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Gestational Diabetes Mellitus (GDM) is a condition that arises exclusively in pregnancy. Unlike other types of diabetes, it will usually go away on its own, with blood sugar levels returning to normal soon after birth. It may be rarely identified in the first-trimester blood tests, in which case it is likely you actually had diabetes before your pregnancy.

What is gestational diabetes and how do you avoid it?

Outside of pregnancy, carbohydrates are released as glucose into your bloodstream to be used as energy. Your body has a natural mechanism for reducing these levels and helping them to be stored in cells for use later; this is the hormone insulin.

During pregnancy, hormones produced by your placenta will make the insulin you produce less effective, meaning your body produces more insulin to help manage the rising sugar levels. We refer to this as insulin resistance and pregnancy creates this natural state. Your body will produce increasingly higher levels of insulin to compensate, but sometimes you may be unable to produce the required levels and the excess sugar levels can lead to hyperglycemia (high blood sugar levels) or glucose intolerance and ultimately GDM.

If left untreated, gestational diabetes can present significant risks for both you and your baby, so it’s essential to catch it early, manage your blood glucose levels, and attend regular checkups throughout your pregnancy. In this post, we’ll talk about common risk factors for the condition and cover all you need to know regarding how to avoid gestational diabetes in pregnancy to ensure that you have access to the most up-to-date, evidence-based information for an empowered pregnancy.

Risk factors for gestational diabetes

We still don’t know why some women develop GDM and others don’t, but we know that 1 in 10 women will develop gestational diabetes during pregnancy. Certain factors will make developing this condition more likely:

  • Obesity (BMI >30)
  • Ethnicity (Afro-Caribbean, SE Asian, Middle Eastern & Chinese populations have a higher risk)
  • Having experienced GDM in a previous pregnancy (around 40% chance of developing it in a subsequent pregnancy)
  • Family history in a first-degree relative (parent or sibling)
  • A previous baby weighing more than 4.5kg (9lb 9oz)
  • Having Polycystic Ovarian Syndrome (PCOS)

How is gestational diabetes diagnosed and treated?

If you have any of the risk factors listed above, you’ll be referred for a blood test between 24-28 weeks. You may also be referred for this test if your baby measures larger than expected on an ultrasound scan or if glucose is detected in your urine. It’s not the most pleasant of tests but relatively quick and essential for a diagnosis. Two blood tests will be taken, the first after you’ve had nothing to eat in the morning, the second will be taken 2 hours after you’ve had a sugary drink (which can taste a bit sickly). The purpose of the test is to see how your body copes with processing a high dose of sugar, and if you are above the threshold, you’ll be diagnosed with GDM.

Receiving a diagnosis of GDM may be upsetting, especially if you have a previously low-risk pregnancy. It will mean that you will suddenly have several interventions and that you’ll be seen and monitored in a specialist clinic with a dietician, an obstetrician, and in some cases, an endocrinologist.

There are several precautions you will need to take with gestational diabetes in pregnancy. You’ll be asked to monitor your blood sugars several times a day by pricking your finger and recording what you’re eating. From here, you will work out whether your sugar levels can be controlled with lifestyle measures such as diet and exercise is the first step of management. If your levels are still high despite these interventions, you will likely be advised to start a medication called metformin, which reduces glucose output by the liver by increasing the insulin sensitivity. If levels are still rising despite taking metformin, sometimes insulin injections will be recommended as well.

You may find it frustrating and upsetting if a medication is prescribed for you, especially if you’re trying your hardest to control your levels. It’s imperative not to blame yourself if you’re doing all you can with dietary modifications. Sometimes, despite your best efforts, additional help is needed. This is not a failing on your part; as the baby grows, the insulin resistance also increases, so medication may ultimately be required.

You would typically be recommended to have additional scans to monitor your baby’s growth and, depending on your baby’s size and how well your blood sugar is controlled, your medical team will more than likely recommend an earlier delivery (before 41 weeks at the latest).

