What Is Gestational Diabetes?

woman holding stomach

Gestational diabetes is a type of diabetes that appears during pregnancy, usually in the 2nd or 3rd trimester. Doctors also speak of gestational diabetes when glucose intolerance (prediabetic condition) is detected in a pregnant woman. In other words, gestational diabetes is not always straightforward diabetes, but in all cases, blood sugar (or “sugar” levels in the blood) are above normal.

Sometimes the diabetes was present before the pregnancy, but had not yet been detected. A blood glucose test is performed on pregnant women in early pregnancy. This makes it possible to quickly treat women with gestational diabetes, and to strictly control their sugar level (glycemia) from conception, which allows the reduction of spontaneous abortions, malformations such as macrosomia (child of too high weight) and perinatal complications (around the time of childbirth).

In the United States, gestational diabetes is a growing concern: it now affects about 2 to 10% of pregnant women, according to the CDC. The rate is much higher in indigenous populations, African Americans and women of Hispanic background.

Pregnancy and glucose metabolism

During the 2nd and 3rd trimesters of pregnancy, the insulin requirements of a pregnant woman are 2 to 3 times greater than normal. This could be explained by the gradual increase during pregnancy of the production of “anti-insulin” hormones (for example, placental hormones, cortisol and growth hormones), which reduce the effects of insulin on the body. They are essential for the good progress of a pregnancy, therefore for the health of the fetus and the mother. Normally, this insulin resistance stimulates the pancreas to make more insulin to compensate. However, in some women, the pancreas does not produce this excess insulin. In them, then settles an excessively high level of sugar in the blood, hyperglycemia.

Possible consequences

For the mother:

  • Hypertension and edema (preeclampsia).
  • spontaneous abortions
  • Urinary tract infection.
  • Delivery by cesarean section (in case of heavy weight of the child).
  • Premature delivery.
  • Type 2 diabetes after pregnancy.

For the child:

  • Weight exceeding 4 kg (9 lbs) at birth (macrosomia). This is the case for 17% to 29% of children born to mothers with gestational diabetes, compared to 5% to 10% for all mothers.
  • Neonatal hypoglycemia.
  • Exaggeration of jaundice of the newborn.
  • Respiratory distress syndrome.
  • Possibly developing diabetes, most often type 2. (It is suspected that gestational diabetes may lead to an increased risk of type 2 diabetes in the unborn child subsequently in adulthood due to ‘early exposure to a potentially harmful environment in the prenatal period).

After childbirth

In 90% of cases, gestational diabetes goes away within a few weeks of giving birth. However, gestational diabetes increases the risk of diabetes in women afterwards. Thus, a certain proportion of women with gestational diabetes suffer, a few months or several years later, from type 2 diabetes or, much more rarely, from type 1 diabetes.


Gestational diabetes is not a contraindication for breastfeeding. On the contrary, studies indicate that it may confer some protection against diabetes . This is all the more important since the children of mothers who have gestational diabetes are likely to be at greater risk of developing diabetes themselves.

Note. Women who know they are diabetic and want to have children must absolutely obtain a rigorous medical follow-up which must begin before conception.

Symptoms of gestational diabetes

As with other types of diabetes, a pregnant woman with gestational diabetes may not suffer from anything in particular (it is then said to be asymptomatic). In rare cases, she may have the following symptoms:

  • unusual fatigue for a pregnant woman;
  • profuse urination;
  • intense thirst.
  • weight loss or on the contrary very rapid weight gain.

Women most at risk of gestational diabetes:

  • Women of Hispanic (Latin American), Native American, African American or Southeast Asian descent.
  • Women 30 years of age and older.
  • women with a family history of diabetes.
  • Women who have a personal history of glucose intolerance or “prediabetes”.
  • Women who have had any of the following problems during a previous pregnancy: gestational diabetes, hypertension, recurrent urinary tract infection, hydramnios (excess amniotic fluid).
  • Women who have polycystic ovary syndrome.
  • Women who have ever had a baby weighing more than 4 kg (9 lbs) at birth (macrosomia).
  • Who who who suffer from obesity or who have undergone restrictive diets.

Risk factors of gestational diabetes

  • Overweight and obesity are important risk factors.
  • Taking oral corticosteroid drugs for a long time.

Prevention of gestational diabetes

Basic preventive measures

The best way to prevent diabetes during pregnancy is to maintain a healthy weight and adopt a healthy lifestyle (eat well, exercise regularly…) before getting pregnant.

In obese women, it would be wise to lose weight before pregnancy (without falling into the trap of restrictive diets) especially if there is a family history of diabetes or if the future mother has had repeated miscarriages. .


It is possible to screen for diabetes in early and during pregnancy. The aim is to prevent as much as possible any complications that may arise in mother and child. It is important to discuss screening with your doctor. The decision to screen or not depends on several factors, such as the pregnant woman’s state of health and the course of her previous pregnancies, if any. Her values ​​and risk tolerance also sometimes come into play.

