Pregnancy & Diabetes


Insulin is a hormone produced by the pancreas and it helps the muscles and organs take up the blood sugar that is needed to function properly. 

With Diabetes mellitus, the blood sugar level is raised because of a lack of insulin.  

Diabetes varies markedly in different ethnic groups and there is a high prevalence in Asiatic people and urban dwellers.  1% of pregnant women under the age of 35 will have diabetes or impaired glucose tolerance.

Due to advances in medicine, most diabetic women have perfectly healthy babies.  The key to a safe pregnancy is pre-conceptual planning and tight control of blood sugar levels. These levels change significantly throughout pregnancy.

Types of Diabetes

Insulin-dependent diabetes

Type 1 Diabetes

Insulin-dependent diabetes is diagnosed during childhood and sufferrers need insulin injections daily.

Non-insulin dependent diabetes

Type 2 Diabetes

Non-insulin dependent diabetes is more common in older people (>40 years) and who are overweight. Diet and medication control this type of diabetes.

Gestational Diabetes

Gestational Diabetes

Gestational diabetes develops during pregnancy and may persist after the birth.

Gestational Diabetes develops during pregnancy and may persist after the birth. Due to advances in medicine, most diabetic women have healthy babies.

Symptoms of Diabetes

  • Polyphagia – eating a lot
  • Polydipsia – drinking a lot
  • Polyuria – urinating a lot
  • Weight loss
  • Increased blood glucose levels
  • As a result of the pregnancy, Type 1 diabetics are likely to need more insulin due to the hormones that have an anti-insulin effect.
  • When blood sugar levels are too low to provide energy, fat is burned, producing ketones.  This causes bad breath, stomach cramps, vomiting and unconsciousness
  • Hypertension may develop, leading to pre-eclampsia and eclampsia
  • Premature labour may occur due to the size of the baby and an excess of amniotic liquid
  • A diabetic woman is more susceptible to thrush and urinary infections 

Planning to have a baby?

If you are planning a baby, but were diagnosed with diabetes, you may have special health concerns. The pregnancy will affect your blood sugar levels and diabetes medications.

Tips when diabetic and planning a pregnancy

  • Get expert advice from your physician or obstetrician, to determine if your diabetes is controlled enough to stop the contraceptive use.
  • Don’t be concerned if they test your urine or perform a kidney function test. This is necessary to help prevent complications during pregnancy.

The medical practitioner may also test or assess the following:

  • Cholesterol and triglyceride blood tests
  • Eye exam to see if you have glaucoma, cataracts, or retinopathy
  • Electrocardiogram 
  • Blood work to make sure your kidneys and liver are working
  • Foot exam

Many women don’t know they’re pregnant until the baby has been growing for 2 to 4 weeks. That’s why you should have good control of your blood sugar before you start trying to conceive.

Keep blood glucose levels within the ideal range:

  • 70 to 100 mg/dL before meals
  • Less than 120 mg/dL 2 hours after eating
  • 100-140 mg/dL before your bedtime snack 
  • Use your meals, exercise, and diabetes medications to keep a healthy balance.

Why is blood sugar control necessary in pregnancy?

High blood sugar levels early in the pregnancy (before 13 weeks) can cause birth defects. They also can increase the risks of miscarriage and diabetes-related complications.

How does the blood glucose change during pregnancy?

From the 10th week of pregnancy your blood glucose lowers because of the increased levels of estrogen and progesterone in blood. These pregnancy hormones stimulate the production of insulin.

From the second trimester, all pregnancy hormones increase, especially the placental hormones; this leads to an increased resistance to insulin. For this reason, insulin is less effective in regulating blood glucose, especially at night. 

If you use insulin to control your diabetes, your doctor can tell you how to adjust your dose. Your body will probably need more while you’re pregnant, especially during the last 3 months.

Labour can be a stressful time for you and the baby. If you’ve been using insulin during your pregnancy, insulin needs will continue through labour. It’s typically continued with an IV or with a pump if you are already on a pump. Right after delivery, your need for insulin will likely drop quickly.

Gestational Diabetes

Gestational diabetes means that the diabetic condition developed in pregnancy because the pancreas could not meet the increased need for the blood-glucose regulating hormone insulin. This result in poorly controlled blood glucose levels because insulin is not being made in enough amounts.  

