Complications of gestational diabetes
Is my baby at risk of complications now I have gestational diabetes?
Gestational diabetes is a serious condition which can cause many complications. The advice given by your diabetes health care professionals should be taken seriously as uncontrolled or poorly controlled gestational diabetes can lead to severe complications. Having gestational diabetes itself automatically causes higher risk of certain complications during pregnancy, although the risk of complications is greatly reduced if gestational diabetes is diagnosed and managed properly throughout your pregnancy.
Gestational diabetes only causes bigger babies - expelling the myth!
The most well known complication and general cause of concern of gestational diabetes is 'large babies' - the excessive growth caused by excess sugars in the mother's bloodstream. HOWEVER, if gestational diabetes is controlled and managed well, babies are rarely born 'big', but they may suffer other complications which are related to the condition. We often hear new members of our support group say that they are not worried as baby isn't measuring big, but monitoring for other complications which gestational diabetes can cause or be related to is extremely important.
Unfortunately there are many more complications which can be related to gestational diabetes and poor glucose control than 'just a big baby'.
If you have family and friends that are struggling to understand gestational diabetes, then you may want to refer them to this page and our page on gestational diabetes and the family to have a look.
Possible complications if blood glucose levels are not controlled or poorly controlled
If gestational diabetes is not managed properly, or goes undetected/undiagnosed, it could cause a range of serious complications for both you and your baby:
- Macrosomia - your baby being large for its gestational age i.e. weighing more than 4kg (8.8lbs) This is the most commonly known complication of gestational diabetes. Macrosomia increases the need for induced labour or a caesarean birth, and may lead to birth problems such as shoulder dystocia (see below)
- Shoulder dystocia - Macrosomia can lead to a condition called 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).
- Health problems shortly after birth that require hospital care – such as newborn hypoglycaemia (low blood sugar) and/or newborn jaundice
- Miscarriage – the loss of a pregnancy during the first 23 weeks
- Stillbirth – the death of your baby around the time of the birth
Other complications related to gestational diabetes
- Placenta insufficiency - premature ageing of the placenta, also known as placenta deterioration, placenta dysfunction or placenta failure. A direct complication linked to gestational diabetes which causes abnormalities and complications in the placenta. For further information on placenta deterioration, read more here. NOTE: Consult your diabetes health care professionals should you start experiencing frequent, very low blood sugar levels and/or frequent hypos. It is important to get checked and monitored if a difference in baby's movements are noticed; please call your maternity assessment unit immediately.
- Polyhydramnios - Excessive amniotic fluid - detected by ultrasound. Polyhydramnios can be caused by polyuria (frequent urination) and lung liquid production. Detection of polyhydramnios can be the flagstone for gestational diabetes testing in mother's who have not yet been diagnosed.
- IUGR - Intrauterine growth restriction is a condition where a baby's growth slows or ceases when it is in the uterus, also known as SGA or small for gestational age (under 10th centile for gestational age) - detected by ultrasound. A shock to many as it's contradictory to the usual complication of macrosomic (large for gestational age) baby.
- Pre eclampsia - Pre-eclampsia is a condition that affects some pregnant women, usually during the second half of pregnancy (from around 20 weeks) or soon after their baby is delivered. Early signs of pre-eclampsia include having high blood pressure (hypertension) and protein in your urine (proteinuria). It is unlikely you will notice these signs, but they should be picked up during your routine antenatal appointments. In some cases, further symptoms can develop, including:
- swelling of the feet, ankles, face and hands caused by fluid retention (oedema)
- severe headache
- vision problems
- pain just below the ribs
If you experience any of these symptoms of placenta deterioration or pre-eclampsia, then please seek medical advice immediately
*Please note: this is not an exhaustive list of possible complications related to gestational diabetes
The most common complications
Even in mothers who have maintained good control of blood sugar levels throughout pregnancy, the most common complications are:
- Health problems shortly after birth that require hospital care
- newborn hypoglycaemia (low blood sugar) and/or
- newborn jaundice
Most commonly seen complications seen in our Facebook support group
The most commonly seen complications in gestational diabetes babies we've had in the group have been neonatal hypoglycaemia and neonatal jaundice. Placenta deterioration, Polyhydramnios and IUGR have also been seen in the group a few times and has led to ladies being induced or delivered earlier than previously planned.
Neonatal or newborn hypoglycaemia
Newborn babies of diabetic mothers when there has been poor diabetic control in pregnancy will often struggle with their own blood sugar levels after birth. This is due to them overproducing their own insulin whilst growing in the uterus, in a way to help process the excess sugars passed from the mothers bloodstream. These babies may have high insulin levels persisting in the first few days after birth which can result in hypoglycaemia. Babies of mothers who have had reasonably good blood glucose control may still suffer with low blood sugar levels after birth too.
