Type 1 diabetes mellitus (T1DM) is associated with a higher risk of complications during pregnancy, both for the mother and the developing fetus. These can often be prevented with careful management. This article outlines current guidelines regarding T1DM management before and during pregnancy.
Before pregnancy
Pre-conception tests should include:
- Measuring the HbA1c level (to assess glycemic control);
- Blood creatinine level and the presence of protein in the urine (to assess kidney damage due to diabetes and/or hypertension – nephropathy);
- Blood pressure measurement;
- Thyroid function tests;
- Eye examination (to check for retinopathy – eye damage due to diabetes).
Any abnormalities should be corrected before pregnancy. Some drugs such as ACE inhibitors (for high blood pressure) or cholesterol-lowering drugs are unsafe during pregnancy and should be discontinued or substituted. Insulin (both rapid and long-acting) is considered safe. Some women may benefit from taking low doses of Aspirin to prevent certain complications, such as pre-eclampsia (high blood pressure and protein loss in the urine).
Folic acid should be given before and during the first trimester of pregnancy to lower the risk of fetal malformations.
Glycemic control
The goal is an HbA1c level of <7.0% before pregnancy. The HbA1c level should be monitored every 2–4 weeks during pregnancy with a target level of <6% in the second and third trimester. Hypoglycemia (low blood sugar) must be avoided.
Tight glycemic control requires well-timed insulin treatment (with meals), diet and frequent monitoring of glucose levels. Women at higher risk of hypoglycemia may need continuous glucose monitoring to prevent hypoglycemia.
Pregnant women require more insulin, especially during the last trimester. However, quickly after birth, insulin requirements drop to approximately 60% of the dose needed during pregnancy. It is important to be aware of these changes and adjust insulin doses accordingly.
Treating diabetes-related complications and hypertension
High blood pressure and nephropathy increase the risk of pre-eclampsia and preterm delivery. The risk can be reduced by maintaining blood pressure <135/85 mmHg and urinary albumin (a type of protein) <300 mg per day.
Retinopathy can become worse during pregnancy. Eye examinations and proper treatment should be sought before conception.
Other hormonal disturbances, such as thyroid dysfunction, are common in women with diabetes. Treatment for low thyroid hormone levels should be started before pregnancy.
Lifestyle recommendations
Moderate physical activity (30 minutes/day) is recommended according to individual ability. This reduces the risks of pre-eclampsia and preterm delivery, and improves physical fitness and emotional wellbeing.
A diet for pregnant women with T1DM is designed to avoid single large meals and simple carbohydrates (refined sugars, candy). Insulin doses need to be adjusted according to carbohydrate intake.
Monitoring the baby
Close observation of the fetus and newborn baby are essential. Women with T1DM should have frequent ultrasounds to detect fetal malformations or excessive fetal growth. The timing and mode of delivery should be planned taking all aspects of maternal and fetal health into account.
Labor and breastfeeding
More than 50% of women with diabetes give birth by planned caesarean section. Breastfeeding provides health benefits for mother and baby and is strongly encouraged.
In summary, management of pregnant women with T1DM consists of a combination of tight glycemic control (with insulin analogues) while avoiding hypoglycemia; review and adjustment of all medications; standard pregnancy supplements (i.e. folic acid); treatment of hypertension and diabetes-related complications; and close surveillance of the embryo and newborn.
Rigorous management prevents maternal and fetal complications and improves the health of the newborn
Published By :
Nature Reviews Endocrinology
Date :
Nov 01, 2012
