Diabetes and pregnancy

A question that many women ask is, “Can I have a baby if I have diabetes?” This is a very important question. If the pregnancy is not planned and managed correctly, the pregnancy outcome can be harmful to both mother and baby. Dr Louise Johnson explains further.

There are two types of situations that can occur: healthy pregnant women that develop diabetes during pregnancy or diabetes patients (women) that wish to fall pregnant. It is best to look at these topics separately.

Healthy women that develop diabetes

This type of diabetes is called gestational diabetes mellitus (GDM), and the risk factors for developing GDM are:

  • Being older than 35 years.
  • Having a close family member, such as a mother or father, with Type 2 diabetes.
  • Having had GDM in a previous pregnancy.
  • Being overweight with a BMI (body mass index) of over 30kg/m2.
  • Having polycystic ovarian syndrome (PCOS).
  • Having complications in a previous pregnancy with a baby larger than 4,5kg, a still born baby, or a baby with malformations.
  • Women who are of South Asian descent.

GDM has an incidence of 4% in all pregnancies. It usually develops during the second trimester; in this time, the body changes due to the adjustment in hormones and begins to be more insulin resistant. This is like the insulin resistant state of Type 2 diabetes.

As the pregnancy advances, the insulin resistance becomes worse and patients may need insulin temporarily during the last few weeks before delivery. This need will go away after the birth of the baby. The problem with insulin resistance during the last part of the pregnancy is that the body cannot produce enough insulin to manage the higher glucose levels. This glucose gets transferred to the baby and causes the baby to gain too much weight.

There are recommendations from the American Diabetes Association (ADA) that all pregnant women should be screened for GDM at week 24 with an oral glucose tolerance test (OGTT). This test is where the mother fasts from 10pm at night then at 8am the next morning, blood is drawn, she then consumes 75g of glucose and blood is collected again after an hour and then after two hours. This helps the doctor to pick up GDM early, preventing a big baby.

You will be diagnosed with GMD, if your OGTT test results are as follows:

  • Fasting glucose is more than 5,1mmol/L.
  • First hour value is more than 10mmol/L.
  • Second hour value is more than 8,5mmol/L.

The dangers of GDM are twofold: the mother can develop Type 2 diabetes about six to ten years after the pregnancy. It is important for the mother that had GDM to stay on a diabetic diet and get yearly check-ups to diagnose diabetes early, if she does develop it.

The baby will also have a higher risk to become obese, especially if it was born weighing more than 4,5kg. This baby has a risk of developing diabetes a lot earlier, even in childhood. Again, living a healthy lifestyle is important.

The risk of complications during pregnancy is the same as a mother with Type 1 or Type 2 diabetes, except there is no increased risk of organ malformations in these babies since the organs formed when the glucose levels were still normal. In the healthy female population, the risk of birth defects is 1-4%.

Patients with GDM should have a OGTT six weeks after delivery to determine if the raised glucose levels have returned to normal. Remember, the risk of developing Type 2 diabetes is more than 50%.

The diabetes patient (Type 1 or 2) that wishes to fall pregnant

The most important factor in this pregnancy is planning. Both Type 1 and Type 2 diabetes patients should only become pregnant once they have a HbA1c test result of 6,5% for three continuous months. This is important for healthy eggs and conception.

The first seven weeks are extremely important to have normal glucose control as this is the time that the baby’s organs are formed. Abnormal glucose control during this period increases the risk of birth defects and miscarriages.

More than 50% of women who have diabetes become pregnant without planning. It is vital to use effective family planning to prevent this and to plan for a healthy pregnancy.

Pre-pregnancy examinations:

  • Do the HbA1c test to determine if your result is at the correct target – 6.5% or lower.
  • Test your blood pressure, kidneys and the nerves of the feet.
  • It is important that an eye specialist does a thorough eye examination before the pregnancy and every trimester to prevent eye damage. Laser treatment may be necessary.
  • Check the functionality of the thyroid, especially in Type 1 diabetes. An underactive thyroid can cause a floppy baby.
  • Review all the current medication and stop medication that can be harmful to the baby such as angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) and statins. This should be substituted with ‘baby friendly’ drugs as recommended by your physician.
  • Type 1 diabetes with difficult control will usually be switched to an insulin pump for the period of three months before and during the pregnancy. Type 2 diabetes will usually be started on insulin first, as a baseline, once a day and as time progresses a short-acting insulin will be introduced before each meal. Most oral medications are not safe in pregnancy, except for metformin.

