Among the regular examinations during pregnancy, the detection of the presence of sugar in the urine, called glycosuria, as well as their possible level is particularly monitored. Why ? Because it can be a sign of gestational diabetes, a common disorder in pregnant women that can lead to complications during childbirth as well as health problems for mother and baby. How is this test performed and how to interpret it?
As wonderful as it is, pregnancy is such a physical upheaval that it sometimes causes some dysfunction, more or less benign, of the body. This is why it must be monitored and certain specific parameters regularly checked by a doctor. This is the case with glycosuria, which is the presence of sugar (glucose) in the urine of the expectant mother. This can indeed be a harbinger of gestational diabetes and must therefore be taken very seriously.
What is glycosuria?
Sugar, unfairly criticized, is an essential element in the body that is supplied to it daily through food. It is therefore normal to find it in our blood where it is sent after digestion to be transformed or stored by the cells. This presence is called glycemia and like everything in our body, it has a certain threshold whose exceeding, lower (hypo) or higher (hyper), generally reflects a health problem.
While it is therefore normally present in the blood, sugar should not be found in the urine (or in very small quantities). This can be the result of hyperglycemia, a level of glucose in the blood that is too high for the kidneys to filter it. This presence, called glycosuria, can also be a sign of gestational diabetes.
In pregnant women, increased glycosuria is not uncommon because renal sugar filtration tends to be affected by pregnancy, but it is not systematically alarming. It must nevertheless be particularly supervised.
How is glycosuria measured?
The urine sugar screening during pregnancy is done at each follow-up medical appointment, normally monthly. This is a very simple and quick test that consists of directly analyzing the urine collected in a sterile vial using a strip that reacts to the presence of sugar.
It should be noted that this urinalysis initially makes it possible to detect a possible albuminuria (or proteinuria), that is to say the abnormal presence of albumin, a protein normally filtered by the kidneys and which should therefore not be either found in urine. It can be a sign of toxemia of pregnancy, or preeclampsia, a kidney complication that can be serious for both mother and baby.
The strips thus display several small squares whose color will change depending on the presence of certain enzymes and their concentration. A table of references allows them to be compared and thus interpreted. The number of reference shades may depend from one brand of strip to another, but the values taken into account remain the same. The values are usually indicated in milligrams / deciliter (mg / L or mmol / L) as well as with +. In the case of glucose and glycosuria, the color is most often from sky blue to dark brown through light green and khaki on 6 shades which can be read:
- Negative
- Traces = 1g / l (100mg / dl)
- + = 2.5g / l (250mg / dl)
- ++ = 5g / l (500mg / dl)
- +++ = 10g / l (1000mg / dl)
- ++++ = greater than 20g / l (2000mg / dl)
The results that should challenge and which can announce too high blood sugar and a risk of gestational diabetes begin with signs +. Obviously, your doctor is responsible for reading your urine test results.
Screening for glycosuria, what is the next step?
Has the strip reacted and shows too much glucose in the urine? Do not panic. As explained before, this is common in pregnant women and this finding should not be interpreted as a worrying sign of high blood sugar or gestational diabetes. Also, this test is not sufficient to diagnose any of these disorders.
If the doctor feels there is a risk and it is necessary to investigate further, the mother-to-be should have her blood sugar tested by OGTT (Oral Induced Hyperglycemia). This test, carried out in the laboratory and usually in the morning, consists of measuring the level of sugar in the blood in three stages. A blood test is first taken on an empty stomach. Then the pregnant woman must swallow a sugar solution which will cause hyperglycemia. His body's response will then be measured by 2 more blood tests at 1 hour after glucose ingestion, when the level should reach its peak, and at 2 hours, when it should normally come down. Blood sugar should not deviate from the following thresholds:
- 0.92g / L on an empty stomach
- 1.80g / L at H + 1
- 1.53g / L at H + 2
Beyond that, it may be gestational diabetes and specific management will need to be determined.
