In the past, women with diabetes were at high risk for complications during pregnancy. Today, with advancements in treatment and good blood glucose control, women with diabetes can have a safe pregnancy and delivery similar to that of a woman without diabetes.
(Please note: this article focuses on pre-existing diabetes, which refers to women who have diabetes before becoming pregnant. This is different than gestational diabetes, which occurs during pregnancy.)
Planning your pregnancy
For women who have diabetes, obtaining preconception (‘before pregnancy’) care is associated with better birth outcomes. By discussing pregnancy with your healthcare team prior to conception, they can help you reach your blood glucose targets, start folic acid supplementation and discontinue potentially harmful medications to lay the groundwork for a healthy pregnancy.
Blood glucose targets
It is important that woman who are planning a pregnancy get their preconception A1C levels to less than 7%, or as close to normal as can be achieved safely. This will decrease the risk of spontaneous abortion, birth defects and pregnancy-induced high blood pressure (this is known as ‘preeclampsia’). Good blood glucose control in pregnancy is important, because high blood glucose levels can cause the baby’s size and weight to be larger than average and increase the risk of complications during and after delivery.
Women should speak to their healthcare team, as blood glucose targets change in pregnancy; hence, more frequent blood glucose monitoring is recommended to ensure these goals are being met. Hypoglycemia can be more common in the first trimester of pregnancy; therefore, monitoring and adjustment of insulin doses, as needed, are both very important during this time. The risk of hypoglycemia may be lower if women achieve good glycemic control prior to becoming pregnant.
Taking 5 mg of folic acid, either alone or within a multivitamin, is recommended at least three months before a woman becomes pregnant until three months into her pregnancy. After this, folic acid supplementation should continue, but can be decreased to 0.4 mg to 1 mg daily until six weeks after delivery or until breastfeeding stops.
Discontinue medications that can cause harm
Medications that are normally used to treat high blood pressure are not safe for the fetus and should be discontinued in women who are planning pregnancy. These include: angiotensin-converting-enzyme inhibitors (also known as ACE inhibitors), such as enalapril, captopril and lisinopril; and angiotensin receptor blockers (also known as ARBs), such as valsartan and losartan. If not discontinued before becoming pregnant, they should be stopped as soon as pregnancy is detected. Blood pressure control is still important, but there are safer alternatives for pregnant women, such as calcium channel blockers, labetalol or methyldopa.
Medications used to treat high cholesterol can also have harmful effects on the unborn fetus. The family of drugs called statins (for example, atorvastatin or rosuvastatin) should be discontinued prior to pregnancy. Although it is still important to keep cholesterol levels down, it is recommended that women should switch to other types of medication and also attempt to lower cholesterol levels through diet and exercise. It is important to limit saturated fat by using monounsaturated oils (such as olive and canola oils), and avoid processed and fried foods. Adding more fibre by eating vegetables, whole grains, beans and legumes is also helpful .
Prior to conception, woman with type 2 diabetes who are taking oral medications should be stopped, and insulin should be started and titrated to achieve optimal blood glucose levels. However, metformin and glyburide may be continued – during the first trimester – until insulin is started, in order to avoid severe hyperglycemia, which can harm the baby.
For optimal glycemic control in pregnancy in women with pre-existing diabetes, multiple doses of rapid-long acting insulins usually have the best results controlling blood glucose levels. Rapid-acting insulins (for example, insulin aspart or insulin lispro) appear to be safe for use in pregnancy and show improvement in blood sugars after meals, with reduced hypoglycemia. NPH (an intermediate-acting insulin) and detemir (a long-acting insulin) both appear safe in pregnancy as well. However information regarding glargine (another long-acting insulin) is limited with regard to safety in pregnancy, and is therefore less desirable.
Use of insulin pumps
Women with type 1 diabetes using pump therapy should be aware of the increased risk of diabetic ketoacidosis in the event of insulin pump failure, as it is a potentially fatal complication for the unborn baby.
All women should be encouraged to breastfeed, as it has numerous benefits to both babies and mothers. Women with diabetes who are breastfeeding should continue to avoid any medicines for the treatment of diabetes complications that were discontinued for safety reasons in the preconception period. Insulin requirements may be lower while breastfeeding, and frequent blood glucose monitoring is important to prevent severe hypoglycemia.
Mothers with type 1 diabetes are recommended to have a snack before breastfeeding to avoid low blood sugar levels.
Metformin and glyburide may be considered for use in breastfeeding for type 2 diabetes; however further long-term studies are needed to better understand the safety of these drugs. Newer diabetes medications (for example, incretins and SGLT-2 inhibitors) have not been studied regarding use in breastfeeding, so they should not be taken during this time. Therefore, insulin currently remains the optimal diabetes treatment during lactation.
Planning ahead with the help of your healthcare team can ensure that women with pre-existing diabetes can have a safe and healthy pregnancy.