There are different tests that can be used to screen for abnormally high blood sugar:

  • Induced hyperglycemia test (ingestion of 50 g to 75 g of glucose followed by a blood glucose reading 2 hours later).
  • Fasting blood sugar test.
  • Blood hemoglobin A1C test (normally only for women known to have diabetes), which helps estimate the average blood sugar level over the past 3 months.

1st trimester screening

Recommended for all pregnant women who have many risk factors for diabetes. The test takes place at the time of the 1st medical examination of the pregnancy follow-up. If the result is negative, another test is still suggested later in the pregnancy.

Screening between the 24th and 28th weeks of pregnancy

The International Diabetes Federation recommends it for all pregnant women. Women at very low risk for diabetes (Caucasian, under 25, thin, with no personal or family history of glucose intolerance) may be exempt, according to the American Diabetes Association.

Evolving practices

The experts are clear: it is essential to screen for gestational diabetes in the 1st trimester in women at risk. Diabetes (type 1 or type 2) that starts early in pregnancy means it was present before pregnancy, but was not yet declared or diagnosed. If the fetus is in contact from the first months with a diabetic environment, serious complications can ensue, such as congenital malformations or even sometimes fetal death.

Screening between the 24th and 28th weeks of pregnancy has long been reserved for pregnant women at risk of diabetes. The need to extend screening to all pregnant women has been widely debated. Indeed, the ability of treatment to prevent complications among this large population has not been clearly demonstrated. In addition, deciding to treat a pregnant woman requires a lot of caution. The treatment is mainly based on insulin which requires injections sometimes several times daily and daily.

However, recent data support the usefulness of routine screening. A major study published in 2008 and conducted among 25,505 women in 10 countries established a direct relationship between blood sugar between the 24th and 32nd weeks of pregnancy and certain perinatal complications in mother and child. In addition, reviews of studies published in 2009 and 2010 have highlighted the effectiveness of treatment for gestational diabetes in preventing several complications (it can, for example, reduce the risk of cesarean section), even when the diabetes is “mild”.

In light of these data, most specialists and expert groups now recommend routine screening. In practice, the advice may still vary from doctor to doctor and from case to case. When glucose intolerance or diabetes is detected, changes in diet and lifestyle are often sufficient to control blood sugar.

Treatment of gestational diabetes

A growing body of scientific evidence supports the effectiveness of treatment for gestational diabetes in reducing complications. The treatment is adapted on a case-by-case basis. A blood glucose meter is essential to check and correct if necessary the quality of blood sugar control.

Simple lifestyle changes

A few changes in diet and lifestyle are often enough to keep blood sugar at acceptable levels, and for mother and child to be well. For example, monitoring daily carbohydrate intake (sugars contained in particular in fruit juices, sodas, syrups, candies, fruits, jams, compotes) and eating less foods high in saturated fat (butter , cream, fat contained in fatty meats, cold cuts, palm oil, etc.) should help control a pregnant woman’s blood sugar level. The diet must of course respect the nutritional needs of the pregnant woman. Monitoring by a nutritionist and / or dietitian throughout pregnancy is also recommended.

Doctors are also emphasizing weight control in women with gestational diabetes. Weight gain during pregnancy should not be too great in order to preserve the health of the woman and her child as much as possible. The stronger the woman is at the start of pregnancy, the less weight she should gain.

The diet should be adapted to the profile of each pregnant woman and it should aim to optimize glycemic balance, reduce lipolysis source of ketone bodies. The proposed diet must cover the daily nutritional needs which are established overall at 1800-2000 Kcal/d, ideally divided into four minimum daily intakes including one at bedtime in order to reduce the night fasting period. Only the presence of obesity can encourage a further reduction in the daily calorie intake because the total weight gain at the end of pregnancy must, in this case, be as minimal as possible.

Insulin injections

Insulin is for women for whom lifestyle changes alone cannot control blood sugar. Most anti-diabetic drugs are contraindicated in pregnancy. Recent studies show metformin to be an effective alternative to insulin, and safe enough to offer it to pregnant women. However, insulin is still preferable to anti-diabetic drugs.

Note. Women who have had gestational diabetes are at higher risk for type 2 diabetes. More than half of them have it later in life. The treatment offered to control gestational diabetes also helps to maintain health for as long as possible. Encouragingly, women who have had gestational diabetes and who regain their normal weight after childbirth halve their risk of developing type 2 diabetes.

Important measure. Women who have had gestational diabetes would benefit from having their blood sugar checked regularly.

In conclusion

Pregnant women must become aware that they carry within them a living baby subjected to an environment which can affect in a lasting and profound way the baby’s health throughout life. The most influential factors are: stress and nutrition. The embryo, the fetus, then the baby will respond to a given perinatal environment perceived as beneficial or on the contrary as harmful, which may later determine the biology of the child when it becomes an adult.

We are talking about a metabolic footprint which is a very strong medical concept.

Treatment strategies adopted during pregnancy optimize the health and chances of survival of the child after birth. The expectant mother should not submit to restrictive diets during pregnancy. She also must not eat for 2 either as the collective imagination would make us believe. A pregnant woman must simply respect the classic hygieno-dietetic rules validated medically. For advices, see your doctor.

Elena Mars

Elena writes part-time for the Scientific Origin, focusing mostly on health-related issues.