Objective To describe the maternal and neonatal outcomes of pregnant women with fasting blood glucose <4.7 mmol/L for whom the diagnosis and treatment pathways differed due to COVID-19. Design, setting and population. An Australian population-based data linkage study involving 3891 women. Methods: Pregnant women with fasting blood glucose <4.7 mmol/L between 24-32 weeks of gestation were categorized into three groups: women diagnosed with gestational diabetes by postprandial hyperglycaemia (PPGDM; n= 226); normal glucose tolerance group (NGT; n= 3125) and women not tested for postprandial hyperglycaemia, mostly during COVID-19 (LFBG; n= 540). The maternal and neonatal outcomes between groups were compared using generalized linear models. Main outcome measures: Risk of Large for gestational age baby. Results: Mean difference in birth weight (-115 grams, 95%CI -175.5— -32.6) and z-scores (-0.11, 95%CI -0.26— 0.02) were lower in the PPGDM group compared to the LFBG group. However, there were no differences between PPGDM and LFBG groups in the risk of large for gestational age (LGA) infants (RR: 1.09, 95%CI 0.66— 1.78). The maternal and neonatal outcomes in the LFBG group were comparable to the NGT group. Conclusion: The risk of LGA was similar across all groups regardless of post prandial glycemia and its treatment. Overall, women with a fasting blood glucose <4.7 mmol/L can be considered as a low-risk group for adverse perinatal outcomes.