What is Gestational Diabetes?
Gestational diabetes (GD) is high blood sugar (glucose) that develops during pregnancy and usually disappears after giving birth. It can happen at any stage of pregnancy but is more common in the second or third trimester. It happens when your body cannot produce enough insulin – a hormone that helps control blood sugar levels – to meet your extra needs in pregnancy.
Who can develop Gestational Diabetes?
Anybody can develop GD but you are more likely to develop it if :
- your body mass index (BMI) is above
- you previously had a baby who weighed 4.5kg (10lb) or more at birth
- you had gestational diabetes in a previous pregnancy
- 1 of your parents or siblings has diabetes
- you are of south Asian, Black, African-Caribbean or Middle Eastern origin (even if you were born in the UK)
If you have 1 or more risk factors for gestational diabetes you should be offered a screening test called an oral glucose tolerance test (OGTT), which takes about 2 hours. You will be given a blood test in the morning when you have not had any food or drink (though you can usually drink water) for 8 to 10 hours. You’re then given a glucose drink and, after resting for 2 hours, another blood sample is taken to see how your body is dealing with the glucose.
The OGTT is done when you’re between 24 and 28 weeks pregnant. If you’ve had gestational diabetes before, you’ll be offered an OGTT earlier in your pregnancy, soon after your booking appointment, then another OGTT at 24 to 28 weeks if the first test is normal.
What are the risks of Gestational Diabetes?
Most women with GD will go on to have normal healthy pregnancies and births and it is important to remember that most cases of GD are controlled by changes in diet and exercise. In more ‘severe’ cases there are medications that can be taken, and you may have to test your glucose levels regularly by pricking your finger and taking a reading. If this is the case, a special diabetic midwife will explain everything to you.
However, GD is associated with a higher chance of:
- your baby growing larger than usual which increases the likelihood of *induction being suggested or maybe a caesarean section
- Polyhydramnious – a larger than normal amount of amniotic fluid (the fluid that surrounds the baby) in the womb, which might cause premature labour or prevent the baby from getting into an optimum position for birth
- Premature birth – giving birth before the 37th week of pregnancy
- Pre-ecalmpsia – a condition that causes high blood pressure during pregnancy and can lead to pregnancy complications if not treated
- your baby developing low blood sugar or yellowing of the skin and eyes (jaundice) after he or she is born, which may require treatment in hospital
- and in very rare cases, stillbirth
- an increased risk of developing type 2 diabetes the future
*Induction is often offered in cases when women are pregnant with a suspected ‘large’ baby, which is also one of the things your care givers will be concerned about if you are diagnosed with GD. However, it is worth noting that studies show ultrasound estimates of a baby’s possible weight and size cannot predict which babies will be larger and/or will have shoulder dystocia (when a baby’s shoulders get stuck on the way out) (Sara Wickham, 2022.)
The issue with diagnoses of GD is that guidelines, tests and cut-off points used to determine whether or not someone has GD varies between hospitals and areas (Sara Wickham, 2018) so you might be told you have it if you live in one area, but you wouldn’t be if you tested at a different hospital. Being labelled as having GD is problematic because it completely changes your pathway of care when, in some cases, it might not actually be necessary. If you are diagnosed with it, I urge you to read this article by Rachel Reed as it may help you discuss your options with your doctors, or, at the very least, give you a better idea as to what you are dealing with.