Risk Factors for Gestational Diabetes

7 min
Updated Oct 30th, 2023

Gestational diabetes affects at least 4-5 in 100 women during pregnancy, which means that it’s pretty common. Although gestational diabetes can have serious consequences, if the condition is well managed the risk of any problems is lowered. Those who have gestational diabetes during their pregnancy can and do have healthy pregnancies and healthy babies.

What is gestational diabetes?

Throughout your pregnancy, your placenta produces hormones that result in glucose building up in your blood. Normally, your pancreas provides enough insulin to manage it (insulin is the hormone which helps to manage your blood sugar levels). But if your body stops using the insulin or can’t produce enough, your blood sugar levels rise. Gestational diabetes occurs when high blood sugar develops during pregnancy, usually disappearing after giving birth. Gestational diabetes can happen at any time during your pregnancy, but is more likely in the second or third trimester.  

What are the symptoms of gestational diabetes?

Gestational diabetes doesn’t usually cause any symptoms. Most cases are only discovered when your blood sugar levels are tested during screening for gestational diabetes. You’ll be screened for gestational diabetes if you’re in any way at risk (we talk more about those risk factors below). Although some women might not notice any symptoms at first, they may go on to develop recognisable symptoms if their blood sugar levels gets too high (hyperglycaemia), such as:

  • An increased thirst
  • A dry mouth
  • Weight loss (without trying to)
  • Feeling more tired than usual
  • Needing to urinate more frequently (especially at night)
  • Thrush or general itching

As some of these symptoms are normal to feel in pregnancy (feeling tired or needing to pee when the baby presses on your bladder, for example!) It’s important that you tell your midwife or GP if you are concerned about any symptoms you may be experiencing. 

As gestational diabetes can be symptomless, your midwife will ask you some questions around week eight to 12 of your pregnancy to judge whether you’re at risk. If you have one or more risk factors then you will be asked to complete a screening test called an oral glucose tolerance test (OGTT) between 24 and 28 weeks.

The OGTT takes about two hours. It’s not much of a bother and it’s worth it to ensure that your pregnancy and baby is healthy. You’ll simply have a blood test in the hospital at a morning appointment when you haven’t yet eaten. After which you’re given a glucose drink and you can rest for a couple of hours until they test your blood sugar level again. 

Who is at risk for gestational diabetes?

People who are overweight

A BMI of 30 or above means you are very overweight, or obese. Women who have a BMI above 30 at the start of their pregnancy are more likely to develop complications during their pregnancy, labour and birth.

If you have a BMI of over 30 you’re more likely to develop gestational diabetes and that risk increases the higher the BMI. If your BMI is over 30, your GP may advise a higher dose of folic acid than usual, which you should take for at least three months before you become pregnant. 

Ideally, it is advisable to ensure that you are a healthy weight before you start trying for a baby.

People with prediabetes

Prediabetes occurs when your blood glucose levels are higher than normal but not high enough to be diagnosed with diabetes. As your blood sugar level is above the normal range, your risk of developing gestational diabetes and fully developed diabetes is higher. If left untreated, diabetes can get progressively worse.

People with polycystic ovary syndrome (PCOS)

Women who do get pregnant with PCOS need to be aware that their risk for gestational diabetes is higher. This is because PCOS is strongly associated with insulin resistance and high blood sugar. Because of this risk, pregnant women with PCOS may be tested for gestational diabetes earlier than at the routine 24-28 weeks.  Taking Inofolic Alpha throughout pregnancy would be a good place to start. It also contains all the folic acid that you need.

People who had gestational diabetes during a previous pregnancy

It is common for women who have had gestational diabetes during a previous pregnancy to get the condition again in following pregnancies. Fortunately there are many ways of reducing the risk the next time around. Before you start trying for a baby you can ask your GP to help advise you regarding a diet and exercise plan. 

If you’ve had gestational diabetes before, your midwife will arrange an early glucose tolerance test to test your glucose levels before 20 weeks.

People who previously delivered a baby weighing more than nine pounds

If you’ve previously delivered a baby weighing more than nine pounds you’re at higher risk of developing gestational diabetes with your next pregnancy. You’re also at risk of having another large baby again if you have gestational diabetes. A high blood sugar level can cause your baby to become larger. This increases the risk of the baby becoming stuck in the birth canal and obtaining birth injuries. It also increases the chance of you needing a C-section delivery. 

People who are a certain race or ethnicity

If you have a Black, African Caribbean, Middle Eastern or South Asian background then you’re at a higher risk of developing gestational diabetes.

How gestational diabetes can affect your pregnancy?

Anyone’s main concern during their pregnancy is that their baby will be OK. So if you’re diagnosed with gestational diabetes during your pregnancy it can be a worry. This is because there are certain risks associated with gestational diabetes:

  • A bigger baby, which can cause birth complications
  • A higher risk of stillbirth (although rare)
  • Premature birth
  • A condition called polyhydramnios where there is too much fluid surrounding the baby in the womb (amniotic fluid) which can cause premature labour or complications with delivery
  • Pre-eclampsia which can be life-threatening for mother and baby if not treated
  • Your baby developing low blood sugar after birth
  • Your baby developing jaundice after birth

You will also be at a higher risk of developing diabetes 2 in the future. However, if you do develop gestational diabetes then you and the baby will have extra health checks and will be closely monitored. Most women with gestational diabetes have healthy babies.

There are many risk factors that affect the probability of developing gestational diabetes in pregnancy. Some are not within your control, but with others, you can make positive changes before you start trying for a baby.

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