Higher haemoglobin levels up GDM risk in pregnant women

A study in Chile has noted the presence of elevated haemoglobin (Hb) among pregnant women despite the increased prevalence of depleted iron stores, contributing to adverse maternal outcomes.

A total of 1,730 pregnant women with Hb or haematocrit (Hct) measured in the first or second trimester were included in this prospective cohort study.

The authors assessed serum ferritin (SF) and soluble transferrin receptor (sTfR) in a random subgroup of 350 second-trimester pregnant women. They also explored the associations between iron biomarkers and maternal and neonatal outcomes using multivariable logistic regression models.

Fifty percent of women in the first trimester and 12 percent in the second trimester had elevated Hb (>13 g/dL). Less than 10 percent had anaemia in the first and second trimester, while 38 percent had depleted iron stores (SF concentration <15 µg/L).

The prevalence rate of gestational diabetes mellitus (GDM) was 17 percent, while that of pre-eclampsia and macrosomia was 3.3 percent and 7.1 percent, respectively.

Women with higher second-trimester Hb (odds ratio [OR], 1.23, 95 percent confidence interval [CI], 1.00‒1.52) and Hct (OR, 1.09, 95 percent CI, 1.01‒1.17) had greater odds of developing GDM. Those with first-trimester anaemia also had a higher likelihood of pre-eclampsia (OR, 5.67, 95 percent CI, 1.20‒27.0). SF and sTfR, on the other hand, showed no significant association with GDM or pre-eclampsia.

“Optimizing maternal iron status during pregnancy requires addressing both deficiency and potential excess,” the authors said.