Its full name is Gestational Diabetes Mellitus (GDM). It's a condition that affects around 8% of pregnant women and is usually temporary during pregnancy, but it can lead to increased chance of developing type 2 diabetes later in life.
In simple terms the placenta produces hormones that interfere with how effectively insulin and insulin receptors work in the body to process sugar. At the same time your need for insulin is 2-3 times greater than pre-pregnancy.
Insulin performs the important role of transporting glucose out of your blood and into your muscles and liver for use or storage. When it is not working effectively, the glucose builds up in your blood and leads to high blood sugar levels which are unhealthy and which mean your baby gets too much sugar.
The main challenges if the GDM is not managed effectively are having a baby that is loo large at birth which can result in a planned or emergency caesarean or for the baby's shoulder (actually clavicle) to need to be broken during the birthing process (double ouch!) Immediately after birth baby also risks having dangerously low blood sugar levels as the sugar is effectively switched off as soon as the cord is cut.
So it's pretty serious and important to manage.
There are no real signs or symptoms that you have GDM, so screening is vital. I now know of many fit, healthy women who would never have expected to have GDM to be diagnosed with it as the effect of the hormones from the placenta interferes with the normal processes, even for those that are active and eat well.
Screening to identify GDM is done between 24-28 weeks with a blood test taken one hour after having a sugary drink. The test looks at how well your body has processed the sugar and if the blood sugar levels are high this leads you onto a second two hour test which is done after having a high carb diet for several days and then fasting overnight. Again blood sugar levels are tested but this time before during and after a two hour period of having yet another sugary drink. The drink actually which makes you feel quite queasy and is the complete opposite to what you want to do with your blood sugar levels if diabetic, but it is a means to an end to get the diagnosis.
Initially after diagnosis, women will have diet and exercise recommendations and will monitor their blood sugar levels four times a day to check that they can keep them within a safe range.
Over time it can become increasingly difficult to keep the blood sugar levels down, and if you reach a point where you are doing all that you can in terms of diet and exercise but are still exceeding the limits, the dieticians will then recommend injecting insulin to help the body out.
This ensures that both the mother and baby are safe and that baby does not get too large. It also helps prevent the likelihood of mother or baby developing type 2 diabetes later on.