Pregnancy is a wondrous and exciting time. It’s a time of change, both physically and emotionally. With the proper attention and prenatal medical care, most women with diabetes can enjoy their pregnancies and welcome a healthy baby into their lives.
Why Tight Blood Sugar Control Is Critically Important
Blood sugar control is important from the first week of pregnancy all the way until delivery. Organogenesis takes place in the first trimester. Uncontrolled blood sugar during the early weeks of pregnancy increases the risk of miscarriage, and birth defects. (Women don’t develop gestational diabetes until later in pregnancy, which means they don’t share these early pregnancy risks.)
Later in the pregnancy, uncontrolled blood sugar levels can cause fetal macrosomia, which may lead to shoulder dystocia, fractures, and the need for Cesarean section deliveries. Very high blood sugar levels can increase the risk of stillbirth.
Maternal hyperglycemia can stimulate fetal hyperinsulinemia, and lead to neonatal hypoglycemia when the glucose supply (umbilical cord) is cut.
Because of all these increased risks, home deliveries are not typically recommended for women with any form of diabetes.
As many as two thirds of all women with diabetes have unplanned pregnancies and most women don’t realize that they’re pregnant until six or more weeks into the pregnancy. That’s why it’s critically important for women who have diabetes to use contraception and achieve tight blood sugar control prior to conception. Many health-care providers suggest at least three to six months of stable blood sugar control prior to attempting to conceive. Hemoglobin A1c should be within 1 percentage point above the lab normal, which means striving for a HbA1c of less than 7 percent.
Women using oral agents should be switched to insulin prior to becoming pregnant. Oral agents are contraindicated in pregnancy. It’s also important to make sure that any other prescription drugs or over-the-counter medications that are being used are safe for pregnancy.
Typical Blood Sugar Targets During Pregnancy
Fasting blood sugar:
< 95 mg/dl if meter reads whole blood.
< 105 mg/dl if meter is plasma calibrated.
Blood sugar level measured 1 hour after the meal:
< 140 mg/dl if meter reads whole blood.
< 155 mg/dl if meter is plasma calibrated.
Calorie requirements increase by 300 calories per day during months 4-9. Most women end up needing a total of about 2,000-2,200 calories per day. Weight should be monitored and calories adjusted to ensure appropriate weight gain.
A minimum of 1,700-1,800 calories per day is recommended during pregnancy. Eating too few calories or too few carbohydrates can cause the production of ketones. Ketones can pass through the placenta and may have a negative impact on the fetus.
Diabetes during pregnancy is one situation when a slightly lower carbohydrate intake may be prudent. I usually recommend that 40-50 percent of the calories come from carbohydrate. I have women start with the lower end and move up as tolerated. (Women using insulin often tolerate 45-50 percent, as insulin can be adjusted to cover.) Excessive carbohydrate intake may make it difficult to maintain the strict blood sugar control required during pregnancy. It’s equally important to ensure adequate carbohydrate intake. If too little carbohydrate is eaten, then important nutrients from the carbohydrate food groups may be lacking. Grains, milk, and fruits are each important components of a healthful diet.
Calorie Level Grams of carbohydrate needed to provide 40-50 % of total calories
Once carbohydrate goals are determined, it’s important to distribute the carbohydrate intake throughout the day. Eating too much at one time can cause the blood glucose to go dangerously high. It works best to split the carbohydrate budget between three meals and two to four snacks–for example, 45-60 grams of carbohydrate for each main meal and 15-30 grams of carbohydrate for each snack. (Note: some women do best to limit breakfast to 30 grams of carbohydrate secondary to hormonally mediated glucose intolerance that commonly occurs in the morning.)
Dietary Strategies for Controlling the Blood Sugar
*Distribute carbohydrate between three meals and two to four snacks. Distributing the carbohydrate throughout the day allows the body to process it one batch at a time.
*Milk and fruit are both healthful choices. However, they tend to digest rather quickly, which means that the glucose derived from those foods enters the bloodstream rapidly. To prevent spiking post-meal blood sugar levels, it’s recommended to eat those foods one portion at a time.
*Avoid fruit juices, regular soft drinks and sugary beverages.
*Avoid added sugars. That includes natural sugars, honey, and syrups. Every bite should count toward good nutrition
*Breakfast matters: Because of hormones, blood sugar levels can be especially difficult to control at breakfast time. For women with elevated post-breakfast blood glucose values, it helps to avoid milk, fruit, and refined breakfast cereals at the breakfast meal (since those foods digest so quickly). Milk and fruit should still be included, but at meals or snacks other than breakfast. A breakfast that consists of starch plus protein may be better tolerated. Another option is to limit breakfast to 30 grams of carbohydrate and distribute the remaining carbohydrate between the other meals and snacks. But don’t skip breakfast.
Blood glucose monitoring is crucial. If the above dietary guidelines are being followed, and blood glucose cannot be maintained within target levels, then insulin should be added or adjusted until control is achieved.
SHERRI SHAFER received her BS in Nutrition and Dietetics from the University of California at Berkeley. She has been a Dietitian at UCSF Medical Center for 10 years. Sherri specializes in medical nutrition therapy counseling for individuals in adult and pediatric diabetes clinics, and is an Instructor for classes on diabetes self management for Type 1 and Type 2 diabetes. She has just completed her first book, Diabetes Type 2 Complete Food Management Program from Prima Publishing.