All about gestational diabetes

GESTATIONAL diabetes refers to high blood sugar (hyperglycaemia) that is first diagnosed in pregnancy. During pregnancy, the placenta produces hormones such as human placental lactogen, oestrogen and cortisol, which can result in insulin resistance. This refers to the inability of the cells in the body to utilise insulin, effectively resulting in a build up of glucose in the blood instead of being taken up into the cells to be used for energy. It is most commonly diagnosed in the third trimester of pregnancy (24- 28 weeks) but can develop at any time during pregnancy.

Who is at risk?

•Older age (women older than 35 years)

•Obesity

•Family history of diabetes

•Gestational diabetes in a previous pregnancy

•Ethnicity (African).

What are the symptoms?

Some women may be asymptomatic and are diagnosed after routine screening and diagnostic tests are done. However, some patients may have increased thirst, increased appetite, and increased urination especially at night.

How is gestational diabetes diagnosed?

Screening tests are done to identify persons at high risk for developing the disease. Patients who are high risk (have one or more risk factors for developing gestational diabetes) are screened during the first trimester of pregnancy (eight to 13 weeks). Low-risk women are screened routinely between 24 to 28 weeks of pregnancy.

The screening test done is called the O’Sullivan’s Test. This involves the patient drinking a 50g glucose solution after which a blood test is done one hour later to check her blood sugar. Patients with an abnormal O’Sullivan’s Test are asked to do a diagnostic test called an Oral Glucose Tolerance Test. This involves doing a fasting blood sugar after which the patient is given a 75g glucose drink followed by one hour and two hours blood sugar tests.

What are the complications?

Gestational diabetes can result in complications for the pregnant woman as well as the baby during pregnancy and birth. It is therefore important for gestational diabetes to be well controlled.

Maternal complications

• High blood pressure or pre-eclampsia, a more serious complication of high blood pressure

• Birth trauma

• Increased need for caesarean delivery

• Development of type II diabetes mellitus.

Foetal complications

• Foetal macrosomia — large baby

• Difficult delivery — for example, shoulder dystocia in which the infant can become wedged in the birth canal

• Need for caesarean section

• Pre-term birth

• Breathing difficulties

• Hypoglycaemia — low blood sugar after birth

• Stillbirth — foetal death during or shortly after delivery.

How is gestational diabetes managed?

It is important that steps are taken help prevent gestational diabetes. Primary prevention is key. Women are encouraged to visit their ObGyn prior to becoming pregnant for pre-conception counselling. Women at high risk of developing gestational diabetes are optimised for pregnancy. They are encouraged to have a balanced diet consisting of foods from all major food groups, including complex carbohydrates, proteins, nuts, and vegetables. Increased physical activity is encouraged in an attempt to achieve an ideal body weight.

Once diagnosed with gestational diabetes, the aim is for tight glucose control in an attempt to decrease complications to mother as well as baby. Patients are taught to monitor blood sugar levels using a special machine called a GMR machine. Blood sugar measurements are done four times daily; fasting two hours after breakfast, lunch and dinner.

Patients are placed on special diabetic diets. If blood sugar is not controlled on diet alone, then patients are started on oral hypoglycaemic agents or a medication called insulin. There is close monitoring of mother and foetus, hence patients are usually seen more frequently than the routine number of antenatal visits. Foetal growth and development are frequently assessed and the mother’s blood sugar is tightly controlled.

Delivery

Vaginal delivery is the preferred route of delivery unless there are contraindications. The timing of delivery will be dependent on certain factors, for example level of blood glucose control. Patients often have a scheduled delivery based on the guidance of their obstetricians.

After delivery, blood sugar generally returns to normal levels, therefore most patients do not require anti-diabetic drugs. However a 75g, two hour oral glucose tolerance test is done six to 12 weeks after delivery using non-pregnant criteria.

Dr Carla Nicholson-Daley is an Obstetrician and Gynaecologist practising at Gynae Associates, 23 Tangerine Place. She can be reached at 876-929-5038, 876-669-2851 or by e-mail at drcnicholsondaley@gmail.com.