Predictors for adverse pregnancy outcomes in women with pre-gestational diabetes: a retrospective study

Abstract

Objective: To identify predictors for adverse pregnancy outcomes among women with pre-gestational diabetes.
Methods: We retrospectively reviewed medical records of women with pre-gestational diabetes who attended the Tuen Mun Hospital between 1 January 2012 and 30 December 2022 for antenatal care and delivery. Composite adverse early perinatal outcomes included spontaneous fetal loss before 24 weeks and congenital malformations. Composite adverse maternal outcomes included pre-eclampsia and Caesarean section. Composite adverse neonatal outcomes included preterm delivery <37 weeks, small and large for gestational age, shoulder dystocia, hypoglycaemia, Apgar score <7 at 5 minutes, arterial cord blood pH <7.0, admission to a neonatal intensive care unit, stillbirth, and death within 28 days of life. Factors associated with adverse pregnancy outcomes were identified.
Results: Among 245 women included in analysis, there were 10 spontaneous pregnancy losses before 24 weeks, four stillbirths, and 41 congenital malformations, which resulted in four terminations of pregnancy. The glycated haemoglobin (HbA1c) level at the first antenatal visit was a predictor for composite adverse early perinatal outcomes (adjusted odds ratio [aOR]=1.27, p=0.013). The rate of congenital anomaly increased threefold from 10% when the HbA1c level was <5.6% to 37.1% when the HbA1c level was >9.1% (p=0.003). Predictors for composite adverse maternal outcomes were a pre-pregnancy body mass index ≥25 kg/m2 (aOR=2.04, p=0.033) and chronic hypertension (aOR=3.59, p=0.009), whereas the predictor for composite adverse neonatal outcomes were the HbA1c level before delivery (aOR=1.57, p=0.025). Pre-pregnancy medical care was associated with a lower maternal HbA1c level at the first antenatal visit (6.8% vs 8.2%, p=0.002) and earlier gestational age at the first antenatal visit (8 vs 12 weeks, p<0.001), compared with no pre-pregnancy medical care.
Conclusion: Maternal glycaemic control and body mass index are the major modifiable risk factors for adverse pregnancy outcomes in women with pre-gestational diabetes. Pre-pregnancy medical care should emphasise lowering the HbA1c level and bodyweight at early pregnancy to avoid adverse pregnancy outcomes.