The effect of treatment targets on perinatal outcomes in pregnancies affected by gestational diabetes; a multi-centre retrospective cohort study.

Abstract

Background: Gestational diabetes (GDM) is a significant and increasing diagnosis globally, and in Australia complicates approximately 18% of pregnancies. GDM may lead to babies being born large for gestational age (LGA), and other complications. There is currently no consensus on optimal blood glucose treatment targets. This study aims to determine pregnancy outcomes in patients with GDM when treated according to tighter or less tight blood glucose targets. Method(s): This was a retrospective cohort study. We included data from the major metropolitan hospitals in Victoria, Australia between January 2020 and December 2022. Women with a diagnosis of GDM were included. Multiple births and births prior to 37 weeks were excluded. The hospitals were grouped according to fasting BGL targets: <<tighter>> (<=5.1 mmol/L) or <<less tight>> (<=5.5-5.6 mmol/L). Clinical care was according to local protocols. The primary outcome was LGA, and we compared other maternal and infant outcomes. Result(s): There were 25,041 births included, 12,423 (49.6%) in the <<tighter>> group, and 12,618 (50.4%) in the <<less tight>> group. After adjusting for delivery hospital and maternal demographics, there was no difference in the primary outcome of LGA (10.4% in tighter target vs 9.5% in less tight target (p=0.85)). There was no difference in secondary outcomes. More women were treated with insulin in the tighter target group (53%) compared with 35% in the less tight group (p<=0.001). Conclusion(s): Tighter blood glucose targets were not associated with improved outcomes for women or infants, but were associated with an increase in insulin use.