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What is Gestational Diabetes?
Gestational diabetes is a condition which that develops in expecting mothers during pregnancy. It is characterized by high glucose (blood sugar) levels and occurs in approximately 4 to 8% of pregnancies.
Gestational diabetes does not often manifest symptoms, so your family medicine provider or OB will recommend that you get screened for high blood sugar levels around the 24th week of pregnancy.
These tests will often come back showing a higher than normal blood sugar reading, since nearly all women will have some degree of impaired glucose tolerance (also known as insulin resistance) during their pregnancy. This is a result of natural hormonal changes that occur while pregnant. However, most women, while having higher blood sugar than normal, do not have their levels rise beyond what is usual for pregnancy. For the few who do, they will be diagnosed with gestational diabetes.
What Causes Gestational Diabetes?
During pregnancy, certain hormones created in the placenta (the organ which connects the baby by the umbilical cord to the uterus) helps to transfer nutrients from the mother to the developing baby. These hormones help to prevent the mother from developing low blood sugar by resisting the action of insulin in the body.
Over the course of the pregnancy, these hormones will lead to progressive glucose intolerance which causes the blood sugar levels to spike higher than normal. In response, the mother’s body should naturally begin to produce larger quantities of insulin to force glucose into her cells to be used for energy. If the mother’s pancreas is able to keep up with the hormones produced, she will continue to have a normal pregnancy.
The problem occurs when the mother’s pancreas is unable to produce an adequate amount of insulin to compensate for the effect which the insulin blocking hormones are having on the mother’s blood sugar levels. If the pancreas is unable to keep up, the blood sugar levels will continue to rise and result in gestational diabetes.
Risk Factors for Developing Gestational Diabetes
Doctors have attributed the following factors as heightening the risk of developing gestational diabetes:
Being overweight prior to becoming pregnant (with a body mass index of 30 or more)
Being a member of a high risk ethnic group, such as Hispanic, African-American, Native American and some Asian cultures
Having sugar in your urine
Family history of diabetes
You’ve been diagnosed with gestational diabetes in a previous pregnancy
Have had an unexplained stillbirth
Have previously given birth to a baby over 9 pounds
Have a condition called polyhydramnios (too much amniotic fluid)
Previously acknowledged impaired glucose tolerance
Some women will develop gestational diabetes without having any of the common risk factors. Also, having these risk factors does not mean that you will develop gestational diabetes.
Health Problems Associated with Gestational Diabetes
Gestational diabetes is most commonly developed during the 20th – 26th week of pregnancy. If it is developed earlier in the pregnancy or the mother has diabetes (type 1 or type 2) before the pregnancy, it can result in birth defects and may increase the possibility of a miscarriage. The most common type of birth defect associated with gestational diabetes are those of the brain and heart. Read about other causes of birth defects here.
When gestational diabetes is developed over the second and third trimester the complications are less severe. It may cause over-nutrition and excessive growth of the unborn baby called macrosomia.
Giving birth to a large baby increases the risk during labor and delivery and many of these over-sized infants will end up requiring a caesarean delivery rather than a vaginal delivery. A vaginal delivery for a large baby increases the possibility of trauma to the infant and excessive tearing or other complications for the mother.
Another concern is that high blood sugar from the mother causes high insulin levels in the baby while still in utero. When the baby is delivered and the umbilical cord is cut, its blood sugar can drop very low quite rapidly. Your delivering physicians will be aware of this danger, however, and take steps accordingly following birth.
Gestational diabetes does increase risk during pregnancy and delivery, however, with proper care from family medicine doctors, women with gestational diabetes and even type 1 or 2 diabetes may safely have a healthy baby.
If you are pregnant or planning a pregnancy, see your family medicine provider to ensure that you are healthy and well-cared for before, during, and after your new addition to the family.