Association between maternal hypertensive disorders, fetal growth and childhood learning outcomes

Both small for gestational age (SGA) birthweight and pregnancies complicated by maternal hypertension (HTN) are independently associated with poorer childhood learning outcomes, however the relative contribution of each remains unknown.

A retrospective cohort was created in which 2014-2017 third grade Rhode Island Department of Education data were linked to Rhode Island Department of Health birth certificate data. The study population was composed of non-anomalous, singleton births between 22- and 42-weeks' gestation. Reading and math proficiency were compared among four groups: 1) appropriate for gestational age (AGA) and no maternal HTN (referent), 2) AGA with HTN, 3) SGA without HTN and 4) SGA with HTN.

Bivariable and multivariable log-binomial regression were used to examine the association between subject proficiency and pregnancy complication, adjusting for potential confounders.

Of the 23,097 who met inclusion criteria, 1004 (4%) were AGA with HTN, 1575 (7%) were SGA without HTN and 176 (1%) were SGA with HTN. Overall, when adjusted for maternal age, gestational age, sex and socioeconomic factors, only children born SGA without HTN had reduced reading proficiency (relative risk (RR) 0.86 95% confidence interval (CI) 0.78, 0.92) and math proficiency (RR 0.88 95% CI 0.82, 0.94) compared to children born AGA without HTN.

In a diverse, statewide cohort, only SGA without HTN was associated with lower reading and math proficiency compared to uncomplicated pregnancies. This suggests that only decreased fetal growth from causes other than HTN is associated with risk of poorer school-age outcomes, and has implications for early resource allocation.