It's not unsual for a woman's blood sugar levels to rise during pregnancy due to hormonal changes. However, if the condition persists, it could lead to gestational diabetes mellitus (GDM), harming both mother and baby.

Read on to learn more about gestational diabetes as Prof Tan Kok Hian​​, Head and Senior Consultant of the Perinatal Audit and Epidemiology Unit, Department of Maternal Fetal Medicine, at KK Women’s and Children’s Hospital (KKH), a member of the SingHealth group, answers questions from our readers.​


Question by angie.k (reposted by Forum Admin)

Hi Prof,

I have hyperemesis gravidarum and lost a lot of weight in the first 4 months. I'm now in my sixth month and have gained 9.5kg because I've been eating more (to make up for lost time). My gynae said my weight gain is too fast and to watch my sugar intake (because i've been craving a lot of bubble tea and skittles). The thing is I can't tolerate a lot of foods, even with medication, and the things that i can eat are usually sweet. I dont normally eat sweet things before pregnancy. Do you think i will be at risk of gestational diabetes? I dont have a family history of diabetes.

Answered by Professor Tan Kok Hian, Head and Senior Consultant, Perinatal Audit & Epidemiology Unit, KK Women’s and Children’s Hospital.

Gaining 9.5kg from 4 months to 5 or 6 months is too rapid. The total weight gain for a pregnant woman with normal BMI (body mass index) before delivery should be between 11kg and 16kg overall for the whole pregnancy. During the first trimester, a pregnant woman should be putting on between 500g and 2kg. For the rest of the pregnancy, she should be putting about 300g to 500g per week. So it is important to slow your weight gain to prevent overall excessive weight gain during pregnancy which increases your risk for developing GDM.

It is ok to have cravings for sweet foods and beverages but it is important to take it in moderation. The total amount of calories and carbohydrates (sweet or not sweet) has to be moderated, as excessive calorie intake leads to excessive weight gain. On average, a Singaporean woman needs about 1,700 calories a day. The average pregnant woman only requires about an additional 300 calories per day. For more information on maintaining a healthy diet during pregnancy, please click here.


Question by sandra

Dear Dr Tan,

I was told that pregnant women can get diabetes and that there are no signs and symptoms of the condition – is that true? If there are signs, what can I look for? I am 18 weeks pregnant. Can I get myself tested? Whom should I ask? The GP or my gynae? Thank you.

Answered by Professor Tan Kok Hian, Head and Senior Consultant, Perinatal Audit & Epidemiology Unit, KK Women’s and Children’s Hospital.

Typically, pregnant women with gestational diabetes mellitus (GDM) display no symptoms. Their raised blood sugar levels are likely to be discovered during a routine antenatal check-up. However, some pregnant women may experience increased thirst, urination, appetite, and fatigue.

From 1 January 2016, KK Women’s and Children’s Hospital (KKH) and Singapore General Hospital (SGH) have been offering universal GDM screening to all pregnant women at 24 to 28 weeks gestation. Hence, if you are being cared for at KKH or SGH, you should be offered a GDM screening when you are 24 weeks to 28 weeks gestation. If you are receiving antenatal care in other hospitals, please check with your obstetrician during an antenatal check-up.


Question by Eileen

Dear doctor

I am careful with my pregnancy diet as I have been told that I could get diabetes while I am pregnant. Is that enough? Or must I take other foods to prevent the diabetes from happening? Will the diabetes really happen anyway? Thanks!

Answered by Professor Tan Kok Hian, Head and Senior Consultant, Perinatal Audit & Epidemiology Unit, KK Women’s and Children’s Hospital.

Diabetes can happen in pregnancy when the body does not produce adequate amounts of the hormone insulin to deal with sugar control during pregnancy. As a result, the sugar levels in the pregnant woman may rise. In most cases, the condition disappears after delivery. In others, the condition may persist and long-term follow-up and treatment of the diabetes is required. A repeat oral glucose test (OGTT) for diabetes will be performed six weeks after delivery.

It is not clear why some pregnant women develop GDM and others do not. A woman’s risk for developing gestational diabetes increases if she:

  • Is over the age of 35 when she became pregnant
  • Is overweight before she became pregnant
  • Has pre-diabetes before she became pregnant
  • Has a family history of diabetes
  • Has high blood pressure
  • Had a previous pregnancy which led to an unexplained miscarriage or stillbirth; or the birth of a baby who weighed over four kilogrammes

It is good that you are careful with your pregnancy diet. Having a healthy and balanced diet as well as regular exercises help to prevent excessive weight gain which can reduce the risk of GDM. It can also help to improve blood glucose control. This will help to manage the condition and prevent any further complications associated with GDM.


Question by lisa

Hi doctor!

