The blood sugar curve in pregnancy

Any pregnant woman can have an abnormal increase in blood sugar which could also affect her health and, in some rare cases, even that of the baby.
Glycemic screening tests are used to ascertain these possible alterations of their metabolism.


Gestational diabetes mellitus GDM (acronym for Gestational Diabetes Mellitus) is a metabolic disorder characterized by glucose intolerance diagnosed for the first time during a pregnancy, which resolves after delivery in most cases, but which if not adequately treated treated involves complications for both the mother and the fetus. (Higher Institute of Health).

It is a type of diabetes that generally occurs after the fifth / sixth month of pregnancy. Although it requires constant monitoring, it should not worry excessively as it can be easily kept under control in order to avoid possible consequences.

Since undiagnosed diabetes can have negative consequences for the health of the woman and her baby, the following two tests are done in order to assist pregnant women who are at risk. They are quite similar in how they are performed.

  1. The glycemic curve test in pregnancy GCT (acronym of Glucose Challenge Test ) for the screening of gestational diabetes: the glycemic curve in pregnancy is used precisely to ascertain the existence of altered glycemic values.
  2. The oral glucose load test OGTT (acronym of _Oral Glucose Tolerance Tes_t) for its  diagnosis and screening.

The GTC test: the glycemic curve

The glycemic load  (CG) is a parameter that takes into account the quality and quantity of carbohydrates eaten.

The GCT glycemic curve test serves to ascertain alterations in carbohydrate metabolism in order to diagnose (or exclude the presence of) gestational diabetes  , a condition which, as we have said, must be monitored to safeguard the health of the mother and child. fetus.

When the glycemic curve is prescribed to the pregnant woman

The glycemic curve is a screening that is prescribed to pregnant women starting from the second trimester of pregnancy  to check for the possible onset of an abnormal glycemic level.

It is especially recommended for women

  • who are overweight,
  • to those who tend to be obese,
  • to those who have already had glycemic problems during pregnancy in the past,
  • with other risk factors, including their age (over 25/30 it is much easier to develop diabetes), and a proven presence of diabetes in the family,
  • who have considerable weight gain during pregnancy – including the fetus.

However, it can be said that there are no women who are completely free from risk factors for gestational diabetes. For this reason it is advisable that, after the fifth month, all women always undergo this test. The glycemic curve test is carried out in the morning: with the foresight of a balanced diet in the previous days.

The Oral Glucose Tolerance Test (OGTT )

The execution methods of the oral load test (OGTT) – with 75 g of glucose – can be summarized as follows:

  • In the days preceding the test, the woman must do normal physical activity.
  • The woman must eat normally in the days preceding the test (assuming at least 150 g of carbohydrates per day).
  • This test is usually done in the morning after fasting for at least 8/12 hours.
  • During the test the woman will have to sit or lie down without smoking or eating.
  • The OGTT with 75 grams of glucose for the determination of blood glucose on plasma must be performed with venous sampling at times 0′, 60′ and 120′.

For the  diagnosis of gestational diabetes mellitus, with OGTT 75 g it is sufficient that only one of the following three maximum glucose reference values ​​– indicated in the table below – is above the established limit.

Plasma blood sugar, Mg/dl Mmol/l

  • fasting: 92 5.1
  • after 1 hour: 180 10.0
  • after 2 hours: 153 8.5

However, it must be said that – according to the new Guidelines for the screening and diagnosis of gestational diabetes of The HAPO Study Cooperative Research Group – the procedure that was previously used in two phases (“mini-carbohydrate ” + OGTT in cases of positive miniload).

Indeed, according to the same Research Group, regardless of the presence of any risk factors for gestational diabetes, between the 24th and 28th week of gestation, all pregnant women who on the first visit have a fasting blood sugar lower than 92 mg/dl and have not previous diagnoses of manifest diabetes, should have an oral glucose challenge (OGTT).

The postpartum control test

For women with gestational diabetes, 8-12 weeks after delivery, glucose tolerance will be reassessed using OGTT 75 g.

The methods of carrying out the test, and the interpretative criteria are the same as usually used for non-pregnant people.

While during pregnancy it is possible to control gestational diabetes  with some simple measures that tend to promote a healthy lifestyle, it generally disappears shortly after childbirth.

Katherine Johnson, M.D., is a board-certified obstetrician-gynecologist with clinical expertise in general obstetrics and gynecology, family planning, women’s health, and gynecology.

She is affiliated with the Obstetrics and Gynecology division at an undisclosed healthcare institution and the online platform,

Leave a Reply

Your email address will not be published. Required fields are marked *