Expert / 6 July, 2021 / Joanne Paterson

Gestational Diabetes: What You Need To Know From Diagnosis To Birth And Beyond

What is gestational diabetes?

Gestational diabetes is diabetes which occurs during pregnancy in non-diabetic women.

ANY pregnant woman can be diagnosed with gestational diabetes, but certain women are at a higher risk.

You have a higher risk if you have any of the following:

  • body mass index (BMI) of 30 or more
  • previously given birth to a baby who weighed 4.5kg (10lbs) or more at birth
  • had gestational diabetes in a previous pregnancy
  • PCOS (poly cystic ovarian syndrome)
  • a family history of diabetes – one of your parents or siblings has diabetes
  • your family origins are South Asian, black Caribbean or Middle Eastern
  • aged 35 or older

Gestational diabetes means that the mother cannot produce enough insulin, or cannot utilise insulin well enough to process the glucose in the bloodstream and blood sugar levels remain too high.

Gestational diabetes lasts for the duration of the pregnancy and then blood sugar levels return to normal. In some cases, where blood sugar levels do not return to normal, this means that the woman was diabetic previous to pregnancy but the diabetes was not diagnosed.

Gestational diabetes diagnosis can be a daunting, scary and worrying time and so it important to have a good support network around you.

Why is gestational diabetes diagnosis important?

Having gestational diabetes means that a mother’s blood sugar levels remain too high. This means that excess glucose is passed through to the growing baby and can lead to complications for both the baby and for the mother when giving birth.

Being diagnosed means that blood sugar levels can be monitored, lowered and reduce related risks

Complications caused by gestational diabetes are:

  • Macrosomia– your baby being large for its gestational age e. weighing more than 4kg (8.8lbs) Macrosomia increases the need for induced labour or a caesarean birth, and may lead to birth problems such as shoulder dystocia
  • Shoulder dystocia – This is when your baby’s head passes through your vagina, but your baby’s shoulder gets stuck behind your pelvic bone. Shoulder dystocia can be dangerous, as your baby may not be able to breathe while they are stuck. It’s estimated to affect 1 in 200 births. Following shoulder dystocia deliveries, 20% of babies will suffer some sort of injury, either temporary or permanent. The most common of these injuries are damage to the brachial plexus nerves, fractured bones, contusions and lacerations, and birth asphyxia.
  • Premature birth(your baby being born before week 37 of the pregnancy) – This can lead to complications such as newborn jaundice or respiratory distress syndrome (RDS).
  • Polyhydramnios– Excessive amniotic fluid
  • IUGR– Intrauterine growth restriction is a condition where a baby’s growth slows or ceases when it is in the uterus
  • Pre-eclampsia
  • Health problems shortly after birth that require hospital care– such as newborn hypoglycaemia (low blood sugar) and/or newborn jaundice
  • Stillbirth– *It should be noted that whilst this is a complication of gestational diabetes, this is seen in cases where GD is not diagnosed or blood sugar levels are not monitored and/or controlled

Screening of gestational diabetes

Unfortunately, not all pregnant women are routinely screened for gestational diabetes in the UK.

Women who have increased risk factors are usually screened with an oral glucose tolerance test (OGTT), or oral glucose challenge at around 24-28 weeks of pregnancy.

During routine midwife appointments, if high glucose levels are found in urine samples, the midwife may refer women for an OGTT, or an earlier test for those who are in the higher risk groups.

What is an oral glucose tolerance test (OGTT)?

The OGTT is test used to diagnose gestational diabetes in the UK. This test may be performed at a GP surgery, or at a hospital clinic and takes place first thing in the morning.

The mother is asked to fast overnight (not eat for 10-12 hours previous), have a blood test upon arrival, drink a specific measured amount of sugary drink and a further blood test is taken after 2 hours (and in some cases after 1 hour too).

GD UK TIP: OGTT take a long time and so it is best to take something to read and childcare if possible to avoid long boring waits at the clinic with young children. It is also worth packing a snack in your bag for after the test is complete.

What happens next?

If you are diagnosed with gestational diabetes, your midwife or clinic should call you, or send a letter of notification with a copy of your OGTT results.