When gestational diabetes develops, the pregnancy will be regarded as “high-risk” because the risk for developing hypertension (high blood pressure), blood clots, kidney disease and diabetic retinopathy [eye problems] increases.

How to prevent gestational Diabetes

  • Eat 3 medium sized meals per day.
  • Do not eat more than 2 snacks per day.
  • Balance the amounts of carbohydrates, fats and proteins in your meals.
  • Eat ample quantities of fruits and vegetables.
  • Eat reasonable quotas of lean meats and unsaturated fats.
  • Eat adequate portions of whole grains.
  • Avoid sugary foods in diet, e.g. sweet drinks, fruit juices, desserts, etc. 
  • Read the ‘Nutrition Facts’ panel to make healthier grocery choices.

What is the effect of diabetes on the baby?

  • The blood high in glucose passes to the baby via the placenta.  Blood glucose is the baby’s main food source.
  • The baby increases insulin production to utilize the glucose.  
  • Unused glucose is laid down as fat.  Your uterus will be bigger than average. Some babies are too big to be delivered vaginally, and you’ll need a cesarean delivery or c-section. Your doctor or midwife will keep an eye on your baby’s size so you can plan for the safest way to give birth.
  • The baby grows larger than normal, which may pose problems during delivery. This condition is called Macrosomia. 
  • After birth, the baby may have breathing problems because of lung immaturity and may also suffer from dangerously low blood sugar levels because of his own high levels of insulin.
  • Many hospitals keep an eye on babies of mothers with diabetes for several hours after birth and a drip may be considered because of dangerously low blood sugar levels right after they’re born. Their insulin is based on your high sugar, and when it’s suddenly taken away, their blood sugar level drops quickly and they’ll need glucose to balance it out. 

How is gestational diabetes detected?

Every pregnant woman should be tested for diabetes mellitus during their first antenatal visit and again between 16-28 weeks of gestation to identify those women at risk.

  • You must take a urine sample to each ante natal visit, and if the health professional doesn’t seem to think it’s necessary to test the urine, ask why?
  • The urine will be tested and the presence of glucose in the urine may be a sign of gestational diabetes.  The diagnosis, however, will be confirmed by means of a blood test (glucose-tolerance test). 
  • On confirmation, you will require special care and treatment to prevent complications from developing. Usually, dietary changes control the condition, but sometimes insulin may be required.  The key to diabetic control is to stabilize the blood glucose levels.

Managing Gestational Diabetes

Because of the risks for you and your baby, antenatal care is essential. You should go for a consultation as soon as you suspect a pregnancy.  If you are a known diabetic or has a BMI of more than 35, you need to consult with the medical practitioner before you conceives. Birth defects can substantially be minimized by proper control of blood sugar levels.

  • Monitoring the diet can help to control the blood sugar levels and diabetics should consult a nutritionist if she plans to conceive.
  • To avoid low blood sugar levels or “spiking” the mother must eat well balanced meals with additional healthy snacks between meals. Constant intake is important but without refined sugar. All food should be weighed and additional fiber should be added.
  • Exercise moderately.
  • Stick to the insulin regimen if prescribed.
  • Consultations should not be missed and a sudden increase in the size of the baby should be investigated 
  • When diagnosed: Monitor blood glucose levels before and after meals.
  • Test urine daily for ketosis (where the body burns fat as fuel).
  • Check eyesight every 3 months for the development of diabetic retinopathy.
  • Keep a daily “kick-chart” of the baby’s movement, especially after 36 weeks
  • If possible, monitor the baby’s heartbeat with a portable monitor (Doptone) from 30 weeks.

Will you carry your Baby to Term?

Women with well controlled diabetes often go full-term without any problems. However, many doctors prefer to plan for an early delivery, usually around weeks 38-39.

Breastfeeding and Gestational Diabetes

Dr Diana du Plessis

Dr Diana du Plessis

Diana du Plessis is an independent Midwifery consultant and researcher. She specializes in midwifery and neonatology and lectures widely to nursing professionals and academic audiences on a national and international level.

She is a passionate childbirth educator and national spokesperson on breastfeeding. She is the author and co-author of various nursing and midwifery publications (books and peer-reviewed articles).