Testing the newborn for hypoglycaemia
In the majority of hospitals, newborns born to diabetic mothers are monitored for hypoglycaemia. 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 we use to monitor our own blood sugar levels throughout the pregnancy. You may find watching this distressing as sometimes (but not always) baby may become distressed, screaming and crying once they have been pricked with the lancet. You may notice that your baby's foot looks blue or purple in colour following the testing too. As much as this may seem terrible for your baby to go through, it is very important that levels are checked to make sure they are not suffering hypoglycaemia.
The amount of tests taken can vary and the times taken, but your hospital will have a policy which they will follow. The most commonly used test times are 3 tests, 3 hours apart either before or after feeding which must all be above a certain target. Once again, different targets are used for this. Some hospitals may have longer testing times such as 3 hourly for 24 hours and we have seen a couple of our Mums in the Facebook support group inform us that they do not test babies for hypoglycaemia in their hospital. Our advice would be to enquire about this and raise concerns should you have any. NICE guidelines recommend in their 'Preventing and assessing neonatal hypoglycaemia' guideline that
1.5.7 All maternity units should have a written policy for the prevention, detection and management of hypoglycaemia in babies of women with diabetes. 
- Keep blood sugar levels within target and stabilised - It is best try to keep your blood sugar levels within your targets and stabilised throughout your pregnancy, especially leading up to and during labour. Some mothers will be on a sliding scale insulin & glucose drip to control blood sugar levels during labour, but this may not be necessary if you gain good control over your levels.
- Skin to skin and 1st feed - Once baby is born, skin to skin is very important and initiating a first feed within the first 30 mins will aid good blood sugar levels in baby.
- Colostrum harvesting - Many mothers with gestational diabetes harvest colostrum before the birth of baby to be able to give the newborn top up feeds, should breast feeding be a problem, or to give additional top up feeds in between feeds as colostrum is the best thing to raise blood sugar levels.
NICE guidelines regarding neonatal hypoglycaemia
Preventing and assessing neonatal hypoglycaemia
1.5.7 All maternity units should have a written policy for the prevention, detection and management of hypoglycaemia in babies of women with diabetes. 
1.5.8 Test the blood glucose of babies of women with diabetes using a quality‑assured method validated for neonatal use (ward‑based glucose electrode or laboratory analysis). 
1.5.9 Women with diabetes should feed their babies as soon as possible after birth (within 30 minutes) and then at frequent intervals (every 2–3 hours) until feeding maintains pre‑feed capillary plasma glucose levels at a minimum of 2.0 mmol/litre.[2008, amended 2015]
1.5.10 If capillary plasma glucose values are below 2.0 mmol/litre on 2 consecutive readings despite maximal support for feeding, if there are abnormal clinical signs or if the baby will not feed orally effectively, use additional measures such as tube feeding or intravenous dextrose. Only implement additional measures if one or more of these criteria are met. [2008, amended 2015]
1.5.11 Test blood glucose levels in babies of women with diabetes who present with clinical signs of hypoglycaemia, and treat those who are hypoglycaemic with intravenous dextrose as soon as possible. [2008, amended 2015]
Jaundice causes yellowing of the skin and the whites of the eyes. Jaundice is one of the most common conditions that can affect newborn babies.
Treatment of jaundice
Frequent feeding and exposing baby to natural light helps the jaundice. Treatment is usually only recommended if tests show a baby has very high levels of bilirubin in their blood because there is a small risk in these cases that the bilirubin could pass to the brain and cause brain damage. The main treatment that can be carried out in hospital to quickly reduce baby's bilirubin levels is phototherapy – a special type of light shines on the skin, which alters the bilirubin into a form that can be more easily broken down by the liver. Babies are put on a light bed also known as a 'bili-bed'. This can usually be done at your bedside so that your baby can stay with you, but in more severe cases or sometimes where mobile facilities are not available your baby may be moved to SCBU (Special Care Baby Unit) or NICU (Neonatal Intensive Care Unit) for more intensive phototherapy.
In extremely severe cases, an exchange transfusion may be needed – a transfusion where small amounts of baby's blood are removed and replaced with blood from a matching donor. NICE guideline recommendations for neonatal jaundice
Delayed cord clamping and jaundice
Delayed cord clamping has many benefits but it does increase risk of jaundice. We advise doing your research and weigh up the pros v's the cons to make an informed decision.
Here's Gemma's story. Gemma has had 4 GD pregnancies and is now on her 5th...
