Diabetes in Pregnancy
Diabetes is a disorder that prevents the body from using food properly. Normally, the body's main source of energy is glucose. After being digested in the stomach, sugars and starches enter the bloodstream in the form of glucose, a sugar that becomes a source of energy. The body uses the hormone insulin to get the glucose from the bloodstream to the muscles and other tissues of the body.
The role of insulin
Insulin is manufactured by the pancreas, a gland lying behind the stomach. Without insulin, glucose cannot get into the cells of the body, where it is used as fuel. Instead, high levels of glucose accumulate in the blood, from where it spills into the urine via the kidneys. This is known as diabetes.
Types of diabetes
If you have diabetes before pregnancy (that is, preexisting diabetes), it will be one of two types: Type I, or insulin-dependent diabetes mellitus (IDDM) formerly called juvenile onset diabetes. This results from the failure of the pancreas to produce enough insulin.
Type II, or non-insulin-dependent diabetes mellitus (NIDDM) formerly called maturity onset diabetes.This is caused by the body becoming resistant to insulin so that it cannot use it efficiently. Common symptoms include frequent passing of urine, exceptional thirst and a dry mouth.
Diabetes and pregnancy
Pregnancy itself makes the body resistant to insulin because of the anti-insulin effects of the pregnancy hormones released from the placenta. In normal pregnancy, the body produces almost double the amount of insulin. However, if the pancreas fails to produce enough insulin, pre-existing diabetes can become worse or diabetes can develop for the first time.
All antenatal clinics routinely test urine for the presence of glucose. Pregnant women normally excrete glucose in their urine, particularly after eating a sugary snack or meal. Therefore, almost all women have glucose in their urine at some stage. Further tests are necessary to reliably diagnose diabetes.
Risks of poorly controlled diabetes
Poorly controlled diabetes during pregnancy can have adverse effects on both mother and baby.
Risks to the mother
There is a greater risk of miscarriage, pre-eclampsia and infection, particularly of the urinary tract and respiratory system. In addition, the high-risk nature of these pregnancies increases the likelihood of a caesarean section being necessary.
Risks To the baby
Excess glucose from blood of a mother with preexisting diabetes can cross the placenta and enter the fetus, causing abnormalities, particularly during the first 3 months, when most of the organs are forming. Common abnormalities include heart, skeleton and neural tube defects (for example, spina bifida). Fetuses of diabetic women are often larger but their growth may be restricted. There is also an increased risk of the baby dying during late pregnancy and the few weeks after the birth by 5-10-fold. In addition, newborn babies sometimes suffer from complications, for example, respiratory distress syndrome and jaundice.
If you have diabetes and are planning to become pregnant, you should talk to your doctor first. He can explain about any possible risks and can arrange for you to receive the best advice and care both before and throughout your pregnancy.
pre-conceptual counselling It is very important to get counselling about good diabetic control when you are planning to become pregnant. This can significantly reduce the risk of your baby having a congenital abnormality, as well as improving the outcome of your pregnancy. Talk to your doctor about improving the management of your diabetes and, as in all pregnancies, take folic acid to reduce the risk of spina bifida.
Your doctor should refer you to a specialized clinic, where you can see an obstetric/diabetic team, that is, an obstetrician, midwife, diabetic physician, diabetic nurse, dietician and ophthalmologist (to check for any diabetic damage to the retina of the eye).
The main aim is to achieve near-normal glucose levels. This entails:
- Frequent monitoring of your blood glucose, which you do at home.
- Changes in your insulin dosage if necessary.
- Avoiding oral diabetic drugs in pregnancy because these can cause low blood-glucose levels in your developing baby.
- Paying particular attention to your diet: a low-sugar, low-fat, high-fibre diet with regular snacks can prevent your blood-glucose levels falling too low.
- A detailed anomaly scan at 20 weeks to check your baby for structural abnormalities.
- Serial scans to check your baby's growth and the amount of amniotic fluid surrounding your baby. (This is sometimes raised in diabetic pregnancies, a condition known as polyhydramnios.) Delivery will usually be planned for 38-39 weeks, with the options of:
- Induction of labour.
- caesarean section. You may be given intravenous infusions of insulin and dextrose during your labour to control your blood-glucose levels.
About 5 per cent of women, especially those from the Indian subcontinent and southeast Asia, develop diabetes for the first time in pregnancy. As well as the implications for the pregnancy, women with gestational diabetes have a 50 per cent risk of developing Type II diabetes within the next 10-15 years.
Many units screen women who are at particular risk, for example, those with a personal or family history of gestational diabetes, a previous large baby or a large baby in the current pregnancy, unexplained stillbirth, obesity, high levels of glucose in the urine (glycosuria) and excess amniotic fluid (polyhydramnios). Different screening tests are available. If your doctor suspects that you have gestational diabetes, he will arrange for you to have a formal 'glucose-tolerance test' to establish the diagnosis. This test measures your blood-glucose levels after you have taken a sweet glucose drink.
In most cases, gestational diabetes will respond to a low-fat, increased fibre and altered carbohydrate intake. Avoiding sugary foods can lead to improvements, although insulin may become necessary. Regular scans to check your baby's growth are advisable.