You will be asked to attend an appointment where you should be given a blood glucose testing monitor and a diary for recording your test results. You will also be given test times and blood sugar level targets.

You will also receive appointments to meet with the diabetes team and a dietician.

From this point onwards, you may need to modify your diet and will need to test your blood sugar levels multiple times a day, keeping a record of the results.

You will be asked to attend regular hospital appointments to see how you are getting on with monitoring the gestational diabetes and should receive additional ultrasound growth scans on the baby.

Gestational diabetes diet and exercise

The majority of glucose in the bloodstream comes from the food and drink. This means that making changes to diet can have a major positive impact on lowering and stabilising blood sugar levels.

Reducing or eliminating sugar, sweets, cakes and full sugar drinks alone is not enough to lower blood sugar levels significantly with gestational diabetes.

Carbohydrates turn into glucose in the bloodstream which means reducing the amount eaten and choosing better carbs which take longer to be processed in the body.

A real food diet of unprocessed foods which are high in protein, high in good natural fats, with plenty of leafy green vegetables and salad, with small servings of complex carbohydrates have the best results for helping maintain good blood sugar levels.

To help explain the GD diet, we have 8 Golden Rules to follow: –

  1. Eat little & often – ideally 3 meals and 3 snacks a day
  2. ‘Pair’ foods so that they will be tolerated better – “food pairing” is a term used which means eating carbs alongside protein and good fats. This slows down the release of glucose into the bloodstream
  3. Eat high protein – plenty of meat, fish, eggs, nuts, seeds, pulses, tofu and Quorn
  4. Eat good, natural fats – good amounts of nuts, seeds, olives, avocado, oily fish, coconut oil and full fat dairy products
  5. Eat small amounts of unrefined complex starchy carbohydrates at every meal – stick to one starchy carb per meal e.g. 3 tbsp of wholegrain rice, whole wheat pasta, wholegrain couscous, 3 egg sized new potatoes, 1 small jacket or sweet potato, 1 x 800g or 2 x 400g loaf slice of high protein bread, 3 x wholegrain crackerbread, 4 x Scottish oatcakes
  6. Bulk up meals with lots of green vegetables & salad – fruit contains a lot of natural sugars, so eating plenty of less starchy, green vegetables is the best way to ensure the diet remains rich in fibre, vitamins and minerals
  7. Drink plenty of waterwater helps to flush sugar through the body, therefore lowering blood sugar levels
  8. Go for a stroll –   exercise has an insulin type effect on the body, so exercising, even if only walking after eating is extremely beneficial


For some women, dietary changes are not enough to lower blood sugar levels significantly enough. In these cases, medication can be given which will help alongside following a good diet.

An oral medication called Metformin is usually the first line of medication used in treating high blood sugar levels with gestational diabetes. Metformin is a tablet which aids the body in utilising insulin better. The most common side effect of Metformin is gastric upsets. Metformin side effects are lessened if the tablets are taken midway through meals. There is also a modified release version which may be better suited to those that have other gastric complaints such as IBS. Metformin tablets are quite large, but Metformin is also available as a liquid.

Metformin does cross the placenta but has been deemed as safe to use during gestational diabetes pregnancies following major research trials.

If Metformin is not enough to lower blood sugar levels, or if the mother cannot take Metformin, the next line of treatment is insulin therapy.

Insulin is a direct top of the body’s own insulin and is a liquid which needs to be injected.

Insulin injections may seem daunting but the insulin comes in a prefilled pen type device where the dose is selected by turning a dial (rather than a needle and syringe), which makes injecting much easier. The needle used is very small and injections hurt less than the finger prick testing of blood sugar levels.

Insulin comes in 2 different forms. Bolus insulin is rapid acting insulin which is taken before or after eating to control the blood sugar level rise after eating. Basal insulin is slow releasing background insulin which may be taken before bed and/or in the morning. Bolus or basal insulin will be given depending on where insulin control is needed and in many cases both bolus and basal insulin may be used. Insulin does not cross the placenta and is safe for use in pregnancy.

The diabetes team will advise when to take your insulin and what dose to take. This will be reviewed regularly and doses adjusted as needed.

