Early pregnancy HbA1c pinpoints women at risk of birthing LGA infants

For pregnant women, having HbA1c levels ≥5.6 percent early in pregnancy is linked to a heightened risk of having a large-for-gestational-age (LGA) newborn, according to a study.

The study was conducted in healthcare sites in rural and remote Australia and included 466 women without diabetes aged ≥16 years at first antenatal presentation. HbA1c was evaluated at <20 gestational weeks.

Of the 396 (129 Aboriginal) women who underwent routine 75-g oral glucose tolerance test (OGTT) and achieved a definitive result, 28.8 percent (24.0 percent Aboriginal) had gestational diabetes mellitus (GDM).

Additional risk factors for hyperglycaemia in pregnancy were more prevalent in Aboriginal than non-Aboriginal women. Despite this, Aboriginal women were less likely to complete a routine OGTT (74.8 percent vs 93.7 percent; p<0.001), with less than half completing testing within the recommended timeframe (47.4 percent vs 85.9 percent; p<0.001).

HbA1c ≥5.6 percent (≥38 mmol/mol) was associated with an increased risk of LGA newborn in the total cohort (relative risk [RR], 2.04, 95 percent confidence interval [CI], 1.03–4.01; p=0.040), in addition to having a good predictive ability for GDM among Aboriginal women (71.4 percent, 95 percent confidence interval [CI], 47.8–88.7).

Finally, although significantly more Aboriginal women had elevated HbA1c than non-Aboriginal women (16.3 percent vs 5.2 percent; p<0.001), the former were less likely to develop hyperglycaemia during pregnancy (12.4 percent vs 29.6 percent; p<0.001).

The findings indicate that universal HbA1c measurement at first antenatal presentation may facilitate earlier management of hyperglycaemia and improve perinatal outcome among pregnant women.