Maternal health and fetal complications are at a much greater risk in women with diabetes who are pregnant. Even the stress of a pregnancy can bring about gestational diabetes, which is a form of glucose intolerance that begins during the pregnancy and resolves itself after the birth of the baby. Whether there is preexisting diabetes or gestational diabetes there is an increased risk of fetal congenital defects and death from hyperglycemia, or abnormally high blood sugar, which must be controlled. Any woman with diabetes that is pregnant should get some form of nutritional counseling from a registered dietician.

There are many changes that occur during a pregnancy that can have detrimental effects on controlling the diabetes and the use of insulin. The placenta produces some hormones and enzymes that reduce the effectiveness of insulin. Insulin from the mother does not cross the placenta but blood glucose will. If too much blood glucose crosses over to the baby the baby's pancreas will increase insulin production. This increase in insulin leads to a condition that is typical for women with diabetes, macrosomia, or big baby syndrome. Newborns of mother with either form of diabetes can also suffer from respiratory problems, hypocalcemia, hypoglycemia, hypokalemia, or jaundice.

Medical nutrition therapy needs to be individualized based on the mother's weight and height. The diet plan used by a pregnant woman should include adequate calories and nutrients to meet the needs of both mother and fetus and should be consistent with established maternal blood glucose goals. The impact of meals and snacks on blood glucose levels must be tracked with self monitoring and should be done a minimum of four times a day.

Planning and commitment is required for any pregnant woman with diabetes to have a successful pregnancy. Achieving and maintaining tight blood glucose control before conception and during the first trimester is of paramount importance because this is when most fetal malformation occurs. The best time for any woman with diabetes who is attempting to become pregnant is before conception.

During the second and third trimesters the need for insulin increases because of increased blood glucose levels caused by the increased production of hormones associated with pregnancy that decrease the effectiveness of insulin.

A diabetic pregnancy will require a more focused approach to the diabetic diet plan each day of the pregnancy. Special considerations need to be made for food cravings and nausea during the early weeks of a pregnancy. All meal plans need to be individualized to each woman and need to evolve throughout the pregnancy as insulin and nutritional needs change.