During pregnancy, your prenatal visits involve a lot of testing to ensure your baby's healthy development. Tests for blood type, previous infections and preventive screenings ensure you and your baby are healthy and safe. The blood glucose test is one such test, a preventive measure to detect gestational diabetes, which affects three to eight out of 100 pregnant women, says The National Diabetes Information Clearinghouse.
What is Gestational Diabetes?
Gestational diabetes occurs when blood sugar levels become uncontrolled during pregnancy. By definition, it is a type of diabetes that only occurs during pregnancy, so women diagnosed do not have diabetes before pregnancy. Hormones and weight gain are factors in developing gestational diabetes, adversely affecting insulin activity in the body. Your risk for gestational diabetes increases if you had the condition with a previous pregnancy, have given birth to a baby over 9 lbs, are over 25 years old, have had family members with diabetes, were diagnosed with pre-diabetes before pregnancy or were overweight before pregnancy. If your risk factors are higher, your doctor may test your blood sugar earlier in pregnancy.
Blood Sugar Testing During Pregnancy
A screening glucose test typically occurs between the 24th and 28th weeks of pregnancy. You are asked to eat normally and then to drink a sugary drink before your prenatal visit. You'll have your blood drawn to measure how the drink affected your blood sugar when you arrive at the visit. If your result is above normal limits, your doctor will ask for follow-up blood sugar testing, called the oral glucose tolerance test. Fasting for eight to 10 hours before this test is required. Your blood is then drawn when you first arrive for your visit; you then drink a sugary drink and are given subsequent blood tests at the 1-hour, 2-hour and 3-hour mark after the drink. If your blood sugar is abnormal for two of the blood draws, you have gestational diabetes. If you are given a 100 g sugary drink during your glucose tolerance test normal results are below 95 mg/dL for the fasting blood draw; less than 180 mg/dL at the 1-hour blood draw; less than 155 mg/dL at the 2-hour blood draw; and less than 140 mg/dL at the 3-hour blood draw.
Additional Facts about Blood Sugar Testing
You should eat normally the days preceding the glucose tolerance test. Fasting is only necessary eight to 10 hours before the test, and includes no drinking and eating. When you arrive for the test, you are not allowed to eat, so your total fasting time includes your time at the office. After drinking the sugary drink, some patients report feeling nauseated and sweaty. Factors such as acute stress and vigorous exercise can affect test results, so try to stay relaxed and not overdo exercise around the time of testing. Some medications can affect the blood glucose test results, too, including psychiatric medications, beta blockers, corticosteroids, birth control pills and some diuretics, notes MedlinePlus. Make sure your doctor knows you are taking these medications before testing.
Considerations
Gestational diabetes often has no symptoms, but increases the risk for high blood pressure during pregnancy, called pre-eclampsia. It also increases the chances for a large-weight baby and the need for a cesarean delivery. If you are diagnosed with gestational diabetes, your obstetrician will counsel you on meal planning, proper exercise and possible home blood sugar testing and insulin use. You'll also be closely monitored with testing, such as "kick counts" and more ultrasounds during prenatal visits. Luckily, gestational diabetes usually goes away after pregnancy.
