Gestational diabetes mellitus

This is a pregnancy-induced condition that is characterized by high blood sugar level. This is usually diagnosed from an oral glucose tolerance test at 28 weeks gestation. For this test, you need to fast overnight from 10 pm. There is a 75 g of sugar drink to be taken orally in the morning, with blood taken before taking this drink and 1 and 2 hours after the drink. If the fasting blood glucose is 5.1 or more, 1st hour post-drink is 10.0 mmol/l or more, and 2nd hour post-drink is 8.5 mmol/l or more, you have gestational diabetes mellitus.

Gestational diabetes mellitus, especially if not well controlled, increases the risks of:

• macrosomia or big baby

• shoulder dystocia (difficulties with delivery of the shoulder during labour) which may lead to birth injuries of the baby

• Caesarean section and

• stillbirth, especially if the sugar level is not well controlled

Treatment includes:

1. Dietary modification with restriction of calories and carbohydrates.

2. Regular physical exercise

3. Need for home blood sugar monitoring. This can be accomplished by either:

a) continuous glucose monitoring (CGM) where the aim is to keep the maternal sugar level between 3.9 to 7.8 mmol/l, and the peaks after meals should be between 6.0 to 7.8 mmol/l, or

b) blood sugar profile (BSP) with intermittent pricks of the finger to do hypocount readings of at least 7 times in 1 week.

4. If BSP pre-meals persistently >= 5.3 mmol/l (95 mg/dl), 1st hour post-meals persistently >=7.8 mmol/l (140 mg/dl) and 2nd hour post-meals persistently >= 6.7 mmol/l (best 5.9-6.4 mmol/l or <120 mg/dl), or HbA1c >6.0 - 6.5%. If readings are persistently increased despite dietary interventions, may require oral medications like metformin.

5. If BSP still poor despite metformin, may require insulin injections. This occurs in about 20-30% of patients who were initially started with metformin.

6. Timing of delivery - usually between 38-40 weeks.