africa. Effects of having multiple versus single children on maternal mental health and child cognitive outcomes (assessed using the Mullen Scales of Early Learning) were explored using hierarchical regression models. We examined associations among primipara adolescent motherhood, multipara adolescent motherhood and multipara adolescent-adult motherhood, and child cognitive development scores.

Results: Poor maternal mental health was elevated among multipara mothers. Multipara mothers were more likely to report higher parental stress scores and lower social support scores (p=0.002-0.038). Child cognitive development scores were higher in children born to multipara mothers (those with a sibling (B=6.75, 95% CI 1.00 to 12.51, p=0.021)); younger child age (B=-0.56, 95% CI -0.68 to -0.44, p=<0.001) and formal childcare attendance (B=3.58, 95% CI 0.03 to 7.13, p=0.048) were also identified as positive predictors of higher cognitive development scores. First-born children of multipara adolescent mothers appeared to perform equally well to children born to primipara mothers (children without siblings), while first-born children of multipara adolescent-adult mothers seemed to benefit strongly from having siblings (B=14.31, 95% CI 4.18 to 24.44, p=0.006).

Conclusions: Having multiple children was associated with poorer maternal mental health. Delaying a second pregnancy until adulthood may have benefits, as sibling effects were found to be positively associated with child cognitive development scores. Formal childcare support was associated with positive child outcomes. Findings highlight the need to focus on repeat adolescent pregnancy, improve social, psychological and family planning support among young mothers with a focus on birth timing and spacing, early childhood care provision and support for young families.