Beware 32 – 36 weeks, the toughest time!

The insulin resistance in gestational diabetes is driven by hormones. At around 26 weeks, large amounts of cortisol are released and cortisol is a hormone which causes high insulin resistance, meaning there is a raise in blood glucose levels, hence gestational diabetes is typically diagnosed between 24 – 28 weeks. (If you were diagnosed earlier than 26 weeks, you may see a big raise in insulin resistance at around this time).

At around 32 weeks there is a raise in progesterone hormone levels and insulin resistance can crank up to another gear! It’s at around this point that we typically see insulin resistance worsen for mothers with GD.

For many, this peak in insulin resistance then settles slightly after around 36 weeks.

Colostrum Harvesting

One of the biggest complications seen in babies born to diabetic mothers is low blood sugar levels following birth. This is due to the baby having to overproduce insulin when processing the excess blood sugars fed from the mother, then once born they struggle to regulate insulin production.

Low blood sugar levels at birth can lead to neonatal hypoglycaemia. The best way to treat low blood sugar levels is lots of skin to skin and feeding.

Babies born to diabetic mothers can often be quite sleepy and may have difficulty feeding. If there are any problems feeding, or where breast feeding alone is not enough, then top up feeds will be given.

If colostrum (the first breast milk) is not available, then formula top ups will be given.

If colostrum has been expressed and collected, then colostrum top ups can be given instead of formula.

Colostrum harvesting is the process of expressing, collecting and storing colostrum in preparation for the birth of the baby.

It is safe to hand express colostrum from 36 weeks onwards. Harvested colostrum can be stored in syringes and frozen. Each syringe must be labelled clearly and can be defrosted for use as and when necessary. It is advisable to use 1ml-2ml syringes so that small amounts can be given and no colostrum is wasted.

It is advisable to check what facilities are available at your hospital for storing frozen colostrum during your birth. If facilities are not available, then a cool bag with freezer blocks works well!

Placenta insufficiency – things to watch out for!

Placental structure and function can be changed as a result of maternal diabetes, therefore having gestational diabetes means that you are at a higher risk of having placenta issues. Watch for the following symptoms: –

  1. Changes in baby’s movements– always get changes (decreases and/or increases) in baby’s movements checked
  2. A sudden drop in blood sugar levels– levels dropping much lower than usual for you to very low levels (2.0’s – 3.0’s mmol/L) consistently can be a sign that there are issues with the function of the placenta. It is best to consult a medical professional if you see a drop in levels like this.
  3. Frequent hypos in insulin controlled mothers– frequent hypos with lack of ability to raise blood sugar levels following hypo treatment and a need to dramatically decrease insulin therapy should be called in to a medical professional for advice.
  4. Levels not raising after eating– levels which are not raising after eating typical meals can suggest there are issues with the placenta function and so you should call your diabetes team to discuss this.
  5. Lack of or slowed growth of baby– baby’s which have slowed growth may be at risk of placental issues. This is detected during an ultrasound growth scan and your medical professionals will discuss with you the best plan of care.

Birth and how having gestational diabetes may impact your birth plans

Having gestational diabetes may mean you are advised differently to that of a woman with a low risk pregnancy regarding birth.

It means that there may be risks of complications which require the baby to be delivered at an earlier gestation and in a place where there is suitable facilities and professionals to assist if necessary, under consultant-led care.

Just because you have been diagnosed with gestational diabetes does not mean all your birth plans have to be thrown out of the window.

The timing and mode of birth should be discussed with your diabetes team and a plan should be reached together.

The NICE guidelines recommend that women with gestational diabetes should be advised to give birth no later than 40+6 weeks, but to consider elective birth before 40+6 weeks for women with gestational diabetes if there are maternal or fetal complications.

Blood sugar levels will need to be monitored throughout the labour until birth and if levels do not stay within 4.0mmol/L – 7.0mmol/L the use of a variable rate intravenous insulin infusion (or ‘sliding scale’) may be used to help maintain stable blood sugar levels.

Having a gestational diabetes birth means understanding what risks are associated, how those risks may or may not apply to you and being able to make an informed decision on what you feel is the best thing to do.

