Gestational Diabetes

Dr. LAM Sze Wing, Helena

Honorary Consultant in Obstetrics & Gynaecology

Specialist in Obstetrics and Gynaecology

Gestational diabetes is characterised by high blood glucose levels in pregnant women with no prior history of diabetes. During pregnancy, the effect of insulin deceases as the placenta releases certain insulin-resisting hormones.

Most, not all women can produce adequate insulin to maintain normal blood glucose levels during pregnancy. For the minority, the situation will worsen in the late stage of pregnancy and lead to gestational diabetes.

High-Risk Group

• Overweight
• Having given birth to babies weighing over 4kg
• With a previous history of premature birth and stillbirth
• With a previous history of gestational diabetes
• With polycystic ovary syndrome
• Pregnancy at age 35 or above
• Twin pregnancy
• With a family history of diabetes

According to the guidelines of the American Diabetes Association, pregnant women should undergo a 75g Oral Glucose Tolerance Test within 24 to 28 weeks of gestation. Diagnosis is confirmed if any of the following indices exceeds the normal level below:

Diagnostic Criteria for the 75g Oral Glucose Tolerance Test during Pregnancy:

Gestational Diabetes Affects Both Mothers and Babies

Early detection and proper treatment are essential to both mothers and babies. If treated improperly, gestational diabetes may give rise to a host of complications in mothers, such as excess amniotic fluid (polyhydramnios), premature birth, difficult labour, gestational hypertension and edema.

For babies, gestational diabetes is associated with giant babies, stillbirths, neonatal deaths, respiratory distress syndrome, hypoglycemia, infant jaundice and cardiomyopathy.  Vascular sclerosis, hypertension, etc. may also occur after birth. Regular prenatal check-up is of paramount importance.

Consultation with Diabetes Nurses and Dietitians

Women with gestational diabetes can keep normal blood glucose levels with diet control, adequate exercise and self-monitoring. If in doubt, please consult your diabetes nurses and dietitians for guidance. 

Diabetes nurse can teach you how to self-monitor the blood glucose levels and provide a better understanding of your condition. Dietitians can also give you dietary guidance to ensure adequate nutrition for fetal growth while maintaining normal blood glucose levels.  

You may need to be referred to an Endocrinologist for insulin therapy if diet control fails.

Post-pregnancy Tests and Follow-ups Reduce Future Risk of Diabetes

Women with gestational diabetes are far more likely to develop type 2 diabetes after childbirth if the condition is left untreated during pregnancy. A glucose tolerance test is recommended in 6 to 8 weeks after childbirth. While the blood glucose levels will return to normal in most women after childbirth, some may continue to have the same problem and require postnatal care and follow-ups.