It is important to be vigilant in checking blood glucose often (before each meal and 90 minutes after each meal). There are also devices available, such as Dexcom continuous glucose monitoring, that can help with this.

Type 1 diabetes with difficult control will usually be switch to an insulin pump for the period of three months before and during the pregnancy. Type 2 diabetes will usually be started on insulin first, as a baseline, once a day and as time progresses a short-acting insulin will be introduced before each meal. Most oral medications are not safe in pregnancy, except for metformin.

Blood glucose control is essential because of the risk of complications to the mother and the baby that increases dramatically with poor control.

Risk for mother:

  • Worsening of diabetic eye problems.
  • Worsening of diabetic kidney problems.
  • Increase in infections in the bladder and vaginal area, which can cause early labour.
  • Preeclampsia (a condition in pregnancy characterised by high blood pressure, sometimes with fluid retention and proteinuria).
  • Difficult delivery or caesarean section.

Risks for the baby:

  • Premature delivery.
  • Birth defects (not an increased risk for the GDM mother).
  • Macrosomia (big baby).
  • Possible damage to the nerve of the arms if the baby is big and delivered vaginally.
  • Low blood glucose at birth.
  • Prolonged jaundice.
  • Respiratory distress syndrome (difficulty in breathing).
  • Twitching of the hands and feet due to low calcium and magnesium, which is a direct effect of uncontrolled glucose.

What should the glucose target be during pregnancy?

• HbA1c result below 6%. • Fasting glucose 3,5-5,9 mmol/L. • One hour post eating <7.8 mmol/L.

After the pregnancy

Patients with Type 1 and Type 2 diabetes can breastfeed if there is no sight-threatening bleeding or the possibility thereof in the eyes.

Advice for women with diabetes who breastfeed:

  • Breastfeeding will make the glucose a bit more difficult to predict because there are carbohydrates that are going to the baby through breastmilk.
  • Check the glucose before breastfeeding and if below 5mmol/L, eat a 15g snack.
  • Keep a snack ready to eat, to prevent having to interrupt the breastfeeding.
  • Drink enough liquids, especially water or caffeine-free tea, while nursing.
  • Low blood sugars are much more common during night-time nursing. Add a snack or reduce night-time medication. Discuss this with a doctor.

Insulin needs fall dramatically after delivery and medication should be adjusted to prevent hypoglycaemia (low blood glucose). Contraception should also be discussed for future planning.

Another question that is normally asked, “What is my child’s risk of getting diabetes?”

If the father has Type 1 diabetes, the risk is 8-9%.

If the mother has Type 1 diabetes, the risk is 2-3%.

If the father has Type 2 diabetes, the risk is 15%.

If the mother has Type 2 diabetes, the risk is 15%.

If both parents have Type 1 diabetes, the risk is less than 30%.

If both parents have Type 2 diabetes, the risk is 75%.

Final thought

My advice to the diabetic mother and her partner is to follow the rules and consult with the healthcare providers regularly and the beautiful reward for the perseverance will be a healthy baby. I know this is a lot of hard work but there is a silver lining. After this pregnancy, you will have learned how to take control of your health and have had the opportunity to develop healthy habits, which you can take with into your future for you and your family.


  • Amod A, Motala A, Levitt N et. al. (2012) ‘The 2012 SEMDSA guideline for the management of type 2 diabetes.’ JEMDSA, 17 S1-94.
  • Dornhorst A, Banerjee A (2010) ‘Diabetes in pregnancy. Textbook of diabetes 4th edition, Oxford Wiley Blackwell.
  • Metzger BE, Gabbe SG, Persson B et. al. (2010) ‘International association of diabetes and pregnancy study group consensus panel. International association of diabetes and pregnancy study groups recommendations on the diagnosis and classification of hyperglycaemia in pregnancy.’ Diabetes Care, 33 p676-82.
  • Sacks D. (2011) ‘Diabetes and pregnancy: a guide to a healthy pregnancy for women with type1, type 2 and gestational diabetes.’ 1st edition, American Diabetes Association Virginia.

MEET OUR EXPERT - Dr Louise Johnson

Dr Louise Johnson
Dr Louise Johnson is a specialist physician passionate about diabetes and endocrinology. She enjoys helping people with diabetes live a full life with optimal quality. She is based in Pretoria in private practice.