Gestational diabetes

By the time you get to about 24 weeks (ie six whole months of being pregnant) you could be forgiven for thinking that the riskiest stretch of pregnancy might be behind you.Pregnant woman holding belly

But for some pregnant women (between about 2% and 14%) a new health issue can loom on the horizon after this point in the form of gestational diabetes.

Gestational diabetes is when you have too much sugar in your blood because your body can't produce enough insulin (which converts blood sugar into energy) to meet the extra demands of pregnancy - ie incubating a growing baby and hormones produced by the placenta that resist insulin.

Risk factors for gestational diabetes

  • Being overweight
  • Already having had a large baby (4.5kg or more)
  • Previously having had gestational diabetes
  • Family history of diabetes (a parent, sibling or child with diabetes)
  • Family origin with a high prevalence of diabetes (South Asian, Middle Eastern or black Caribbean descent)


Symptoms of gestational diabetes

  • Excessively thirsty
  • Weeing a lot
  • Tired
  • Experiencing blurred vision

If sugar is detected in your urine during a routine antenatal check, you'll probably be sent for an oral glucose tolerance test (OGTT).

This Mumsnetter explains: "First you have to have a glucose test by fasting for several hours then they test your blood and urine for raised sugar levels. Based on these results you may be able to control diabetes by what you eat, ie no sugars, fewer carbs etc or, like me, have insulin injections several times a day and record everything you eat! Very boring!! But the good news is in nearly all cases it dissapears after baby arrives, as it did with me."

How the oral glucose tolerance test works

  • You eat normally in the days leading up to the test
  • The evening before the test you stop eating before 10pm and don't have anything to eat or drink, except water, until the test the next day
  • At the clinic you'll give a blood sample that will be used to measure your blood sugar level after fasting (a baseline test)
  • You'll be asked to drink a very sweet, sugary mixture and after a gap your blood sugar level will be tested and compared with the normal range

How gestational diabetes affects your baby

Gestational diabetes can lead to your unborn baby piling on the the pounds, particularly around the shoulders, chest and abdomen (known as macrosomia or 'of large body').

This can make giving birth vaginally difficult as your baby having large shoulders doesn't help what's already a tight squeeze.

Very large babies are more likely to be induced and to need delivering by caesarean, but not all women with gestational diabetes have large babies.

Your baby may also be born with low blood sugar (hypoglycaemia) but this doesn't mean they have diabetes.

How gestational diabetes affects you

It's daunting to be told you have gestational diabetes, but there are plenty of Mumsnetters who've been through it before you and lots of support threads on Mumsnet Talk to share experiences and advice.

The good news is that it usually disappears once you've given birth and it can be controlled by diet and exercise, although if it can't you'll need to inject insulin.

The bad news is that once you've had gestational diabetes there's an increased risk you'll develop it in subsequent pregnancies and that you'll develop type 2 diabetes later in life.

What Mumsnetters say about gestational diabetes

  • I managed to control it by diet. I had to see a diabetes consultant and be taught how to check my glucose levels, be given advice on diet etc, and had to check my glucose levels six times a day (ran out of fingers that weren't sore very quickly!) and saw the midwives and a diabetes nurse every two weeks. I had to keep a food diary so that the diabetes nurse could check it out. You may need insulin if your diabetes can't be controlled by diet alone, but usually the diabetes goes away after you deliver and the insulin can be stopped. WigWamBam
  • I had gestational diabetes (GD) diagnosed late in second pregnancy (36 weeks) and ended up giving birth to a baby just shy of 11lbs - at home, thank goodness, and all was well. I was told by the diabetic specialist that it's not really understood why some women with GD have giant babies and others don't. DS was definitely not just a normal 'big' baby - he very much looked like a child who'd had too much sugar in the womb: massive cheeks, huge chest and stomach, double chin, man boobs. He wasn't especially long and his head circumference was average. Fabsmum
  • They recommend low GI foods, look for low GI symbol on packets, and have carbohydrates with each meal eg wholegrain/multigrain bread not white, eating five small meals. It's all a matter of trial and error, and once you understand what does and doesn't work for you you will be better able to control your blood sugars. I recommend investing in a couple of good diabetic cookbooks though as they can give you some diversity in what can otherwise be a really boring diet given what you can't eat being pregnant and diabetic. Mum26plus

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Last updated: 24-Jul-2013 at 3:30 PM