Nashville Diabetes Dentist

The goal of treatment is to reduce the risks of GDM for mother and child. Scientific evidence is beginning to show that controlling glucose levels can result in less serious fetal complications (such as macrosomia) and increased maternal quality of life. Unfortunately, treatment of GDM is also accompanied by more infants admitted to neonatal wards and more inductions of labour, with no proven decrease in cesarean section rates or perinatal mortality. These findings are still recent and controversial.

A repeat OGTT should be carried out 2–4 months after delivery, to confirm the diabetes has disappeared. Afterwards, regular screening for type 2 diabetes is advised.

If a diabetic diet or G.I. Diet, exercise, and oral medication are inadequate to control glucose levels, insulin therapy may become necessary.

The development of macrosomia can be evaluated during pregnancy by using sonography. Women who use insulin, with a history of stillbirth, or with hypertension are managed like women with ouvert diabetes.

Counselling, lifestyle, and monitoring

Counselling before pregnancy (for example, about preventive folic acid supplements) and multidisciplinary management are important for good pregnancy outcomes. Most women can manage their GDM with dietary changes and exercise. Self monitoring of blood glucose levels can guide therapy. Some women will need antidiabetic drugs, most commonly insulin therapy.

Any diet needs to provide sufficient calories for pregnancy, typically 2,000 – 2,500 kcal with the exclusion of simple carbohydrates. The main goal of dietary modifications is to avoid peaks in blood sugar levels. This can be done by spreading carbohydrate intake over meals and snacks throughout the day, and using slow-release carbohydrate sources—known as the G.I. Diet. Since insulin resistance is highest in mornings, breakfast carbohydrates need to be restricted more.

Regular moderately intense physical exercise is advised, although there is no consensus on the specific structure of exercise programs for GDM.

Self monitoring can be accomplished using a handheld capillary glucose dosage system. Compliance with these glucometer systems can be low. Target ranges advised by the Australasian Diabetes in Pregnancy Society are as follows:

• fasting capillary blood glucose levels <5.5 mmol/L
• 1 hour postprandial capillary blood glucose levels <8.0 mmol/L
• 2 hour postprandial blood glucose levels <6.7 mmol/L

Regular blood samples can be used to determine HbA1c levels, which give an idea of glucose control over a longer time period.

Research suggests a possible benefit of breastfeeding to reduce the risk of diabetes and related risks for both mother and child.

Medication

If monitoring reveals failing control of glucose levels with these measures, or if there is evidence of complications like excessive fetal growth, treatment with insulin might become necessary. The most common therapeutic regime involves premeal fast-acting insulin to blunt sharp glucose rises after meals. Care needs to be taken to avoid low blood sugar levels (hypoglycemia) due to excessive insulin injections. Insulin therapy can be normal or very tight; more injections can result in better control but requires more effort, and there is no consensus that it has large benefits.

There is some evidence that certain oral glycemic agents might be safe in pregnancy, or at least, are significantly less dangerous to the developing fetus than poorly controlled diabetes. Glyburide, a second generation sulfonylurea, has been shown to be an effective alternative to insulin therapy. In one study, 4% of women needed supplemental insulin to reach blood sugar targets.

Metformin has shown promising results. Treatment of polycystic ovarian syndrome with metformin during pregnancy has been noted to decrease GDM levels. A recent randomized controlled trial of metformin versus insulin showed that women preferred metformin tablets to insulin injections, and that metformin is safe and equally effective as insulin. Severe neonatal hypoglycemia was less common in insulin-treated women, but preterm delivery was more common. Almost half of patients did not reach sufficient control with metformin alone and needed supplemental therapy with insulin; compared to those treated with insulin alone, they required less insulin, and they gained less weight. There remains a possibility of long-term complications from metformin therapy, although follow-up at the age of 18 months of children born to women with polycystic ovarian syndrome and treated with metformin revealed no developmental abnormalities.

