Background The midpregnancy normal-range HbA1c value and adverse birth outcomes were controversial. To address this lack of data, we examined the associations between midpregnancy normal-range HbA1c value and adverse birth outcomes. Objective To evaluate whether an association exists between the midpregnancy normal-range HbA1c value and adverse birth outcomes. Materials and Methods A total of 8389 women in their midpregnancy with normal gestational HbA1c value from the Affiliated Hospital of Jining Medical University in China participated in this study from January to December 2019. Subjects were stratified on the basis of their midpregnancy HbA1c value, and multivariate logistic regression was implemented to investigate the association between different HbA1c values and adverse birth outcomes. Results Incidence of preterm birth, macrosomia, and large for gestational age (LGA) for 8389 subjects were 4.8%, 6.3% and 16.5%, respectively. The multivariate logistic regression model demonstrated that the risk of preterm birth (adjusted odds ratio [OR]: 1.71 and 95% confidence interval [CI]: 1.25–2.34), macrosomia (OR: 1.68 and 95% CI: 1.26–2.22), and LGA (OR: 1.53 and 95% CI: 1.28–1.83) increase for every increase of 1% maternal HbA1c. Women with a prepregnancy body mass index (BMI) of < 25 kg/m 2 have a stronger correlation with HbA1c values and adverse birth outcomes than women with a prepregnancy BMI of ≥25 kg/m 2 . Conclusion Our results indicated that the midpregnancy normal-range HbA1c level within the normal range is associated with adverse birth outcomes. Monitoring and controlling HbA1c may reduce the risk of adverse birth outcomes.

Background: Previous studies have examined the association between glycated hemoglobin (HbA1c) and hemoglobin (Hb) levels among non-diabetic people. However, there are no reports relating to the correlation between HbA1c values and anemia in women without gestational diabetes. We, therefore, examined whether there is an association between mid-pregnancy HbA1c values and anemia in women without gestational diabetes. Methods: This retrospective cohort study was conducted at the Affiliated Hospital of Jining Medical University, Jining, China, from January to December 2019. Cases of single pregnancies in women above 18 years old, with recorded HbA1c values at 14-27+6 weeks of gestation, were examined. Women with pregestational diabetes mellitus (GDM) or the development of GDM were excluded. The association between variations in mid-pregnancy HbA1c values and anemia was examined. Results: Among 8553 women without gestational diabetes, univariate analysis results demonstrated a significant positive relationship between (P<.001) mid-pregnancy HbA1c values and anemia, after adjusting for confounding factors. Multivariate piecewise linear regression showed that anemia decreased when HbA1c values were <4.6% (OR 0.40; 95% CI, 0.15-1.04; P=.592) and increased when HbA1c values were was >4.6 % (OR 3.83; 95% CI, 2.95-4.98; P<.0001). Conclusion: This study showed a nonlinear relationship between mid-pregnancy HbA1c values and anemia in women without gestational diabetes. When the HbA1c values increased to the inflection point, they were positively correlated with anemia. Further studies are needed to explore this relationship and the mechanisms involved in the future.