High fasting plasma glucose in early pregnancy and increased risk of adverse pregnancy outcomes in Chinese women: the role of gestational age

Abstract

Aims

To identify any cut-off point to define hyperglycemia and optimal gestational time for hyperglycemia screening in early pregnancy.

Methods

A prospective cohort of 19,134 pregnant women was established in Tianjin, China. The primary outcome was a composite of pregnancy-induced hypertension, macrosomia, large for gestational age (LGA), preterm birth, perinatal death and Apgar score at 1 min < 7. Restricted cubic spline (RCS) was performed to test non-linear associations of fasting plasma glucose (FPG) and gestational age at FPG measurement with composite adverse pregnancy outcome (CAPO). Additive interactions were used to test different effects of FPGs on CAPO by gestational age in early pregnancy.

Results

FPG 5.1–6.9 mmol/L before 20 gestational weeks was associated with significantly increased risks of CAPO, macrosomia and LGA (adjusted ORs: 1.18, 95 %CIs: 1.09–1.29; 1.28, 1.15–1.44; 1.27, 1.15–1.41, respectively) with a discernible threshold. The risk associations persisted after excluding women diagnosed with gestational diabetes mellitus (GDM) at 24–28 gestational weeks. More importantly, FPG 5.1–6.9 mmol/L at 9–19 weeks but not before 9 weeks of gestation was associated with increased risk of CAPO, macrosomia and LGA, with significant additive interactions.

Conclusions

Early GDM could be defined as FPG 5.1–6.9 mmol/L at 9–19 gestational weeks among Chinese pregnant women.