Prognosis

Gestational diabetes generally resolves once the baby is born. Based on different studies, the chances of developing GDM in a second pregnancy are between 30 and 84%, depending on ethnic background. A second pregnancy within 1 year of the previous pregnancy has a high rate of recurrence.

Women diagnosed with gestational diabetes have an increased risk of developing diabetes mellitus in the future. The risk is highest in women who needed insulin treatment, had antibodies associated with diabetes (such as antibodies against glutamate decarboxylase, islet cell antibodies and/or insulinoma antigen-2), women with more than two previous pregnancies, and women who were obese (in order of importance). Women requiring insulin to manage gestational diabetes have a 50% risk of developing diabetes within the next five years. Depending on the population studied, the diagnostic criteria and the length of follow-up, the risk can vary enormously. The risk appears to be highest in the first 5 years, reaching a plateau thereafter. One of the longest studies followed a group of women from Boston, Massachusetts; half of them developed diabetes after 6 years, and more than 70% had diabetes after 28 years. In a retrospective study in Navajo women, the risk of diabetes after GDM was estimated to be 50 to 70% after 11 years. Another study found a risk of diabetes after GDM of more than 25% after 15 years. In populations with a low risk for type 2 diabetes, in lean subjects and in patients with auto-antibodies, there is a higher rate of women developing type 1 diabetes.

Children of women with GDM have an increased risk for childhood and adult obesity and an increased risk of glucose intolerance and type 2 diabetes later in life. This risk relates to increased maternal glucose values. It is currently unclear how much genetic susceptibility and environmental factors each contribute to this risk, and if treatment of GDM can influence this outcome.

There are scarce statistical data on the risk of other conditions in women with GDM; in the Jerusalem Perinatal study, 410 out of 37962 patients were reported to have GDM, and there was a tendency towards more breast and pancreatic cancer, but more research is needed to confirm this finding.

Complications

GDM poses a risk to mother and child. This risk is largely related to high blood glucose levels and its consequences. The risk increases with higher blood glucose levels. Treatment resulting in better control of these levels can reduce some of the risks of GDM considerably.

The two main risks GDM imposes on the baby are growth abnormalities and chemical imbalances after birth, which may require admission to a neonatal intensive care unit. Infants born to mothers with GDM are at risk of being both large for gestational age (macrosomic) and small for gestational age. Macrosomia in turn increases the risk of instrumental deliveries (e.g. forceps, ventouse and caesarean section) or problems during vaginal delivery (such as shoulder dystocia). Macrosomia may affect 12% of normal women compared to 20% of patients with GDM. However, the evidence for each of these complications is not equally strong; in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study for example, there was an increased risk for babies to be large but not small for gestational age. Research into complications for GDM is difficult because of the many confounding factors (such as obesity). Labelling a woman as having GDM may in itself increase the risk of having a caesarean section.

Neonates are also at an increased risk of low blood glucose (hypoglycemia), jaundice, high red blood cell mass (polycythemia) and low blood calcium (hypocalcemia) and magnesium (hypomagnesemia). GDM also interferes with maturation, causing dysmature babies prone to respiratory distress syndrome due to incomplete lung maturation and impaired surfactant synthesis.

Unlike pre-gestational diabetes, gestational diabetes has not been clearly shown to be an independent risk factor for birth defects. Birth defects usually originate sometime during the first trimester (before the 13th week) of pregnancy, whereas GDM gradually develops and is least pronounced during the first trimester. Studies have shown that the offspring of women with GDM are at a higher risk for congenital malformations. A large case-control study found that gestational diabetes was linked with a limited group of birth defects, and that this association was generally limited to women with a higher body mass index (≥ 25 kg/m²).It is difficult to make sure that this is not partially due to the inclusion of women with pre-existent type 2 diabetes who were not diagnosed before pregnancy.

Because of conflicting studies, it is unclear at the moment whether women with GDM have a higher risk of preeclampsia. In the HAPO study, the risk of preeclampsia was between 13% and 37% higher, although not all possible confounding factors were corrected.

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