Pregnancy Glucose Test
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| Pregnancy glucose test |
What is a normal glucose test result for pregnancy?
This is a test that no longer concerns all pregnant women, only those who have risk factors. What is the gestational diabetes test, also called the OGTT test? We explain.
The World Health Organization defines gestational diabetes as a form of diabetes, a disorder of glucose regulation leading to hyperglycemia (increased blood sugar levels) of varying severity, beginning or first diagnosed during pregnancy, and most often disappearing after delivery.
The test for detecting gestational diabetes, or pregnancy diabetes, has evolved in recent years. Not all women are affected anymore.
Who is concerned by gestational diabetes screening? Is it mandatory?
From the first trimester, a search for sugar in the urine, or glycosuria, is requested. This test is carried out systematically, at each monthly pregnancy follow-up consultation, at the same time as albuminuria. However, if glycosuria can highlight hyperglycemia, it is not sufficient on its own to diagnose gestational diabetes. It is therefore not, strictly speaking, a screening test for gestational diabetes.
Currently and since 2010, the gestational diabetes test is no longer systematic. Called the OGTT test (replacing the O'Sullivan test), for hyperglycemia induced by oral administration, it is only reserved for women with risk factors, or signs suggesting gestational diabetes (high uterine height, polyhydramnios, "big baby" ...).
For these women, the HGPO test is strongly recommended but not explicitly mandatory: it will be proposed by the gynecologist or midwife who is monitoring the pregnancy, and may be accepted or refused by the patient, who will be informed of the potential complications of undiagnosed and untreated gestational diabetes (risk of pregnancy-induced hypertension or even preeclampsia, "big" baby, cesarean section, hypoglycemia in the newborn, etc.).
Pregnant women are concerned.
Below are the pregnant women considered at risk of gestational diabetes, and who are therefore invited to do this OGTT test:
- Pregnant women over 35 years old,
- Those whose body mass index (BMI) is greater than or equal to 25 (overweight or obese),
- those with a personal history or a first-degree family member with diabetes (father, mother, brother, sister),
- Women who had gestational diabetes during a previous pregnancy,
- And those who have already given birth to a baby weighing more than 4 kg (macrosomia).
It should be noted that only one of these criteria is enough for the OGTT test to be strongly recommended, because the risk of gestational diabetes is considered significant.
he OGTT, or oral glucose tolerance test: how does it work?
This is a test that must be carried out on an empty stomach (for at least 8 hours, and ideally, for 10 to 12 hours), in a medical analysis laboratory.
It goes as follows:
- an initial fasting blood test , for a fasting blood sugar measurement without ingesting glucose;
- ingestion of 75 g of glucose diluted in 200 ml of water ;
- a 2nd blood test 1 hour after taking this dose of sugar;
- a 3rd blood test 2 hours after taking it.
" In fact, we increase blood sugar levels higher than normal, to see if the pregnant woman's body tolerates sugar well or not. Then, we will look at the blood sugar values obtained, to diagnose possible gestational diabetes ," summarizes Dr. Ohayon, obstetrician-gynecologist.
Discomfort, vomiting, duration: what you need to know
The duration of the test is an element to take into account when planning this analysis. It takes 2 to 2.5 hours in total , hence the importance of bringing something to keep you busy in the laboratory (music, reading, a sufficiently charged smartphone, etc.).
It should also be noted that some women report having difficulty drinking this ultra-sweet drink, while others have no difficulty swallowing it. Some patients advise drinking it all at once to avoid feeling nauseous , because any vomiting cancels the screening, and you then have to start all over again, another day. Or opt for a less effective alternative (postprandial blood sugar, after a large meal).
If you are worried about feeling unwell, especially if you have trouble tolerating fasting or if you know you are prone to nausea and vomiting, you can plan, if possible, for a loved one to be present . He or she will be able to reassure you and encourage you to pass the test.
Values, results and conclusions:
Results are generally known 12 to 48 hours after the measurements , a duration that varies depending on the laboratory.
The diagnosis of gestational diabetes is made when the pregnant woman exceeds one or more of the following thresholds:
- 0.92 g/l fasting (or 5.1 mmol/L)
- 1.80 g/l at 1 hour after ingestion (or 10 mmol/L)
- and 1.53 g/l at 2 hours (8.5 mmol/L).
Important clarification: just one of these values is enough to diagnose gestational diabetes.
Note that sometimes the gestational diabetes test actually reveals pre-existing and previously unrecognized, undiagnosed type 2 diabetes.
In which month should this blood sugar test be done?
" The OGTT test should be performed between the 24th and 28th week of amenorrhea ," says Dr. Ohayon, or between 22 and 26 weeks of pregnancy. In other words, between the very end of the fifth month and the end of the sixth month of pregnancy, at the end of the 2nd trimester of pregnancy.
Fasting Pregnancy Glucose Test: Can You Drink Water? What to Eat Afterward?
" It is possible to drink water before performing an OGTT test, however I would advise against drinking too much , as this actually dilutes the sugar in the blood, and therefore can distort the test ," says Dr. Ohayon.
Once the test is done, there are no special precautions, you can continue to live normally and eat as much as you want.
Contraindications to the HGPO test
There are contraindications to performing an OGTT test, because it can be poorly tolerated and cause complications. The OGTT test is therefore not recommended in cases of bypass or sleeve , two devices resulting from bariatric surgery, in the treatment of obesity . In these configurations, the OGTT test can indeed cause dumping syndrome , i.e. a general malaise resulting from the sudden arrival of all this sugar in the small intestine. In these cases, pregnant women are instead offered a fasting blood sugar test as well as a postprandial blood sugar test, after a good meal.
