14th September 2024

Gestational diabetes

Pregnancy is a state of increased insulin resistance. Women with additional risk factors for insulin resistance—such as a BMI above 30, Afro-Caribbean or South Asian ethnicity, a first-degree relative with diabetes, or a history of previous macrosomia—are at an increased risk of developing gestational diabetes. Unlike type 1 or type 2 diabetes, gestational diabetes is only present during pregnancy. However, there is a slightly increased risk of developing type 2 diabetes post-pregnancy.

Women with the aforementioned risk factors will undergo an oral glucose tolerance test between 24 and 28 weeks of gestation. A diagnosis is made if their glucose level is above 7.8 mmol/L. Post-pregnancy, a fasting glucose level test is performed for the mother between 6 and 13 weeks to check for the development of Type 2 diabetes.

The risks associated with gestational diabetes include foetal macrosomia (resulting in potential shoulder dystocia), increased likelihood of C-section and induction of labour, stillbirth, preterm labour, neonatal hypoglycaemia, and a slightly increased risk of the baby developing diabetes later in life. Due to these risks, mothers with gestational diabetes (as well as those with Type 1 or Type 2 diabetes during pregnancy, which pose even greater risks to the foetus) will have more frequent ultrasounds to monitor foetal size and amniotic fluid volume.

Treatment for gestational diabetes may involve diet and exercise. If these measures do not achieve target blood sugar levels, metformin or insulin may be used (with insulin reserved for uncontrolled blood sugars). Other medications are not licensed for this condition.

References

• National Institute for Health and Care Excellence (NICE). Diabetes in pregnancy: management from preconception to the postnatal period. Nice.org.uk. 2015
• Durnwald, C. (2023) Gestational diabetes mellitus: Screening, diagnosis, and prevention, UpToDate. Edited by D.M. Nathan, E.F. Werner, and V.A. Barss. Available at: https://www.uptodate.com/contents/gestational-diabetes-mellitus-screening-diagnosis-and-prevention?search=gestational+diabetes&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2 (Accessed: 20 February 2024)