Focus on gestational diabetes
Glycosuria can therefore be a sign of gestational diabetes. This diabetes is different from type 1 or 2 diabetes because it is transient. It usually occurs towards the end of the second trimester and during the third trimester, but it goes away after childbirth. In France, it affects 7% of pregnant women. In the majority of cases, it is asymptomatic, but it can sometimes manifest itself with symptoms specific to "classic" diabetes such as intense thirst, profuse urine and severe fatigue. As said previously, only a blood glucose test can be used to diagnose it.
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What are the risks of gestational diabetes?
While the name diabetes is scary, gestational diabetes isn't necessarily so worrisome. On the one hand, it is temporary and goes away relatively quickly after childbirth, and on the other hand, the treatment (see below) is not heavy and in the majority of cases does not involve medication.
Gestational diabetes, however, is not without health risks, that of the mother-to-be and that of the child. It can indeed cause high blood pressure in pregnant women. It can also cause the baby to gain too much weight (macrosomia) as well as excess amniotic fluid, which can cause complications during childbirth. In the longer term, being overweight and developing type 2 diabetes can occur in children, but this is rare.
Are there predispositions to gestational diabetes?
This pregnancy-related disorder can occur in all women. However, studies have identified certain predispositions to gestational diabetes, including:
- Overweight in the expectant mother (when the BMI is greater than or equal to 25) before pregnancy
- Excessive weight gain during pregnancy
- Maternal age (over 35)
- A history of type 2 diabetes in direct family members of the pregnant woman (parents, brothers and sisters)
- A history of fetal macrosomia (baby weighing more than 4k at birth)
- Previous gestational diabetes in a previous pregnancy
- Ethnic origin. Research has actually established a prevalence of women of Asian origin, especially Chinese, to develop gestational diabetes.
While these factors have been observed to be linked to diabetes during pregnancy, they are by no means systematic factors. A woman who meets one or more of these criteria may well have a pregnancy without diabetes, as can a woman who does not meet any of them develop gestational diabetes.
However, doctors are paying more attention to screening for gestational diabetes in women with these risk factors. Thus, in addition to the search for sugar in the urine, a blood sugar measurement is carried out from the first trimester by a blood test on an empty stomach.
How is gestational diabetes treated?
After diagnosis, the majority of cases of gestational diabetes are treated with a diet that regulates the intake of sugars in the expectant mother. A daily calorie intake will be determined as well as the daily carbohydrate rate (between 250 and 180 g / d) with an emphasis on slow sugars (legumes and pasta). Meals and snacks should be regular.
Pregnant women should check their blood sugar levels themselves several times a day, on an empty stomach and around meals, and will be medically monitored every 15 days with weighing and blood pressure measurement.
When the diet is not enough and the blood sugar remains high (greater than or equal to 1.05 g / l on an empty stomach and greater than or equal to 1.40 g / L after a meal), insulin therapy, that is to say say insulin injection, can be decided by the doctor. He will then establish the injection protocol (the doses of insulin and the times of injection) which can be adapted as the treatment progresses. The mother-to-be will again have to monitor her glycosuria and blood sugar by urine test strips herself before and after meals.
Does gestational diabetes affect childbirth?
Depending on the state of blood sugar around the term, obstetric monitoring may be reinforced at the time of childbirth, as macrosomia can cause complications. Delivery may be initiated at 39 weeks or a cesarean may be recommended if the baby weighs more than 4.2 kg.
If the blood glucose targets are met, these specific measures are not considered necessary.
On the other hand, post-partum monitoring of the mother and newborn and their blood sugar is systematic. Particularly when the mother has been treated with insulin there is a risk of hypoglycemia in the infant. The injections are also stopped after birth.
Although the blood sugar level usually returns to normal postpartum, it should be checked again in the mother within 6 months, either by fasting measurement or by OGTT.
Be careful, gestational diabetes disappears after childbirth but it can reappear during a later pregnancy. Research has also shown a link between the development of gestational diabetes during pregnancy and the risk of developing type 2 diabetes during menopause.