"All 4 of my babies have had jaundice. The first 3 had their cords clamped quickly and were treated with one phototherapy lamp on the ward with me.
My most recent GD baby (December 2014) had severe jaundice requiring extensive phototherapy in intensive care for 4 days, he was on the cusp of needing a transfusion and was still classed as jaundiced for weeks later.
He had to be on a tinfoil bed with a billi blanket under him & 4 sets of lights on highest intensity on top (shown above). He wasn't even allowed out to be fed as you can see. We had to establish breastfeeding later.
All the blood tests they need are horrible too - Every four hours. And that was all of my babies, the severe case and the more mild ones.
When they reviewed my notes with my 4th it was apparent that due to several factors in my labour there had been a delay in his cord being clamped by a few minutes (not by my request) and the consultants working closely with him suggested after reviewing my notes that the cause for his extreme levels were down to the delayed cord clamping.
Obviously it won't be the same in every case but that's my experience with 4 jaundice GD babies. Three with quick clamping, one delayed. I'll be making sure it's clamped straight away this time to reduce the risk"
Evidence based research on delayed cord clamping and jaundice:
significantly more infants (relative risk 0.59; 95% CI 0.38–0.92) in the late cord clamping and cutting group required phototherapy for jaundice than in the early cord clamping and cutting group (five trials, 1762 infants). These results were influenced by a large unpublished trial (McDonald 1996, PhD thesis) in which late cord clamping and cutting was done when cord pulsation had ceased or at 5 minutes if cord pulsation had not ceased.
The authors of a meta-analysis of 1762 infants concluded a significantly higher rates of phototherapy (RR, 1.69; 95% CI, 1.08 to 2.63) and clinical jaundice  in infants in the delayed cord clamping group
In addition, there does not appear to be any difference between infants receiving early versus delayed cord clamping with respect to immediate birth outcomes, such as Apgar scores, umbilical cord pH, or respiratory distress. Although maternal outcomes have not been rigorously studied, the incidence of postpartum hemorrhage is reported to be similar between immediate and late cord clamping groups.
There is evidence, however, to support delayed cord clamping in preterm infants. As with term infants, delaying cord clamping 30–60 seconds after birth with the baby at a level below the placenta is associated with neonatal benefits, including improved transitional circulation, better establishment of red cell volume, and decreased need for blood transfusion. The single most important clinical benefit for preterm infants is the possibility for a nearly 50% reduction in intraventricular hemorrhage. It is also important to note that the timing of umbilical cord clamping should not be altered for the purpose of collecting cord blood for banking .
Breathing difficulties and RDS (respiratory distress syndrome)
If your baby is due to be delivered before 38 weeks gestation by induction or possibly later by elective caesarean section, then you may be advised to have steroid injections to mature your baby's lungs which helps prevent breathing difficulties. Steroids cause high blood sugar levels and so some hospitals will admit you if you need steroid injections. To help regulate blood sugar levels following steroid injections a sliding scale (insulin & glucose drip) may be used. Some hospitals however, will not admit you for steroid injections but will advise you call in if your levels go over a certain level. This differs depending on the area and NHS Trust.
If you have high blood sugar levels following steroid injections then you should contact your diabetic team or Maternity Assessment Unit. Drinking water helps to flush out excess sugars and walking helps to lower blood sugar levels, but this may not make as much of an impact as it usually does following steroids. It is important to seek medical advice if your blood sugar levels remain high.
For more information on the sliding scale insulin and glucose drips, please read more here.
Sliding scale (insulin & glucose)
Sliding scale is an IV drip with glucose and insulin (2 drips). It helps to stabilise blood glucose levels by adding glucose if your levels drop too low and adding insulin if your levels raise too high. They are commonly given to ladies who need steroid injections for inductions and planned c-sections before 38 weeks. Steroid injections are used for lung maturity as respiratory problems are higher risk with premature babies, those delivered by CS and babies born to mothers with gestational diabetes and the injections can cause very high blood sugar levels. Not all hospitals admit or use a sliding scale whilst giving steroid injections.
The other time sliding scales are used are during labour for some ladies with diabetes. Some hospitals will use them as per their Trust or hospital policy; diet, metformin or insulin control makes no difference. Other hospitals will only use them for insulin controlled mothers and some will only use them if they see blood sugar levels drop or spike to a certain level. If you have stable well controlled blood sugar levels throughout pregnancy and labour, then a sliding scale is not necessary.
Caesarean section due to gestational diabetes
Gestational diabetes in itself as a condition is not a reason to be advised to have a caesarean section. However planned caesarean may be offered to you, or advised if your baby is showing very large for gestational age following growth scans, where diagnosis has been very late in the pregnancy or where poor glucose control has been an issue.
