Postprandial hyperglycemia screening and pregnancy outcomes: lessons from COVID -19

Aim: To explore whether the diagnosis and treatment of postprandial hyperglycemia in pregnant women with lower fasting glucose improved the maternal and neonatal outcomes compared to the background population.

Methods: A population-based data linkage study involving 3891 women with fasting BG <4.7 mmol/L between 24-32 weeks of gestation who delivered at an Australian tertiary hospital from 2017 to 2021. Women were characterized into three groups:  women diagnosed with gestational diabetes by postprandial hyperglycemia (PPGDM group, n=226), normal glucose tolerance (NGT; n= 3125) group, and low fasting blood glucose (LFBG; n=540) group not tested for postprandial hyperglycemia, mostly during COVID-19, as per the revised GDM diagnostic guidelines during COVID-19.  The maternal and neonatal outcomes between groups were compared using Gaussian method for linear regression of continuous variables and binomial regression for categorical variables.

Results:

The mean baby weight and z score were lower in the PPGDM group compared to LFBG group (b-115.8, b-.11). However, there were no significant differences between PPGDM group and LFBG group in the risk of large for gestational age (LGA) babies (RR: .1.09, 95%CI: .66,1.78). There was a fivefold risk of hypoglycemia at birth (RR 5.25, 95%CI: 1.84 to 14.9) and a three-fold risk of hypoglycemia in the postnatal period (RR: 3.67, 95% CI: 1.86 to 7.26) in the PPGDM group compared to LFBG group. Women diagnosed and treated for PPGDM had a 45% higher risk for cesarean section (RR 1.45, 95% CI: 1.16 to 1.8) compared to the LFBG group. The maternal and neonatal outcomes in the LFBG group were mostly comparable to the NGT group than PPGDM group. 

Conclusion: Despite the lower mean birth weight, the treatment and diagnosis of post-prandial hyperglycemia in women with lower fasting glucose did not alter the risk of LGA compared to women who never underwent diagnosis or treatment of postprandial hyperglycemia. There was an increased risk of neonatal hypoglycemia, additional interventions, and monitoring in women who were treated for postprandial hyperglycemia. The two-step screening approach using fasting BG during COVID-19 did not increase the risk of adverse perinatal outcomes but may reduce health expenditure.