What is gestational diabetes?
Gestational diabetes is defined as glucose intolerance that occurs in pregnancy. However, these may be instances where the diabetes existed prior to pregnancy and was undiagnosed. Nevertheless it is still considered as gestational diabetes unless it can be conclusively proven that it existed before a woman fell pregnant. Unlike type 1 and type 2 diabetes mellitus, gestational diabetes is not always a permanent condition. However, women who develop gestational diabetes have a 50% chances of developing type 2 diabetes up to 20 years after the diagnosis of gestational diabetes.
The raised glucose and insulin levels affects the fetus as well as the mother. However, it often does not present with any symptoms and a pregnant women who does not undergo routine screening may not be aware of the presence of gestational diabetes. There are health risks some of which can be permanent for the fetus if the glucose levels are excessively high and there is no medical intervention. Gestational diabetes mellitus (GDM) occurs in 14% of all pregnancies in the United States and is the most common metabolic complication of pregnancy. It can be effectively managed with diet and exercise but sometimes medication including insulin injections may be necessary.
Causes of Diabetes in Pregnancy
Diabetes mellitus, type 1 and 2 as well as gestational, is a condition where the blood glucose levels are raised because of the deficiency of insulin or the body’s impaired response to insulin. The pancreas secretes insulin when the blood glucose levels are raised. This lowers the blood glucose levels by increasing the uptake of glucose by cells. However, when insulin is lacking like in type 1 diabetes or the body does not respond to insulin (insulin resistance) as in type 2 and gestational diabetes then the blood glucose levels remain elevated (hyperglycemia).
Why doe gestational diabetes occur in some women?
The exact reason why gestational diabetes occurs is not known. There is a disturbance in insulin secretion during pregnancy in all women but this does not explain why some women will develop gestational diabetes and others do not. Placental hormones impair insulin response in all pregnancies particularly in the second half of the pregnancy.
However, the body counteracts it by increasing insulin production sometimes as much as 2.5 times the level as a non-diabetic woman who is not pregnant.In women who develop gestational diabetes the pancreas cannot cope by producing these higher than normal levels of insulin. As a result the blood glucose levels cannot be maintained within a normal range and gestational diabetes is diagnosed.
Gestational diabetes becoming more common
It has been observed that there has been a rise in the incidence of gestational diabetes in accordance with the rise in type 2 diabetes over the past two decades. It may be due to better diagnostic methods and widespread screening revealing the true incidence of gestational diabetes. However, gestational diabetes also appears to be associated with similar risk factors such as obesity and family history of diabetes. Given the current obesity epidemic, this may partly explain why gestational diabetes is becoming more common.
Which trimester does gestational diabetes start?
Gestational diabetes usually starts in the second half of the pregnancy. In other words it may occur in the latter half of the second trimester or even in the third trimester. However, it is possible for gestational diabetes to occur much earlier. It is unclear whether early diagnosis could at times be pre-existing diabetes mellitus even before conception.
Signs and Symptoms
Unlike with type 1 and type 2 diabetes mellitus, there are usually no noticeable symptoms with gestational diabetes for most women. The problem is that some of these symptoms of gestational diabetes when present is often attributed to pregnancy. Therefore routine screening is essential for all pregnant women usually around the 24th to 28th week of pregnancy and even earlier for high risk women.
However, pregnant women should be aware of the symptoms as it may present, particularly in untreated diabetes.
- Increased thirst which may sometimes be perceived as a dry mouth.
- Frequent urination which is often repeated urination of a full bladder.
- Urinary tract infections (UTIs) which are often recurrent.
It is important to know that the lack of symptoms does not mean that the raised blood glucose levels will not have an effect on both mother and baby. Also refer to lesser known facts about pregnancy diabetes.
Effects of Diabetes on Mother
The complications of diabetes in pregnancy may include:
- Preterm labor – birth may occur before 37 weeks.
- Preeclampsia – extremely high blood pressure (hypertension) during pregnancy.
- Excess amniotic fluid – increases risk of preterm labor.
- Difficult childbirth – baby is larger than normal.
Effects of Diabetes on Baby
The complications of diabetes on the baby includes:
- Macrosomia – the baby grows large than normal and there are risks to baby during childbirth.
- Hypoglycemia – baby may have low blood glucose levels after birth.
- Nenonatal jaundice – abnormal yellowing of the skin and eyes in babies shortly after birth.
- Obesity – higher risk of obesity later in life.
- Type 2 diabetes – higher risk of diabetes later in life.
Treatment of Diabetes in Pregnancy
Once diabetes is diagnosed in pregnancy, it should be continuously monitored and this monitoring will continue even after childbirth. Diabetic medication is usually not prescribed for every pregnant woman with gestational diabetes. Diet and lifestyle modification is first advised and it is effective for most women provided that it is carried out diligently.
- Diet: Should be formulated by a registered dietitian. A combination of a low glycemic index (GI) diet with plenty of fresh fruit, vegetables and whole grains.
- Exercise: Moderate exercise helps with insulin tolerance but has to be done regularly. An exercise program suitable for pregnant women should only be commenced with a doctor’s approval.
- Oral Medication: Drugs taken orally for gestational diabetes is not always advised. It is still unclear whether it is always safe for pregnant women and the fetus but is sometimes used.
- Insulin: It is administered with an injection and has the same effect as insulin that is naturally produced by the body. Insulin in pregnancy is usually reserved for severe gestational diabetes that is not responding to diet and exercise.