What is a clinical study?
A clinical study is a type of medical research designed to look at a specific aspect of a disease or condition. The knowledge gained from the findings of the study can then be used for better diagnosis and management of other people with the same condition in the future.
What is Gestational Diabetes?
Gestational diabetes mellitus (GDM) is defined as diabetes which is first recognised during pregnancy. Pregnancy itself is an insulin resistant state (partially due to changes in the hormone levels of a woman’s body), which means that any underlying tendency for a woman to develop diabetes is increased during the time of pregnancy. Based on current information, around 5 to 15% of mothers develop GDM during pregnancy.
What can happen to mothers with GDM and their babies?
Although GDM is not common, it is an important problem that needs to be identified and managed well. The majority of mothers with GDM will have an entirely normal pregnancy, with no problems for themselves or their babies. However in a small group of mothers, having GDM (particularly if her blood sugar levels are not well-controlled) can result in giving birth to bigger babies with more fat stores at birth and certain complications at delivery (eg. higher rates of Caesarean section). There are also studies which have shown that these children can go on to have a higher risk of obesity and type 2 diabetes in childhood.
Mothers who receive a diagnosis of GDM during pregnancy are themselves at 7 to 8 times higher risk of developing Type 2 diabetes later on in life. Therefore, it is important to not only be closely monitored during the pregnancy but also afterwards (eg. through having a post-pregnancy glucose tolerance test and thereafterregular assessments by the GP).
Who is at high risk of GDM?
There are some mothers who are at higher risk of GDM – eg. those of older age, higher body weight, positive family history and from ethnic minority groups (eg. South Asians). However, these ‘traditional’ risk factors may only be present in around 60-70% of mothers who develop GDM so there may be other factors at play too. Some of these may be related to insufficiency of B12/folate levels in the blood, which is what we are planning to investigate in the PRiDE study.
How is GDM diagnosed/What is a Glucose Tolerance Test?
Currently, most hospitals in the UK carry out ‘selective screening’ to diagnose GDM, which means that only mothers with risk factors for GDM (such as increased body mass index, previous history of GDM or large baby, having a first degree relative with diabetes) are tested. However, if a mother has any other features to suggest possible GDM (eg. glucose in her urine, certain complications in the pregnancy), she may also be tested by her midwife/doctor.
The screening test to identify mothers with GDM is known as a Glucose Tolerance Test (GTT) and it is usually carried out between 24 to 28 weeks gestation. It involves the mother fasting overnight and taking a 75g sugary drink (such as Lucozade) in the morning. 2 to 3 blood tests are taken over the next 2 hours and if the glucose levels on any of these exceed a pre-determined cut-off, a diagnosis of GDM will be made.