If I get diabetes while I am pregnant, will my baby get it too? And after she is born? Can it be treated and what's the treatment then? Thanks a lot.

Answered by Professor Tan Kok Hian, Head and Senior Consultant, Perinatal Audit & Epidemiology Unit, KK Women’s and Children’s Hospital.

The treatment of GDM varies, depending on the result of the oral glucose tolerance test (OGTT). If the condition is mild, controlling the diet is often enough. For more severe cases, oral medications (metformin) or insulin injections (depending on severity) may be required for the remainder of the pregnancy. A dietitian will advise on a sensible eating plan which is to have a healthy diet and foods with a low glycaemic index. Regular exercise (such as walking for 30 minutes after a meal) to improve glycaemic control is recommended. Women with GDM should have regular fetal growth monitoring and delivered by term gestation.

If GDM is detected early and managed timely and appropriately, the mother and child will usually have a good outcome. Although GDM resolves in most women after their pregnancy, these women still have a much higher risk of developing T2 DM in their lifetime. T2DM, if not detected early or not well-controlled, can be associated with permanent complications to the kidneys, eyes and blood vessels. There is evidence that certain lifestyle changes to diet and exercise can help delay or even prevent the development of T2DM after GDM. Follow-up after delivery is therefore important for detecting persisting or the onset of T2DM, in order to achieve prompt and optimal control and treatment of the condition.

Poorly controlled or untreated gestational diabetes can put the mother and her baby at risk of the following:

Risks of gestational diabetes for the baby:

  • Excessive weight at birth > four kilogrammes (macrosomia)
  • Fetal abnormalities
  • Sudden fetal death
  • Fetal respiratory distress syndrome
  • Low blood sugar or hypoglycemia after birth
  • Jaundice after birth
  • Type 2 diabetes later in life

Risks of gestational diabetes for the mother:

  • High blood pressure/preeclampsia and eclampsia during pregnancy
  • Urinary tract infection
  • Premature delivery
  • Caesarean delivery
  • Gestational diabetes in future pregnancy
  • Type 2 diabetes in future

Question by blueskies (reposted by Forum Admin)

Dear Dr Tan

What can I do while I am pregnant (now 15 weeks) so I don't get gestational diabetes? I already don't have a good appetite tho it's funny – I have a craving for tong shui (sweet soup) and kopi (I drink half a small cup each time). All these I try not to eat or drink more than 3 times a week – is that too much? Thanks.

Answered by Professor Tan Kok Hian, Head and Senior Consultant, Perinatal Audit & Epidemiology Unit, KK Women’s and Children’s Hospital.

Having a healthy and balanced diet as well as regular exercises help to prevent excessive weight gain which can reduce the risk of GDM. It can also help to improve blood glucose control. This will help to manage the condition and prevent any further complications associated with GDM. 

It is natural to have food cravings during pregnancy as the physiology of the mother changes during this period. What is important is to remember the basic principle in life – moderation. So it is fine to have a food you crave for three to four times a week in moderation.  A healthy and balanced diet means first and foremost that the total amount of food consumed is not excessive.


Question by dani (reposted by Forum Admin)

Dear doctor

I work shifts and sometimes it's quite difficult to wind down when I come home. My first trimester was bad – I had severe morning sickness. And I could barely sleep 4 hours at a stretch. My mother tells me that if I do not get enough sleep, I am at risk of diabetes while I'm pregnant. Is that true? This is my second child and I am at 22 weeks. I didn't get diabetes with my first pregnancy. What are the chances that I will with this one?

Answered by Professor Tan Kok Hian, Head and Senior Consultant, Perinatal Audit & Epidemiology Unit, KK Women’s and Children’s Hospital.

The good news is that if you did not have GDM in your first pregnancy, the risk for GDM is lower for your second pregnancy, compared to other pregnant women of the same age. However do note that higher age and increased weight (BMI) since the first pregnancy may increase GDM risks.

In many mothers, morning sickness is usually worse in the second pregnancy compared to the first. However this generally only lasts for the first trimester.
Although the risk of diabetes is not related directly to the amount of sleep, it is recommended to have good quality and sufficient sleep to maintain good health, especially towards the third trimester.


Question by georgina26 (reposted by Forum Admin)

Hi Dr Tan

I've just been diagnosed with GDM and as I usually keep a healthy lifestyle – I swim and do yoga, and I uses to run marathons before I got pregnant – my doctor says it will go away after I give birth. But I forgot to ask him if diabetes could come back at a later stage (years later, not pregnant). Will it? Thank you!

Answered by Professor Tan Kok Hian, Head and Senior Consultant, Perinatal Audit & Epidemiology Unit, KK Women’s and Children’s Hospital.

