Gestational diabetes mellitus
While type 1 and type 2 diabetes are the two most prominent forms of diabetes there exists another, but perhaps a lesser well known form, that is termed gestational diabetes mellitus (GDM). In this blog we will talk about its causes, the developmental risk factors, the complications, and how the condition can be managed before, during, and after pregnancy.
What is gestational diabetes mellitus
As the name suggests, GDM is diabetes that develops during pregnancy. It is estimated to occur in approximately 16% of all pregnancies and typically presents during weeks 24-28 of the second trimester. More often than not, the condition resides after the birth of the baby. However, if left untreated during pregnancy, there are a number of complications that can occur.
During pregnancy, a temporary organ known as the placenta is developed in order to connect the mother to the foetus. This organ is connected to the baby via the umbilical cord and acts to supply the foetus with nutrients and oxygen for growth and development. In addition to supplying oxygen and nutrients, the placenta also produces a number of hormones that are used to support the pregnancy. However, some of the hormones produced have the negative effect of impairing the effectiveness of insulin in controlling blood glucose.
You may remember in one of our previous blogs, we discussed that insulin is produced within the pancreas and it is responsible for reducing blood sugar levels; whereby insulin acts like the key to open the locks on our cells to let glucose in to be used as energy.
As the pregnancy develops, so too does the size of the placenta. As a consequence of this increase in growth, the volume of hormones produced also increases. The result of which is the emergence of GDM.
The risk factors
Every pregnancy is at risk of the development of GDM. However there are a number of factors that increase this risk, such as:
- Entering the pregancy overweight or obese (BMI >30kg/m²)
- Having a family history of diabetes
- Having previously had GDM
- Having previously given birth to a larger baby (>9 pounds)
- Being of South Asian descent
- Being aged 25 and over at conception
If poorly managed during pregnancy, the elevated levels of energy from excessive blood glucose may cause the baby to grow too large. The result of which is that the mother may require a cesarean section to deliver the baby.
Moreover, complications can be experienced by the baby itself shortly after delivery. This can occur due to the baby's pancreas having to produce more insulin to manage the high levels of blood glucose that are received from the placenta. However, shortly after birth, the baby no longer receives a blood supply from the mother due to the umbilical cord being separated. As a result of this cut off, the high level of insulin being produced by the baby's pancreas may cause a sudden and dramatic drop in blood glucose levels of the baby. This drop in blood glucose results in what is termed hypoglycemia. One of the more serious consequences of hypoglycemia shortly after birth is that of the baby experiencing seizures.
Other complications that can be experienced include:
- Increased risk of hypertension for the mother
- Increased risk of diabetes after birth for the both the mother and baby
- Increased risk of premature birth
The risk of developing GDM for the most part can be reduced from losing weight before pregnancy and maintaining a healthy weight during pregnancy along with moderate physical activity. Research has shown that approximately 46% of all cases of GDM are attributed to having a BMI greater than 25kg/m².
We know that for those with diabetes who become pregnant, elevated levels of blood glucose during the first trimester pose a risk to the baby as the baby's vital organs are developing. Therefore it is vital that blood glucose levels are controlled prior to and during the pregnancy in order to provide the best opportunity for the baby's healthy development.
For those who develop the condition during pregnancy, simple dietary modifications up until the baby's birth can be all that is needed to effectively manage the condition. However, for approximately 30% of females who develop GDM, insulin therapy and close blood glucose level monitoring is required alongside dietary modifications.
After birth, the mother's blood glucose levels more often than not, return to normal. If elevated levels persist, this may be a sign that diabetes may have been present in the mother prior to conception.
The take home message
For the most part, GDM can be successfully monitored and managed thanks to the high levels of medical support that are provided to mothers from screening, to long after the birth of the baby. The biggest and most modifiable risk factors for GDM come from carrying excess weight and those with prediabetes.
From previous blogs, we know that blood glucose levels and the risk of developing type 2 diabetes can be improved with significant weight loss. By preemptively taking action on these risk factors, you can reduce the risk of GDM and the associated complications.
The Counterweight Fertility Programme provides expert 1:1 advice on factors that can affect fertility and how to make lifestyle changes for optimal fertility, pregnancy, and reproductive health.