Gestational diabetes

What is it?

Gestational diabetes is diabetes that develops during pregnancy in a woman who did not already have diabetes (CDC). It is high blood sugar that can occur at any stage but is more common in the second or third trimester, and it usually goes away after birth (NHS).

It is common in our region: IDF estimates 14.1% of pregnancies in the Middle East and North Africa in 2021 (women aged 20–49), and says 1 in 7 live births in the region was affected by high blood sugar in pregnancy. In the United States it affects 5% to 9% of pregnancies each year (CDC). We found no figures for each Gulf country.

It is different from type 1 and type 2 diabetes, which may already be present before pregnancy.

Causes

Pregnancy hormones and weight gain cause insulin resistance, and all pregnant women have some insulin resistance late in pregnancy; gestational diabetes happens when the body cannot make enough extra insulin (NIDDK).

It usually develops around the 24th week of pregnancy (MedlinePlus).

Risk factors

• Being over 40 (NHS).
• A BMI above 30 or being overweight (NHS and CDC), or gaining too much weight during pregnancy (NIDDK).
• A previous baby weighing 4.5kg (10lb) or more (NHS), or over 9 pounds according to the CDC.
• Gestational diabetes in a previous pregnancy (NHS and CDC).
• A parent or sibling with diabetes (NHS).
• South Asian, Black, African-Caribbean or Middle Eastern origin (NHS).
• Gastric bypass or other weight-loss surgery (NHS).
• Polycystic ovary syndrome (CDC).

The NHS offers a glucose tolerance test to anyone with one or more risk factors.

Symptoms

It usually causes no symptoms; if there are any, they are mild, such as increased thirst or passing urine more often. Testing is the only way to know (CDC).

Symptoms of high blood sugar can also include a dry mouth, tiredness, blurred eyesight and genital itching; many are common in pregnancy anyway, so discuss them with your midwife or doctor (NHS).

How is it diagnosed?

Testing is usually done between weeks 24 and 28, earlier for women at higher risk (CDC and NIDDK).

• Glucose challenge test: no fasting; you drink a sugary liquid and blood is drawn after an hour; a high result leads to a glucose tolerance test (NIDDK).
• Oral glucose tolerance test: fast for 8 to 10 hours (water is usually allowed), give a blood sample, drink the glucose drink, then a second sample after 2 hours (NHS); in the U.S. version, blood is drawn every hour for 2 to 3 hours, and abnormal values at two or more points mean gestational diabetes (NIDDK).

If you had gestational diabetes before, the test is offered soon after the booking visit and again at 24–28 weeks if the first is normal (NHS).

• Oral glucose tolerance testLab test
• Fasting plasma glucoseLab test

Treatment

Treatment starts with a healthy eating plan made with your care team, regular physical activity and checking blood sugar at home (CDC and NIDDK).

• Food: regular meals without skipping, low glycaemic index starchy foods, swapping sugary snacks for fruit and nuts, and sugar-free drinks (NHS).
• Activity: at least 150 minutes of moderate activity a week plus strength exercises on 2 or more days (NHS), or 30 minutes on 5 days of the week (NIDDK).
• Blood sugar checks: usually before breakfast and 1 hour after each meal, against personal targets set by your team (NHS).
• Medicine: if blood sugar is not controlled 1 to 2 weeks after changing food and activity, or is very high at diagnosis, metformin or insulin is usually prescribed, occasionally glibenclamide (NHS). Insulin does not harm the baby and is usually the first choice according to NIDDK.
• Monitoring the baby: extra scans at 28, 32 and 36 weeks and regular checks from week 38 (NHS).

Giving birth in hospital is advised, ideally around weeks 38 to 40; induction or a caesarean is usually offered if the baby has not been born by 40 weeks and 6 days (NHS).

Treatments are named here as commonly used options, not as a prescription. The doctor decides the plan and the dose for each person; do not change any medicine without a professional.

Complications

Most pregnancies with gestational diabetes are otherwise normal with healthy babies (NHS), but it can cause:

For the baby

• A larger baby, a harder birth and more need for induction or caesarean, premature birth, low blood sugar or jaundice after birth, and rarely stillbirth (NHS).
• Breathing problems and, later in life, overweight and type 2 diabetes (NIDDK).

For the mother

• Pre-eclampsia, a higher chance of caesarean birth, type 2 diabetes later in life (NIDDK), and too much amniotic fluid (NHS).

Follow-up

After birth, the baby is fed within 30 minutes and then every 2 to 3 hours until its blood sugar is stable, and its blood sugar is tested. The mother's diabetes medicines are usually stopped after birth (NHS).

A diabetes test is needed after birth and regularly afterwards; sources differ on timing:

• NHS: 6 to 13 weeks after birth, then yearly if normal.
• CDC: 4 to 12 weeks after birth, then every 1 to 3 years.
• NIDDK: no later than 12 weeks after birth, then every 3 years.

About half of women who had gestational diabetes go on to develop type 2 diabetes (CDC), and it can come back in a later pregnancy (NHS), so get checked for diabetes before planning another pregnancy (NHS).

Prevention

Before pregnancy, losing extra weight and being more active may lower the chance of gestational diabetes. Don't try to lose weight during pregnancy, but gaining too much too quickly raises the risk; ask your doctor what gain is right (NIDDK).

After gestational diabetes: losing 5% of your weight if overweight, about 150 minutes of activity a week and healthy eating lower the risk of type 2 diabetes (CDC), and breastfeeding helps too (NIDDK).

Living with it

Ramadan fasting: Tommy's (a UK charity) says not fasting matters most for women with complications such as gestational diabetes, because fasting makes blood sugar hard to keep stable; consult your doctor before any decision, and religious scholars for the ruling.

Common questions