It is good that you adopt a physically-active lifestyle prior to pregnancy, and you should continue to do so as it will help regulate your blood sugar level. Do seek your obstetrician’s advice on suitable exercises to perform during pregnancy.

In most cases, GDM disappears after delivery. In others, the condition may persist and long-term follow-up and treatment of the diabetes is required. A repeat oral glucose test (OGTT) for diabetes will be performed six weeks after delivery.

There are studies to show that up to 70 per cent of women who have GDM will develop diabetes at some point in their lifetime following delivery.


Question by yeo.sally (reposted by Forum Admin)

Hi doctor

I am planning to start a family. How would I know if I'm at risk of gestational diabetes? There's no history of diabetes in my family but I hear that it can happen anyway. How will that affect my unborn baby? Thanks!

Answered by Professor Tan Kok Hian, Head and Senior Consultant, Perinatal Audit & Epidemiology Unit, KK Women’s and Children’s Hospital.

To enable a good health outcome, it is important to promptly identify GDM so timely intervention can be provided. From 1 January 2016, KK Women's and Children's Hospital (KKH) and Singapore General Hospital (SGH) have been offering universal GDM screening to all pregnant women at 24 to 28 weeks gestation. Hence, if you are being cared for at KKH or SGH, you should be offered a GDM screening when you are 24 weeks to 28 weeks gestation. If you are receiving antenatal care in other hospitals, please check with your obstetrician during an antenatal check-up.

Diabetes can happen in pregnancy when the body does not produce adequate amounts of the hormone insulin to deal with sugar control during pregnancy. As a result, the sugar levels in the pregnant woman may rise. In most cases, the condition disappears after delivery. In others, the condition may persist and long-term follow-up and treatment of the diabetes is required. A repeat oral glucose test (OGTT) for diabetes will be performed six weeks after delivery.

It is not clear why some pregnant women develop GDM and others do not. A woman's risk for developing gestational diabetes increases if she:

  • Is over the age of 35 when she became pregnant
  • Is overweight before she became pregnant
  • Has pre-diabetes before she became pregnant
  • Has a family history of diabetes
  • Has high blood pressure
  • Had a previous pregnancy which led to an unexplained miscarriage or stillbirth; or the birth of a baby who weighed over four kilogrammes

Question by viviand (reposted by Forum Admin)

Hi Dr Tan

What can happen to my unborn baby – I am now 15 weeks pregnant – if I get gestational diabetes? Do all pregnant women get this condition? Can it be prevented, if so, how? Thank you.

Answered by Professor Tan Kok Hian, Head and Senior Consultant, Perinatal Audit & Epidemiology Unit, KK Women’s and Children’s Hospital.

The International Diabetes Federation estimates that one in seven births are affected by gestational diabetes mellitus (GDM) worldwide.

Diabetes can happen in pregnancy when the body does not produce adequate amounts of the hormone insulin to deal with sugar control during pregnancy. As a result, the sugar levels in the pregnant woman may rise. In most cases, the condition disappears after delivery. In others, the condition may persist and long-term follow-up and treatment of the diabetes is required. A repeat oral glucose test (OGTT) for diabetes will be performed six weeks after delivery.

It is not clear why some pregnant women develop GDM and others do not. A woman’s risk for developing gestational diabetes increases if she:

  • Is over the age of 35 when she became pregnant
  • Is overweight before she became pregnant
  • Has pre-diabetes before she became pregnant
  • Has a family history of diabetes
  • Has high blood pressure
  • Had a previous pregnancy which led to an unexplained miscarriage or stillbirth; or the birth of a baby who weighed over four kilogrammes

If GDM is detected early and managed timely and appropriately, the mother and child will usually have a good outcome. Type 2 diabetes mellitus (T2DM), if not detected early or not well-controlled, can be associated with permanent complications to the kidneys, eyes and blood vessels.

There is evidence that certain lifestyle changes to diet and exercise can help delay or even prevent the development of T2DM after GDM. Follow-up after delivery is therefore important for detecting persisting or the onset of T2DM, in order to achieve prompt and optimal control and treatment of the condition.

Poorly controlled or untreated gestational diabetes can put the mother and her baby at risk of the following:

Risks of gestational diabetes for the baby:

  • Excessive weight at birth > four kilogrammes (macrosomia)
  • Fetal abnormalities
  • Sudden fetal death
  • Fetal respiratory distress syndrome      
  • Low blood sugar or hypoglycemia after birth      
  • Jaundice after birth
  • Type 2 diabetes later in life

Risks of gestational diabetes for the mother:

  • High blood pressure/preeclampsia and eclampsia during pregnancy
  • Urinary tract infection
  • Premature delivery
  • Caesarean delivery
  • Gestational diabetes in future pregnancy
  • Type 2 diabetes in future


See previous page for information on Professor Tan Kok Hian.

Ref: N18