MONDAY, April 22, 2019 (HealthDay News) -- For women with type 1 diabetes (T1D), the risk for preterm birth is strongly associated with periconceptional hemoglobin A1c (HbA1c) level, according to a study published online April 22 in the Annals of Internal Medicine.
Jonas F. Ludvigsson, M.D., Ph.D., from the Karolinska Institutet in Stockholm, and colleagues examined preterm birth risk according to periconceptional HbA1c levels in women with T1D. The population-based cohort study included 2,474 singletons born to women with T1D and 1,165,216 reference infants born to women without diabetes.
The researchers found that preterm birth occurred in 22.3 and 4.7 percent of infants born to mothers with T1D and without diabetes, respectively. For women with a periconception HbA1c level <6.5 percent, the incidence of preterm birth was 13.2 compared with women without T1D. For those with a periconception HbA1c level 6.5 to <7.8 percent, the incidence of preterm birth was 20.6, and the incidence was 28.3 in women with a level 7.8 to <9.1 percent. Incidence was 37.5 percent in those with an HbA1c level ≥9.1 percent. The adjusted risk ratios were 2.83, 4.22, 5.56, and 6.91, respectively. For medically indicated preterm birth, the corresponding adjusted risk ratios were 5.26, 7.42, 11.75, and 17.51, respectively. For spontaneous preterm birth, the corresponding adjusted risk ratios were 1.81, 2.86, 2.88, and 2.80, respectively.
"Preterm birth among women with T1D was strongly linked to periconceptional HbA1c levels, although women whose HbA1c levels were consistent with recommended target values also were at increased risk for preterm birth as well as other adverse pregnancy outcomes," the authors write.
One author disclosed financial ties to the pharmaceutical industry.