The Relationship Between HbA1c Levels in the First Trimester of Pregnant Women and Pregnancy Outcomes

Abstract

This study was a retrospective analytical study with the primary objective of examining the association between first-trimester hemoglobin A1c (HbA1c) levels in pregnant women and pregnancy outcomes. The study population consisted of singleton pregnancies, aged 18-45 years, who attended their first antenatal visit at Phaholpolpayuhasena Hospital, Kanchanaburi Province, between October 1, 2022 and September 30, 2024. Eligible participants were those who had their HbA1c measured during the first trimester yielding a total of 366 cases. The research instrument was a data extraction form developed by the investigators to collect retrospective information from medical records. The form comprised maternal demographic and clinical data, first-trimester HbA1c levels, and pregnancy outcomes. The results revealed that first-trimester HbA1c levels were significantly associated with the risk of gestational diabetes mellitus (GDM) (p < .05). Each 1% increase in HbA1c was associated with a 2.6- fold increase in the risk of developing GDM. An HbA1c cutoff of 5.7% yielded the highest discriminatory performance, with an overall accuracy of 73.5%. Furthermore, incorporating additional risk factors maternal age, BMI, family history of diabetes, and gravidity together with HbA1c substantially improved predictive performance, achieving an overall accuracy of 95.0%. In conclusion, first-trimester HbA1c measurement can serve as an early indicator of the risk for adverse pregnancy outcomes. Early identification of high-risk pregnancies through HbA1c assessment, combined with maternal risk factors, may facilitate timely monitoring and appropriate management to reduce complications for both mother and child.