High gestational blood glucose ups risk of preterm birth, macrosomia

A higher level of gestational glycated haemoglobin A1c (HbA1c) within the normal range is associated with preterm birth, macrosomia and large for gestational age (LGA), suggests a recent study, adding that interventions aimed at reducing HbA1c may help prevent adverse birth outcomes.

The investigators abstracted data from the Information System of Guangdong Women and Children Hospital in China from September 2014 to March 2018 to examine the relationship between HbA1c within the normal range and the risk of adverse birth outcomes, namely preterm birth, macrosomia and LGA. In total, 5,658 pregnant women with normal gestational HbA1c met the inclusion criteria.

Of the participants, 261 (4.6 percent) had preterm birth, 200 (3.5 percent) had macrosomia, and 325 (5.7 percent) had LGA. On multivariable logistic regression model, each 1-percent increase in maternal HbA1c positively correlated with a higher risk of preterm birth (odds ratio [OR], 1.58, 95 percent confidence interval [CI], 1.08–2.31), macrosomia (OR, 1.70, 95 percent CI, 1.10–2.64) and LGA (OR, 1.38, 95 percent CI, 0.98–1.96).

Of note, the association between gestational HbA1c and preterm birth was seen more often among women with prepregnancy body mass index ≤24 kg/m².

“Higher blood glucose level during gestational periods has been consistently associated with increased risk of adverse birth outcomes,” the investigators said. “Evidence regarding the association between higher HbA1c within the normal range and adverse birth outcomes is limited.”