High night-time blood sugar level associated with large baby in women with gestational diabetes

The aim of this study was to investigate the role of glucose changes in the development of a large baby in women with gestational diabetes. The main finding of the study was that mothers who had large babies had high blood glucose levels at night.

Gestational diabetes mellitus (GDM) is diabetes that occurs during pregnancy. This is where the body does not produce enough insulin (the hormone that controls blood glucose) resulting in high blood glucose levels. Women with GDM are more likely to have babies that are much larger than they should be for their due dates. This is called a large for gestational age (LGA) baby. LGA babies have a higher risk of preterm delivery, still birth and delivery difficulties.

Continuous blood glucose monitoring allows a more accurate look at blood glucose control throughout the day. Large changes in blood glucose levels are called glucose variability (GV). Blood glucose target range is 3.9-7.8 mmol/l. The effect of GV on a developing baby in a mother with GDM is not known.

This study included 153 women with GDM. These women had continuous blood glucose monitoring for 7 days at 30-32 weeks of pregnancy. 14 women (9%) delivered an LGA baby.

The average blood glucose levels of women who delivered an LGA baby (6.2 mmol/l) were significantly higher than the women who did not deliver an LGA baby (5.8 mmol/l). There were no significant differences in the amount of time spent in, above or below the target blood glucose range between the two groups. Mothers who delivered an LGA baby had a significantly higher blood glucose level during the night (6.0 mmol/l) compared to those who did not deliver an LGA baby (5.5 mmol/l).

The authors concluded that mothers of LGA infants have higher blood glucose levels overnight compared to mothers without LGA.

Women were not asked to keep a diary of their diet during the study. Since blood glucose levels are highly influenced by the diet, this might have influenced the results.

If you have concerns about GDM, please discuss with your doctor.