Maternal BMI, not glucose levels, linked to mid-childhood educational outcomes

Maternal body mass index (BMI), but not maternal glucose status, is associated with mid-childhood educational attainment, according to a recent study published in the American Journal of Obstetrics & Gynecology.¹

The short-term consequences of gestational diabetes mellitus (GDM) are often managed through strict control of maternal blood glucose. However, long-term outcomes in children of pregnancies impacted by GDM remain unknown, as high or fluctuating glucose levels may impact offspring neurodevelopment.

Many adverse outcomes have been associated with diabetes during pregnancy.² These include large for gestational age infant, lasting greater offspring adiposity, and other cardiometabolic health outcomes. It has also been theorized that child neurocognitive development is impacted by altered brain structure caused by in-utero exposure to a metabolic milieu.

If maternal GDM impacts child neurodevelopment, then this knowledge can be used to provide early learning interventions that maximize child neurodevelopment potential.¹ However, the association between GDM and child educational attainment may be impacted by cofounding factors such as maternal BMI.

To evaluate the independent effects of GDM and maternal BMI during pregnancy on mid-childhood educational attainment, investigators conducted a prospective UK birth cohort study. Participants included nulliparous women with singleton pregnancies from January 2008 to July 2012 at Rosie Hospital, Cambridge, United Kingdom.¹

BMI was measured using maternal height and weight. Additional data collected included antenatal, delivery, and neonatal outcome data. GDM was determined based on random plasma glucose levels between 11- and 14-weeks’ gestation.

A 75-g oral glucose tolerance test (OGTT) was offered to women with random plasma glucose over 7.0 mmol/L. When clinically indicated, additional OGTTs were performed later in pregnancy.

Data from the National Pupil Database was assessed to determine mid-childhood educational outcomes a 5, 6, and 7 years. A binary outcome determined whether expected educational standards were met at 5 and 6 years based on standardized student assessments. Similar outcomes were generated at age 7 years for reading, writing, science, and mathematics domains.¹

Maternal GDM and maternal BMI were the primary exposures of the study. Patients were stratified into the following categories: BMI under 25 kg/m2 and normoglycemia, BMI under 25 kg/m2 and GDM, BMI of at least 25 mg/m2 and normoglycemia, and BMI of at least 25 mg/m2 and GDM.

Covariates included maternal age, smoking during pregnancy, maternal ethnicity, partner status, maternal occupation, infant sex, gestational age at birth, season of birth, index of multiple deprivation, school funding type, school year at assessment, and serious childhood morbidity.

There were 3249 participants included in the final analysis. GDM exposure during intrauterine development was reported in 4.6% of participants. These patients were often older, and those with a BMI under 25 kg/m2 were less likely to smoke regardless of GDM status.¹

Expected educational standards were met by 79% of the cohort at age 5 and 88% at age 6. At age 7, standards for reading were met by 83%, writing by 77%, science by 90%, and mathematics by 83%.

No differences were observed in the rate of children meeting expected mid-childhood educational standards based on GDM status. These results remained similar during the sensitivity analysis.¹

Plasma glucose levels at 11 to 14 weeks’ gestation were also not associated with the odds of meeting expected educational standards. Similarly, educational attainment at 5 to 7 years was not impacted by the results of a 50-g glucose challenge test taken by mothers at 24 to 28 weeks’ gestation.

Fetal accelerated abdominal circumference growth velocity was also not linked to educational attainment. However, the risks of not meeting expected educational standards at age 5 and 6 years were increased among children of mothers with a BMI of at least 25 kg/m2, with adjusted odds ratios (aORs) of 1.44 and 1.61, respectively.¹

When aged 7 years, children of mothers with a BMI of at least 25 kg/m2 less often met the standards of all domains for educational attainment than those of mothers with a BMI below 25 kg/m2, with aORs of 1.64 for reading, 1.63 for writing, 1.65 for science, and 1.41 for mathematics. The strength of associations grew as maternal BMI increased.

These results indicated no association between maternal GDM and educational attainment, but a direct correlation between increased maternal BMI and the risk of not meeting expected educational standards in mid-childhood. Investigators concluded these findings are relevant for the management of mothers with high BMI.¹

Reference

1. Olga L, Sovio U, Wong H, et al. Maternal high body mass index, but not gestational diabetes, is associated with poorer educational attainment in mid-childhood. Am J Obstet Gynecol. 2024;231:120.e1-9. doi:10.1016/j.ajog.2023.11.1227
2. Fraser A, Lawlor DA. Long-term health outcomes in offspring born to women with diabetes in pregnancy. Curr Diab Rep. 2014;14(5):489. doi:10.1007/s11892-014-0489-x