By Dr Janice TUNG, Associate Consultant and Associate Professor Tan Thiam Chye, Visiting Consultant, Department of Obstetrics and Gynaecology, KK Women's and Children's Hospital

Gestational diabetes can affect any pregnant woman, and can have an impact on the baby's health. This guide will help you understand and manage this condition.

What is Gestational Diabetes?

what is gestational diabetes

Diabetes (gestational diabetes mellitus, or GDM) can occur in pregnancy when the body does not produce enough insulin to meet the extra needs in pregnancy. As a result, blood sugar levels may rise.

The good news is that the condition often resolves after delivery. For some women, the condition may persist, and long-term follow-up and treatment will be needed.

GDM can be identified via an oral glucose tolerance test (OGTT) and effectively managed in pregnancy. A proactive treatment plan helps ensure a smooth pregnancy and delivery for you, and protects the health of your baby.

Related: All You Need to Know About Gestational Diabetes

How Does It Affect Your Baby?

how does GDM affect baby

Untreated GDM is associated with elevated blood glucose levels that can cause the following issues for you and your baby.

  • Excess growth (macrosomia)

Your baby may be larger (> 4kg) and have extra fat. This makes delivery more challenging as a bigger baby may not be able to pass through the birth canal, which may lead to a Caesarean section for delivery.

  • Premature delivery

GDM may increase your chances of early labour and delivery. In some cases, the doctor may recommend an earlier delivery because the baby is too large.

  • Respiratory distress syndrome

This is a condition that makes breathing difficult. Babies with this syndrome may need help breathing until their lungs mature. This condition should disappear once your baby's lungs get stronger.

  • Low blood sugar

Some babies of mothers with GDM may develop low blood sugar (hypoglycaemia) shortly after birth because their own insulin production is high. Severe episodes of hypoglycaemia may cause the baby to get seizures. However, prompt feedings and sometimes an intravenous glucose solution often returns the baby's blood sugar level to normal.

  • Increased risk of sudden foetal death or stillbirth

  • Type 2 Diabetes later in life

Babies of mothers with GDM have a higher risk of developing obesity and Type 2 diabetes later in life.

Related: Pregnant When You Have Diabetes: A Checklist

Complications That May Affect a GDM Mother

complications for a GDM mother

If you have GDM, these are the risks you may encounter:

  • High blood pressure (also known as pre-eclampsia)

This is a serious complication of pregnancy that causes high blood pressure and can threaten both your's and your baby's life.

  • Future diabetes

Mums who've had GDM before are more likely to develop it again during a future pregnancy. In addition, they're also more likely to develop Type 2 diabetes.

The Symptoms

Most women with GDM don't have noticeable signs or symptoms. You'll be tested for the condition as part of your prenatal care.

Related: Coping With the Unexpected: Pregnancy Complications

Testing For GDM — Oral Glucose Tolerance Test (OGTT)

The Oral Glucose Tolerance Test (OGTT) requires you to drink a glucose solution after a night of fasting, followed by the drawing of blood samples at the onset, at one and two hours later. If any of your results are higher than the following criteria:

  • Fasting glucose level: ≥5.1mmol/L
  • 1-hour post OGTT glucose level: ≥10.0mmol/L
  • 2-hours post OGTT glucose level: ≥8.5mmol/L,
you could be diagnosed with GDM after your doctor has done a holistic assessment of your pregnancy health.

When is the Test Done?

The test is usually offered to all pregnant women between weeks 24 and 28 of pregnancy.

The Risk Factors

GDM risk factors

There are several risk factors that make one more prone to developing GDM. These include:

  • Being 40 and above years of age
  • High BMI (Pre-pregnancy BMI >23kg/m2)
  • Parents or siblings with diabetes
  • A past history of diabetes in pregnancy
  • A past history of big babies (> 4kg)
  • History of unexplained stillbirth or bad obstetric history

Managing GDM

managing GDM

Treating GDM boils down to one thing: controlling your blood glucose levels so that they don't get too high. This can be done by eating well, exercising and if prescribed, taking insulin or other medication. Not every woman with GDM needs insulin or medication.

Related: 4 Steps To Keep Your GDM Under Control

Will GDM Go Away?

GDM often resolves after you deliver your baby. Your doctor will check your blood glucose levels about six weeks after delivery to check if it's in the normal range again. Do make time for this follow-up OGTT as it is key to detecting diabetes early.

If you've been diagnosed with GDM, don't worry. Tap into the experience of the team of health caregivers who will monitor both you and your baby. Take the necessary steps to control GDM as soon as you're diagnosed. Following your doctor's advice, eating healthily and exercising will ensure both you and your baby remain healthy and that this is just a small blip on the radar.

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Read these next:


The New Art and Science of Pregnancy and Childbirth 2008, World Scientific

Healthy Start for your Pregnancy 2012, Health Promotion Board Singapore

Learn more at and embark on a happy, healthy and active pregnancy.