Diabetes, birth weight, and academics: higher birth weights are associated with better academic outcomes in children, except when the mother has diabetes during pregnancy.
Uncontrolled preexisting or gestational diabetes during pregnancy is linked to increased adverse maternal and infant outcomes. Gestational weight gain above guidelines is associated with a higher risk of cesarean delivery and larger birth weight for gestational age. A recent study evaluated the link between birth weight and school achievement in children born to mothers with diabetes.
The whole-of-population study included 73,642 children and was done by assessing perinatal data with children’s school assessments from the National Assessment Program-Literacy and Numeracy (NAPLAN). This data included reading, writing, spelling, grammar, and numeracy for third grade students. Students were characterized as performing above national minimum standards or not. The birth weight for gestational age was compared to Australian standards. This study included women with and without diabetes during pregnancy and did not separate gestational diabetes from preexisting diabetes.
Body weight for gestational age was categorized as low (<20th), middle (20-79th), and highest (>80th) quintiles. Log-Poisson regression models were used to calculate risk and adjustments were made for potential confounders. Infants born to women with and without diabetes had a mean birth weight of 3,419 grams and 3,376 grams.
Results show that in women without diabetes, infants born with higher body weights for gestational age (>80th percentile) had better academic outcomes, and lower weights for gestational age had worse school outcomes. In women without diabetes, children born with low body weights for age had a 17% higher risk of having poor spelling capabilities.
Conversely, in women with diabetes who gave birth to infants with high body weight for gestational age, the children were at higher risk for poor academic scores. Specifically, infants born to mothers with diabetes, with a high body weight for gestational age, had a 38% higher risk of poor spelling performance. Overall school assessments were also poorer for infants born in this category. It was also noted that births at age 40-41 weeks’ gestation were optimal for school achievement.
This large whole-of-population study is less likely to have recall and selection biases compared to cohort studies and was adequately powered. Although this study adjusted for confounders, maternal body mass index was not collected. Other studies showed this did not alter the point estimates. Data shows that adjusting for maternal BMI is more important when the outcome involves child weight instead of education. The perinatal database did not include information on maternal diabetes control.
This study emphasized the need for providers to closely manage gestational weight gain in patients with diabetes. Larger than normal fetal sizee may indicate hyperglycemia and should be controlled with optimization of blood glucose. It is suggested to closely monitor fetal size and adjust diet and diabetes management as needed to help reduce large for gestational age births.
- Infants who are large for gestational age and born to mothers with diabetes are at an increased risk to perform poorly in school.
- Births at age 40-41 weeks’ gestation were optimal for school achievement.
- In women without diabetes, infants born with higher body weights for gestational age had better academic outcomes
Smithers, Lisa G., et al. “Diabetes During Pregnancy Modifies the Association Between Birth Weight and Education: A Whole-of-Population Study.” Diabetes Care, 2019, p. dc190958., doi:10.2337/dc19-0958.
LifeCycle Project-Maternal Obesity and Childhood Outcomes Study Group. “Association of Gestational Weight Gain With Adverse Maternal and Infant Outcomes.” JAMA, American Medical Association, 7 May 2019, jamanetwork.com/journals/jama/fullarticle/2732571.
Kassey James, Pharm.D.Candidate, LECOM School of Pharmacy