Early pregnancy HbA1c pinpoints women at risk of birthing LGA infants

26 Jun 2021
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.

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