Gestational Diabetes and Induction
Gestational diabetes (GD) was once a relatively rare condition, occurring in about 4% of pregnancies.
In recent years, the rate of women developing GD has doubled, and experts believe the incidence of the disease will keep increasing.
Most women with GD are told by their care providers they will need to be induced before their due date, destroying their hopes for a natural and intervention free birth.
Having GD can have a big impact on mothers’ and babies’ health during pregnancy, but does it really need to change how we give birth?
What Is Gestational Diabetes?
Gestational diabetes is a condition that only occurs during pregnancy. Certain pregnancy hormones interfere with your body’s ability to use insulin. Insulin converts blood sugar into usable energy, and if this doesn’t happen, blood sugar levels rise. Insulin resistance can cause high blood glucose levels and can eventually lead to gestational diabetes.
Some women will have symptoms of GD, while others will have none. Many women can manage the condition without treatment other than dietary and exercise changes. Around 20% of women will need insulin injections. So for many women, well managed diabetes means they can still have healthy babies and normal births.
Induction Of Labour
Many care providers routinely recommend that women with gestational diabetes be induced around 38-39 weeks. The most common reasons given for induction at this gestation are to prevent stillbirth, and to prevent babies growing too large for vaginal birth.
However, the evidence related to induction for women with GD comes from the review of one trial, which looked at 200 women who had either GD, Type 1 or Type 2 diabetes.
The World Health Organization states this evidence for induction before 41 weeks’ gestation is weak, and induction before 41 weeks should not be suggested if gestational diabetes is the only medical issue.
The American Congress of Obstetricians and Gynecologists (ACOG) guidelines for gestational diabetes also do not recommend induction of labour before 39 weeks for women with well controlled GD.
The evidence for induction of labour is neither strong, nor clear. A recent review looking at the evidence supporting indications for induction concluded there wasn’t strong enough evidence for induction of women with gestational diabetes.
Why Would I Be Induced?
There are several reasons why care providers will recommend induction for women with GD. What is important to remember is that many of these complications are more relevant to those women whose condition is not well managed.
A large baby (macrosomia) is considered to be a problem if you have gestational diabetes. The extra sugar in your bloodstream crosses the placenta and triggers your baby to make more insulin. This can cause your baby to store more fat and tissue and be larger than average (over 4.5kg).
It’s not possible to diagnose macrosmia before birth. Doing ultrasound scans in the third trimester allows care providers to make an educated guess, but the estimated weight prediction can vary from the actual birth weight by up to 15%.
In the US 10.4% of babies weigh more than 4 kg at birth. If you have GD, there is a 13.7% chance of having a baby over 4 kg, so the risk of having a large baby is increased, but not by a great deal. Keeping your GD well managed can reduce that risk of a large baby by up to 50%.
If care providers believe a baby is already large for gestational dates, they might suggest early induction to avoid a c-section later. This is due to a fear of shoulder dystocia, which is when the baby becomes stuck in the pelvic outlet because his shoulders are too wide to pass through. Most care providers consider this a medical emergency, needing interventions — such as episiotomy, forceps or vacuum delivery, or emergency c-section.
Even though shoulder dystocia can be prevented and managed by a care provider, it sometimes results in a nerve injury called brachial plexus injury. This injury can also occur in babies who don’t have shoulder dystocia, and even after elective c-section. Death from lack of oxygen due to shoulder dystocia is possible but it’s extremely rare.
The risk of stillbirth is higher for women with Type 1 or Type 2 diabetes and this is often used as an indication for induction for women who have gestational diabetes. High blood sugar can cause blood vessel damage to the placenta, which means poor oxygen and nutrient supply to the baby. This can lead to health complications for the baby, or to stillbirth or death.
However, these complications rarely occur in pregnancies where gestational diabetes has been diagnosed and is well managed.
Pre-eclampsia is a condition which involves a combination of hypertension (raised blood pressure) and the presence of protein in the urine during pregnancy. The condition usually occurs after 20 weeks gestation and affects about 3% of all pregnancies. Around 3% of cases occur without gestational diabetes, and just over 6% occur with GD.
Most cases of pre-eclampsia are mild and, if managed, have no effect on the pregnancy or the baby. Management usually involves lowering blood pressure by diet, exercise or medication. Continuing high blood pressure can reduce blood flow to the placenta. This means less oxygen and nutrients for the baby, which can lead to preterm labour, low birth weight, growth restriction or even stillbirth.
In some cases, the condition becomes more severe and develops into eclampsia, which occurs in 1-2% of pregnancies. Eclampsia can cause placental abruption, seizures, or preterm labour, and can be fatal to mother and baby. The only way to cure pre-eclampsia is for the baby to be born.
Induction for pre-eclampsia is usually recommended at 37 weeks, as it’s believed this reduces the risk of complications. A study of pregnant women with mild pre-eclampsia found induction of labour between 34-37 weeks reduced the small risk of adverse maternal outcomes. However, the risk to the baby was increased, including complications of preterm birth such as respiratory distress syndrome.
If you have been diagnosed with pre-eclampsia and have GD, discuss with your care provider the benefits and risks of expectant monitoring and management of your condition.
What If I Need To Be Induced?
Despite your best attempts to avoid it, induction might become medically necessary if you have gestational diabetes. This can challenge your attempts to have a natural birth, but you might avoid further interventions and a c-section. There’s a number of ways labour can be induced and, depending on the urgency of your situation, you might be able to negotiate as little intervention as possible.
During labour, your blood glucose will be monitored every hour to ensure it stays within safe levels. If your gestational diabetes has remained under control during pregnancy, through diet and exercise, it’s unlikely your blood glucose levels will rise. If you have been treated with insulin it’s more likely your blood glucose will increase during labour and, if that happens, you might need to have insulin and glucose administered through a drip.
Your baby will need continuous monitoring if medical forms of induction such as Pitocin or Syntocinon are used. This is because artificial oxytocin can cause your uterus to contract strongly and cause your baby to become distressed. Continuous monitoring will limit your ability to move, and might make it harder for you to cope with contractions. You can request an epidural, which might lead to further interventions and c-section.
If you are able to avoid these methods of induction you might have intermittent monitoring. Induction is challenging to cope with, but if you have good support from your care provider and birth team, you can have a positive birth experience.
Gestational diabetes is now more commonly diagnosed, but it doesn’t have to mean a highly interventive birth. If your condition can be managed, you should be able to have a normal birth. If induction is necessary, make sure you are well informed about the reasons. All medical intervention comes with risks, so it’s important your care provider answers your questions, and you take the time to make the decision that is best for you.