Induction of labour
For many ladies with gestational diabetes, due to many of complications mentioned above, we may be advised to be induced due medical reasons. According to the current NICE guidelines induction (or elective caesarean section) should only be considered before 40+6 weeks for women with gestational diabetes if there are maternal or fetal complications. For more information on Induction of labour please read more here.
Post birth diabetes testing
Gestational diabetes increases your risk of developing type 2 diabetes after the pregnancy. Statistics from Diabetes UK state that there is a sevenfold 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.
It is recommended that you should have a fasting glucose blood test at 6 weeks post-partum OR a HbA1c blood test after 13 weeks post-partum to check that you are clear of diabetes. It is no longer recommended that a repeat GTT is performed to check that the diabetes is clear (NICE guidelines Feb 2015). Many ladies have concerns over taking a fasting glucose test whilst breast feeding, or attending for blood tests whilst their newborn is still very young. If you have these concerns then you may want to opt for a HbA1c blood test after 13 weeks post-partum. You do not need to fast and it is one simple blood test that can be taken at your local GP surgery.
It is important to be tested annually for diabetes following gestational diabetes with a HbA1c blood test. Type 2 diabetes is when your body either does not produce enough insulin, or the body’s cells do not react to the insulin causing insulin resistance.
Knowing the risk factor of being diagnosed with type 2 diabetes later in life is higher, it is advisable to look and dietary and lifestyle choices which could impact and lessen your chances of being diagnosed.
We very rarely see ladies being diagnosed as type 1 diabetics following gestational diabetes, but gestational diabetes may be the flagstone for testing for type 1 diabetes.
For further information on post birth diabetes testing, please read more here.
Complications later in life for your baby
Your baby has a sixfold increase in risk of developing diabetes and has a higher risk of obesity (having a body mass index of more than 30) later in life.
After having gestational diabetes, you are at increased risk of having gestational diabetes in any future pregnancies. It's very important to speak to your GP if you are planning another pregnancy or when you fall pregnant. They may arrange for you to monitor your own blood glucose from the early stages. Some hospitals will assume that you have gestational diabetes in a subsequent pregnancy and will treat you as such from the start. Other hospitals will get you to perform an earlier GTT (glucose tolerance test), this is commonly around 16 weeks. Following a negative GTT, repeat GTT is usually offered.
Treating GDM reduces risk for many important adverse pregnancy outcomes and its association with any harm seems unlikely.
Treatment of gestational diabetes reduces serious perinatal morbidity and may also improve the woman's health-related quality of life.
Women with pre-gestational (type I and type II) diabetes mellitus (DM) have an increased risk of second and third trimester stillbirth compared to women without diabetes. Even with modern obstetric care and diabetes management, stillbirth rates in women with type II DM have been reported to be 2.5-fold higher than non-diabetic women . On a population-basis, women with gestational diabetes (GDM) have similar stillbirth rates as a normal population. However, some women with “GDM” diagnosed during pregnancy actually entered the pregnancy with undiagnosed type II DM, and have the same risk of fetal loss as women with type II DM. Thus, when there is clinical evidence that a woman with GDM may have undiagnosed type II DM, she should be considered to be at increased risk of stillbirth. Examples of women who may have undiagnosed type II DM include those with high fasting glucose values, random or postprandial glucose values >200 mg/dl, history of GDM in prior pregnancies (particularly when no glucose testing was done in the interval between pregnancies), or diagnosis of GDM early in pregnancy.
The factors that account for the increased risk of late pregnancy fetal loss in diabetic women are not fully understood. Although an increased likelihood of fetal anomalies contributes to the increased risk, the stillbirth rate for non-anomalous fetuses is also higher in diabetic women than in non-diabetics. Co-morbid conditions, such as obesity and hypertension, are also more common in women with DM. Fetal growth abnormalities, both growth restriction and excessive growth, are increased in women with DM, and both increase the risk of stillbirth. The link between excessive fetal growth and stillbirth likely involves maternal hyperglycemia leading to fetal hyperglycemia, which in turn triggers excess fetal insulin production to keep fetal plasma glucose levels in the physiologic range. In the fetus, insulin spurs fetal growth, which may result in metabolic acidosis if excessive, and if the placental oxygen supply is insufficient. The endpoint of this process may be a stillbirth.
The exact glycemic threshold that places a diabetic pregnancy at increased risk for stillbirth is not well characterized. However, it has been shown that identifying and treating diabetes lowers the stillbirth rate in these women .
We conclude that identification and treatment of women with gestational diabetes can reduce perinatal mortality rates.