Gestational diabetes is a medical condition-that occurs during pregnancy. Its prevalence is increasing, mainly due to higher rates of obesity and changes in lifestyle patterns. Next, we will analyze how this condition occurs, its implications for health, how to prevent it, and its treatment.
What is gestational diabetes?
Gestational diabetes, also called gestational diabetes mellitus (GDM), is a medical condition and a growing health problem that usually occurs during the second half of pregnancy.1. When a woman develops GDM, her blood glucose (sugar) levels are higher. Generally, the hormone insulin reduces the amount of glucose in the blood, for example, by helping glucose access muscle cells, liver, and adipose tissue. During pregnancy, the need for insulin is greater, but hormonal changes can reduce the responsiveness of cells to it. Under normal conditions, when blood glucose levels rise, the pancreas secretes more insulin. However, when the pancreas cannot generate enough insulin the control blood glucose levels, a “glucose intolerance” develops, which, if it occurs during pregnancy, is called GDM.
Medical implications
GDM can have medical consequences for mother and baby. Glucose crosses the placenta and causes an overgrowth of the fetus. Macrosomia is a medical condition according to which babies are too large for their gestational age, i.e., between 4 kg and 4.5 kg of birth weight, which can lead to complications in childbirth, such as shoulder dystocia (the baby’s shoulders get stuck behind the pubic bone during delivery) and perinatal morbidity.2. GDM is also associated-with an increased risk of preeclampsia which, if left untreated, can be fatal.3.
Mothers with GDM have an increased risk of developing diabetes later in life. Although diabetes usually goes away after birth, more than 50% of women who have had GDM will-develop type 2 diabetes within 5 to 10 years of delivery.4. In addition, children of women with GDM also have an increased risk of developing overweight, obesity, and type 2 diabetes during their lifetime.4. When these complications are identified early, the risks involved can be reduced by specific lifestyle changes.
Prevalence and risk factors
The prevalence of GDM varies between different European populations, ranging from 1.7% to 11.6%, with higher rates in the south than in northern and central Europe.5.
The following factors may increase a woman’s risk of developing GDM6,7:
- a body mass index-greater than 30 kg/m2 (obesity),
- previous pregnancy with GDM or microsomal baby,
- a first-degree relative with diabetes,
- membership of certain ethnicities, e.g., South Asia, black people of Caribbean origin, or the Middle East6,7.
Diagnosis
Screening for GDM is not carried out consistently across Europe. The World Health Organization (WHO) recommends an oral glucose tolerance test at 24-28 weeks gestation for women with risk factors for gestational diabetes (or random or abnormal fasting plasma glucose levels)8. This oral test tests your blood for fasting glucose and then two hours after drinking a glucose drink containing 75 grams of glucose.
Recently the WHO has recommended basing the diagnosis of GDM on the following values3:
- fasting plasma glucose levels between 5.1 and 6.9 mmol/l,
- 1 hour after a glucose load of 75 grams, the plasma glucose level is ≥10 mmol/l,
- 2 hours after a glucose load of 75 grams, the plasma glucose level is between 8.5 and 11 mmol/l.
Prevention and treatment strategies
There are several “modifiable risk factors” (those that can be controlled) that can help reduce the risk of GDM, such as having a healthy body weight before becoming pregnant, being physically active, and following a healthy, balanced diet that includes plenty of whole grains, fat-free protein, oily fish, and monounsaturated and polyunsaturated fats in a balanced way.7,9. Intake of foods and beverages with a high glycemic index (GI) should be minimized.
Once an oral glucose tolerance test has confirmed GDM, the first treatment strategy should be a referral to a dietitian-nutritionist. Although dietary changes and exercise can help improve the condition, it is estimated that 70% of women will require additional treatment such as oral hypoglycemics or insulin injections.7. Women with GDM usually receive advice from healthcare professionals to control their blood sugar levels themselves.