Last Updated on March 19, 2024 by Partha Protim Choudhury
When is testing done for gestational diabetes during pregnancy?
It is tricky to detect GDM because it is mostly asymptomatic. Doctors unfailingly recommend pregnant women get themselves tested for blood sugar between the second and third trimesters. Usually, the blood glucose screening period is between 24 and 28 weeks of pregnancy. During this period, the placenta starts releasing hormones that block insulin.
Only in the case of high-risk women, like someone with obesity or PCOS, doctors do recommend blood sugar testing at the time of the first trimester.
How does gestational diabetes in pregnancy get detected?
There are two main tests to screen for gestational diabetes: the glucose challenge test and the oral glucose tolerance test. Doctors may suggest one or both blood tests.
During the glucose challenge test, also called a glucose screening test, the pregnant woman drinks a sugary drink then a healthcare provider draws blood after 1 hour. There is no fasting required beforehand. If the blood sugar level is high (usually above 140 mg/dL), the woman will need a follow-up test called an oral glucose tolerance test to confirm GDM.
The Oral Glucose Tolerance Test (OGTT) measures blood glucose after fasting for at least 8 hours. First, a healthcare professional will draw the blood from a pregnant woman. Then she drinks the liquid containing glucose. The healthcare professional will draw blood every hour for 2 to 3 hours for the diagnosis of gestational diabetes. Pregnant women will have gestational diabetes if they have high glucose levels at two or more times of testing.
In India, DIPSI (Diabetes in Pregnancy Study Group India) suggests only one step of glucose screening test for the diagnosis of GDM. A pregnant woman does not need any prior fasting. They drink a 75-gram glucose drink in 250-300 ml of water. After 2 hours, the healthcare professional draws blood and checks for blood glucose readings. If the reading is greater than 140 mg/dl, then the pregnant woman has GDM.
According to the ADA, the measurement of haemoglobin A1C is not a sensitive enough test for the diagnosis of GDM.
After 24 to 72 hours of delivery, doctors monitor blood glucose levels. The removal of the placenta should improve insulin resistance. Thus, the blood glucose level may normalise.
Both the ADA and the ACOG recommend repeated glucose testing until 1 to 3 years of delivery for a woman with GDM.
How often should I check my blood sugar while being pregnant?
Doctors recommend blood sugar testing to diagnose gestational diabetes during pregnancy between 24 and 28 weeks of pregnancy. According to the ACOG, ideal blood sugar levels during pregnancy are under 95 mg/dL before eating (fasting) and under 140 mg/dL one hour after a meal. Two hours after eating, blood sugar should be below 120 mg/dL. Higher levels are indicative of GDM.
Self-monitoring of blood sugar is crucial for managing GDM. This involves using a glucometer to check blood sugar levels four times a day. Pregnant women should take the first reading on an empty stomach. Additional checks happen one hour after the first bite of breakfast, lunch, and dinner. Regular discussions with a doctor about these readings are important to ensure proper management of GDM.
A study in 2010 suggests that to reduce inconvenience and cost, pregnant women can self-check blood sugar levels only twice. Researchers suggest it for women whose blood glucose usually stays in the target range.
Disclaimer: Medical Science is an ever evolving field. We strive to keep this page updated. In case you notice any discrepancy in the content, please inform us at [email protected]. You can futher read our Correction Policy here. Never disregard professional medical advice or delay seeking medical treatment because of something you have read on or accessed through this website or it's social media channels. Read our Full Disclaimer Here for further information.
