We know much more about diabetes in pregnancy now, and the management is always improving. Below are answers to some common questions that women and their families ask.
Gestational diabetes mellitus (GDM) is diabetes that is first discovered during pregnancy. It occurs in up to four per cent of all pregnancies. GDM usually develops during the second half of the pregnancy. It almost always goes away when the baby is born.
GDM occurs when the cells cannot make the extra insulin that you need for pregnancy. It is not caused by "eating the wrong things", although that does make it worse.
Women are checked for GDM between 24 and 28 weeks of pregnancy, and sometimes earlier if high risk factors are present.
A very small number of women have had diabetes before pregnancy and have not known it, or have developed permanent diabetes during the pregnancy. It is important to find this out so that women can take good care of themselves. Even if the team suspects that a woman with GDM has permanent diabetes, this cannot be confirmed until the baby is born. At present, the blood sugar is checked after delivery to make sure the GDM is gone. The other recommendation is to have a 75gram glucose tolerance test (GTT) at the lab between 6 weeks and 6 months after the baby is born to make sure the GDM has not come back.
GDM is a warning sign to women that they are at risk for diabetes in the future. They can then work on maintaining a healthy lifestyle.
Women with type 1 or type 2 diabetes who have high sugars during conception and for the first few weeks of pregnancy have an increased risk of birth defects. These may be very minor, or they may be major problems such as heart, brain, spinal cord, or kidney problems. Good blood sugar control also decreases risk of miscarriage, and of diabetic complications for the mother. For these reasons, we help you to maintain good daily blood sugar values for at least two to three months before conception, as well as a good HbA1c value. The HbA1c is an average value of your blood sugars over the last two or three months. Ideally, this value should be under 7.0 %.
If you are already pregnant, it is still important to have good control, because babies can have other problems from high sugars. These problems can happen with any of the types of diabetes, including gestational diabetes. Sugar passes very easily through the placenta to the baby, although insulin does not. The baby will make extra insulin to use up all the sugar, and then will store the extra sugar as fat. Babies can get very big this way (asymmetrical macrosomia). This can make labour more difficult, and increase the chance of shoulder dystocia (shoulders that are stuck), forceps, or a Caesarean birth.
When the baby is making extra insulin, the lungs do not mature as they should. If the baby is born early, it may have more difficulty with breathing than other babies of the same gestational age. This is because surfactant, which the lungs need in order to breathe properly, does not form well when the baby is getting too much sugar and has to make extra insulin.
If the baby is getting extra sugar from the mother, this stops at delivery when the cord is cut. However, the baby will still continue to make extra insulin for a while. The baby can quickly use up its sugar supply and have a low blood sugar. This is uncomfortable for the baby, and can also be dangerous.
Babies may also be jaundiced, and may need to have phototherapy (light) treatment.
Good blood sugar control in pregnancy helps to avoid these problems in types 1 and 2 diabetes. Studies are now showing an increased risk of obesity and other medical problems in childhood and onwards when the baby is exposed to high sugars during pregnancy.
Women with GDM do not have high blood sugars long enough to have diabetic complications in the mother, and with normal blood sugars the baby does not have problems either.
In early pregnancy, the baby needs to get fuel (sugar) from the mother so it can grow and develop. Sugar passes easily to the baby. This means that the mother’s blood sugar is lower, and she needs less insulin. Many mothers have less appetite, and may have nausea and vomiting, which also causes them to need less insulin.
As the pregnancy continues, the placenta (afterbirth) makes more and more pregnancy hormones. One job of these hormones is to make sure that there is enough sugar for the baby to grow. They do this by making the mother resistant to her own insulin, so that her insulin does not work very well. This means that the total amount of insulin needed per day will increase as the hormone levels increase. By the end of pregnancy, the mother needs two or three times more insulin to keep the blood sugars normal. This increase usually happens sometime after the first four months, but it can vary.
Toward the end of pregnancy, the baby is growing and kicking a lot, and Braxton-Hicks contractions start in order to help the body become ready for labour. The placenta slows down its production of hormones. All these things mean that the mother may see a drop in her insulin needs. The first sign of this might be a drop in blood sugars overnight. If insulin needs start to decrease, the team will keep a close eye on the welfare of the baby to make sure that the drop is normal.
After the baby is born, the hormone levels drops because the placenta is gone. The mother becomes very sensitive to her own insulin again. Those with type 1 may not require any insulin for up to 48 hours. Insulin is restarted as needed when the sugars start to rise. Women with type 2 may or may not require insulin or pills, and this will be decided with the endocrinologist. It is unusual for women with GD or AGT to need to take insulin after delivery.