Vaginal delivery is still very possible and not contraindicated. If your baby is thought to be very big (>4kg) then a cesarean birth may also be discussed, as there is an increased risk of shoulder dystocia (this is considered an emergency and occurs during delivery when the shoulder becomes stuck after the head has delivered).

What to expect after giving birth?

As we mentioned above, gestational diabetes will only affect you in pregnancy, during labour, and birth, and the condition will typically go away afterwards. To make sure, you will need to have a blood test six weeks after you deliver to check for type 2 diabetes (T2DM). This is because there is a significantly increased risk of you developing T2DM in later life (around 60%), being about two to three times more likely to develop it in the 5 to 10-year period after your pregnancy. Therefore, it’s essential to have annual checks for diabetes and also maintain a healthy weight and diet to reduce your chances of developing this condition.

Following the immediate period after birth, your baby may have some difficulty controlling their blood sugars as they have all the excess insulin floating around their body from pregnancy and therefore may have very low sugars (hypoglycemia). So your baby will need to have their blood sugars regularly monitored for 24-48 hours after birth. We also know that babies of mums who have diabetes in pregnancy have a higher risk of obesity. It may require a slightly extended stay in the hospital but, your medical team will provide you with all the information necessary for ensuring that gestational diabetes has as little impact on your baby’s life as possible.

How to avoid gestational diabetes in pregnancy

While risk factors such as family history and ethnicity can’t be modified, it’s important to remember that they do not necessarily mean you will develop gestational diabetes. If you do fall into the high-risk category, there are some steps you can take to prevent developing this condition in pregnancy; it’s not necessarily a foregone conclusion. So, what are our tips on how to avoid gestational diabetes in pregnancy?


First of all, educate yourself about this condition. Your hospital should help with this. Most GDM clinics involve input from a dietician, a diabetic specialist nurse, and an endocrinologist, as well as your obstetrician. Understanding what’s happening in your body and why controlling your sugar levels is essential should make it easier, empowering you to manage this yourself.

Maintaining a normal BMI

You can also aim to maintain a ‘normal’ BMI. Body Mass Index is a ratio of weight and height and is a less than perfect system, but a BMI of between 19 and 25 generally equates to a healthy target. Trying to avoid putting on more than the recommended amount in pregnancy will help prevent gestational diabetes. Your healthcare team will advise you if you have any concerns regarding your weight during pregnancy.


We know that a regular exercise routine pre-pregnancy and in early pregnancy will help reduce your risk of developing GDM, and maintaining this throughout pregnancy will also be beneficial. A 2015 systematic review of 2,800 women, published in BJOG, found that exercising in pregnancy reduced the risk of developing diabetes by 30% and up to 36% in those maintaining exercise throughout pregnancy. This was found to have the most benefit if women practice a variety of stretching, strength, and cardiovascular activity. Yoga provides excellent benefits during pregnancy and helps contribute to this exercise target.


A balanced and healthy diet is essential in both preventing and managing gestational diabetes.

  • Avoid heavily processed foods, those with a high GI index, i.e., refined sugars, and those that release their energy very quickly (white bread, pasta, and rice).
  • Instead, eat foods with high fibre content, so lots of grains, fruit, and vegetables will be beneficial.
  • Aim to combine protein or fats with carbohydrates during a meal; this will help slow the release of glucose into the blood.
  • Having small, regular meals throughout the day in place of eating fewer big meals can also help maintain a well-controlled blood sugar level.

We realise that coping with a diagnosis like gestational diabetes in pregnancy can be hugely overwhelming when you are doing your best to care for your growing baby. For those who already suffer from depression or anxiety, it can make it worse. Although this is a condition that needs to be closely managed, it’s important to remember that your medical team is at hand to help try not to overly focus on high readings and let them know if you need further support.

For more information about this condition and how to avoid gestational diabetes in pregnancy, please get in touch. If you have any concerns about your health or pregnancy, please contact your own healthcare provider. This must be managed by a professional who knows your individual case.