People who have never had any other type of diabetes may still develop diabetes in pregnancy. This is known as gestational diabetes, and whilst it will normally resolve itself once the pregnancy ends, it is important to understand how it impacts your pregnancy blood sugar levels and the health of both you and your baby. Appropriate management will minimise the risk of complications.
What is gestational diabetes?
Gestational diabetes is a type of diabetes that affects around four or five pregnancies in every 100. The exact mechanisms that cause it are unknown, but it is believed pregnancy hormones and other physiological changes may cause increased insulin resistance. This is when you produce insulin, but it does not work effectively.
Cases of gestational diabetes lead to pregnancy blood sugar levels above the recommended level, but rarely result in visible symptoms. There may be increased thirst, dry mouth, increased need to urinate, blurred vision, tiredness or genital itching, but many of these are more common during pregnancy generally. Screening for gestational diabetes in the UK is offered to people with one or more risk factors.
Risk factors for developing diabetes in pregnancy
Risk factors for gestational diabetes include a family history of diabetes of any type, or having had gestational diabetes during a previous pregnancy. Age is a factor, particularly being over 40, as is weight (NHS guidelines put the risk threshold at a 30 or more BMI)[https://www.nhs.uk/conditions/gestational-diabetes/]. Previous weight loss surgery, however, can also increase the risk. It is not just your weight, as if you have had a baby of 4.5kg (10lb) in the past, that is also a risk factor. People of Black, Asian or Middle Eastern heritage are more likely to develop gestational diabetes even if they have lived their whole lives in the UK.
Screening for gestational diabetes in the UK
A doctor or nurse should ask you questions at your first antenatal appointment to identify if you have any of these risk factors. This will usually take place when you have been pregnant between eight and 12 weeks. If you are at risk, you should be offered a blood test or what is known as an oral glucose tolerance test (OGTT). The OGTT is carried out between weeks 24 and 28 of pregnancy, unless you have experienced gestational diabetes previously, in which case it may be given earlier. You may also be offered an OGTT if a routine urine test detects high glucose levels.
The OGTT will involve you fasting and drinking nothing (except maybe water) for eight to ten hours. It is usually easiest to do this overnight. You will have an initial blood test in the morning, then be given a glucose drink. An hour or two later, another blood test will measure how your body is reacting to the glucose.
Complications of gestational diabetes
You are more likely to develop type 2 diabetes in future if you have experienced gestational diabetes. Although it rarely shows symptoms, gestational diabetes can also cause pregnancy complications such as pre-eclampsia (high blood pressure). Other possible complications include a larger than average baby (which in turn increases the likelihood of difficulty during delivery/needing a caesarean section). Polyhydramnios (excess amniotic fluid) can also cause delivery complications or prematurity. Prematurity is generally more common in pregnancies with gestational diabetes. Babies are also more likely to be born with jaundice.
Treatment for gestational diabetes
As with other forms of diabetes, gestational diabetes is generally treated by controlling your blood sugar. This starts with alterations to your diet and an increase in gentle exercise, though you should discuss these changes with your doctor or midwife first. NHS patients are given blood testing kits to allow them to monitor treatment effectiveness. If pregnancy blood sugar levels remain high, you may need to take metformin tablets or receive insulin injections. If you do not give birth by 41 weeks, you may need to be induced or receive a caesarean. As gestational diabetes puts you at greater risk of developing type 2 diabetes, you will also need to undergo regular checkups after your pregnancy.
If you have gestational diabetes in the UK, it can be managed effectively. Anyone with risk factors will be screened, even if they do not show symptoms, and advice and support are available. This ensures that the majority of people with diabetes in pregnancy remain healthy and give birth to healthy babies.
FAQs
What is the impact of diabetes in pregnancy on the mother and baby?
It is rare for gestational diabetes to show symptoms, though things like dry mouth, increased thirst and increased urination can occur. It can also cause larger babies to develop, contribute to complications such as pre-eclampsia and polyhydramnios, and make it more likely you will develop type 2 diabetes in future.
What are the risk factors for gestational diabetes?
Age and weight are two of the biggest factors. If you are older and heavier, you are at greater risk. Family history of any type of diabetes in your parents and siblings can also increase the likelihood of developing gestational diabetes, as can belonging to a higher risk ethnicity, as it is more common among people of Black, Asian and Middle Eastern heritage. Other risks include a history of gestational diabetes or larger babies in previous pregnancies.
How can you treat gestational diabetes?
Treatment for gestational diabetes focuses on controlling your blood sugar. This may mean making changes to your diet, or increasing how often you exercise. If your blood sugar continues to be high, you may need to take medication. Metformin can be given as tablets, but insulin must be delivered as an injection.
