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Continuous glucose monitoring in pregnancy improves neonatal outcomes

By Bianca Nogrady
Continuous glucose monitoring (CGM) during pregnancy in women with type 1 diabetes could significantly improve neonatal health outcomes, a new study has found. 

Writing in The Lancet, researchers reported the results of an international, open-label randomised controlled trial of CGM plus capillary glucose monitoring (CGM group), or capillary glucose monitoring alone (control group), in 325 women with type 1 diabetes; 215 of whom were pregnant and 110 planning a pregnancy.

They found a 49% reduction in the incidence of large for gestational age neonates, a 52% reduction in neonatal intensive care admissions lasting longer than 24 hours, a 55% reduction in neonatal hypoglycaemia, and one day shorter hospital stays in the pregnant CGM users compared with controls.

However, the number of women planning pregnancy who conceived – 34 – was too small to enable analysis in this group. 

The pregnant women using CGM spent more time with glucose levels in target (68% vs 61%), and there was a small but significant mean improvement in HbA1c of -0.19% from baseline to 34 weeks’ gestation in the CGM group.

This group also spent less time hyperglycaemic (27% vs 32%) but had a similar number of severe hypoglycaemic episodes and amount of time spent hypoglycaemic.

‘The improvement in glucose control was achieved without increased maternal hypoglycaemia, gestational weight gain or total daily insulin dose, but with an increase in the rate of change in glucose concentrations,’ the authors wrote. 

The women in the CGM group had a higher rate of the adverse events normally associated with CGM, particularly skin reactions. 

Commenting on the paper, endocrinologist and obstetric physician Dr Helen Barrett from the University of Queensland Centre for Clinical Research in Brisbane said it was an exciting and promising study addressing the often-challenging situation of managing type 1 diabetes in pregnancy. 

‘The promising thing about it is that there was a small difference in the change in HbA1c between enrolment and 36 weeks which was the primary outcome measure,’ Dr Barrett told Endocrinology Today.

‘This is a high risk population where we now have a large randomised study showing there’s clinical benefit from continuous glucose monitoring and I think it certainly leads us towards having serious discussions about making it readily available to this group,’ she said.

However, Dr Barrett pointed out that the CGM group had a higher rate of medical visits than the control group, many of which were related to the monitoring, which means the expected forthcoming cost–benefit analysis of this study will be important.
Lancet 2017; doi: 10.1016/S0140-6736(17)32400-5.