Early Pregnancy Hemoglobin A1C and Pregnancy Outcomes: A Population-Based Study

Abstract

Objective Women with prediabetes are identified from screening for overt diabetes in early pregnancy, but the clinical significance of prediabetes in pregnancy is unclear. We examined whether prediabetes in early pregnancy was associated with risks of adverse outcomes.

Study Design We conducted a retrospective cohort study of pregnant women enrolled in Kaiser Permanente Washington from 2011 to 2014. Early pregnancy hemoglobin A1C (A1C) values, covariates, and outcomes were ascertained from electronic medical records and state birth certificates. Women with prediabetes (A1C of 5.7–6.4%) were compared with those with normal A1C levels (<5.7%) for risk of gestational diabetes mellitus (GDM) and other outcomes including preeclampsia, primary cesarean delivery, induction of labor, large/small for gestational age, preterm birth, and macrosomia. We used modified Poisson's regression to calculate adjusted relative risks (RRs) and 95% confidence intervals (CIs).

Results Of 7,020 women, 239 (3.4%) had prediabetes. GDM developed in 48% of prediabetic women compared with 11% of women with normal A1C levels (adjusted RR: 2.8, 95% CI: 2.4–3.3). Prediabetes was not associated with all other adverse maternal and neonatal outcomes.

Conclusion Prediabetes in early pregnancy is a risk factor for GDM. Future research is needed to elucidate whether early intervention may reduce this risk.

Keywords

prediabetes - gestational diabetes mellitus - A1C - pregnancy - gestational weight gain

Authors' Contributions

L.C. designed the study, conducted statistical analysis, and wrote the article. G.P., O.Y., S.M.S., S.S.O., P.D.W., D.M., S.W., K.M.N., and S.F. made substantial contributions to the conception or design of the study. S.F. made substantial contributions to the acquisition of the data. S.D. obtained funding, designed the study, oversaw the data collection, and supervised the study execution. All authors reviewed and revised the article and approved its final form. L.C. is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and accuracy of the data analysis.

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