After the baby is born

Once the baby is born, daily monitoring of the mother’s blood sugar levels is no longer required and any medications for lowering blood sugar levels can be stopped.

In the majority of hospitals, additional to the routine newborn checks, babies born to diabetic mothers are usually monitored for hypoglycaemia (low blood sugar levels). Each hospital is different as to how they monitor the blood sugar levels, but the procedure is the same.

A midwife or nurse will heel prick the baby to obtain enough blood to be tested on a blood glucose test monitor, the same as used to monitor our own blood sugar levels throughout pregnancy.

The number of tests taken can vary and the times taken, but your hospital will have a policy which they will follow.

If the baby’s blood sugar levels are too low, then top up feeds will be given to help raise levels. If this does not raise levels sufficiently then glucose solution or gel may be given, or if there is a greater concern, they may need to be given an intravenous fusion of glucose.

Being tested for diabetes following birth

After giving birth, in the majority of cases, blood sugar levels will return to normal (however it should be noted that it can take a while for hormones to settle and so this may take a few weeks). If levels do not return to normal it can indicate that the mother has Type 1 or Type 2 diabetes.

At 6 weeks post-partum the mother should be tested for diabetes by having a fasting blood test, or a HbA1c blood test at 13 weeks. A HbA1c blood test requires no fasting and is one simple blood test that can be taken at any time of day. It shows an average of blood glucose levels over a 3-month period.

The HbA1c may be more beneficial to new mothers, especially if breastfeeding as there is no need to fast for this test.

Annual diabetes testing and lifestyle modifications

Gestational diabetes increases the risk of developing type 2 diabetes later in life. Statistics from Diabetes UK state that there is a seven-fold increased risk in women with gestational diabetes developing type 2 diabetes in later life. NICE state that up to 50% of women diagnosed with gestational diabetes develop Type 2 diabetes within 5 years of the birth. This risk increases if you gain weight too, for every 1kg gain over the pre-pregnancy weight there is a 40% increased risk of developing Type 2 diabetes.

For this reason, it is important to be tested annually for Type 2 diabetes with either a fasting glucose blood test or HbA1c blood test.

Things which can reduce the risk of Type 2 diabetes are: –

  • Breastfeeding
  • Lose weight (if you have weight to lose)
  • Exercise

Making good choices for our family – future risks

Children born to mothers with diabetes during pregnancy tend to have a greater BMI, raised fasting glucose levels and an increased risk of developing Type 2 diabetes later in life. The latest research suggests they have a six-fold increased risk of developing Type 2.

As mothers who have had gestational diabetes we will have learned so much about diet and nutrition. What helps obesity? Diet and exercise. What helps prevent and reverse symptoms of type 2 diabetes? Diet and exercise.

By using the knowledge we learn through our pregnancies, we have the power to make a difference!

If you fall pregnant again, you have an increased risk of developing gestational diabetes again.

By Joanne Paterson, Gestational Diabetes UK

Important resources:


Giving Birth: What To Pack In Your Hospital Bag

Five Different Baby Positions in The Womb & What They Mean

For competitions and offers from our favourite brands, click here.

In The Spotlight

Eaton Square Nursery Schools

At Eaton Square Nursery Schools, we offer a nurturing and stimulating environment for children aged 2 to 4 years old, with a rich and varied curriculum that encourages curiosity, creativity, and confidence. Our experienced and qualified staff are committed to supporting each child’s individual needs and interests. We have four nursery classrooms in two locations: Eccleston Square and Lupus Street. Eaton Square Nursery Schools children enjoy the benefit of priority admission to Eaton Square Prep School.



Latest posts

Living / 18 April, 2024

Autism-Friendly Family Travel: Tips For A Stress-Free Journey

Activities & Days Out / 18 April, 2024

8 Spring Activities To Get The Family Outdoors

My Baba Measure / 17 April, 2024

The Measure: What’s Hot For Parents & Kids

Parenting / 17 April, 2024

Letting Go Of The Dummy: Timing And Tactics For Transitioning Away

Expert / 16 April, 2024

Empowering Parenthood: How Community Pharmacists Offer Support And Guidance