What is Diabetes Mellitus?

Gestational Diabetes – Can be detected and controlled.

Gestational Diabetes or GDM (Gestational Diabetes Mellitus) is a condition in pregnant women, without a previous history of diabetes, exhibiting high blood glucose levels.

Though it can occur at any time, it usually manifests itself during the third trimester of pregnancy.

The body does not secrete the excess insulin required during pregnancy and this causes the blood sugar levels to rise.

Though gestational diabetes has a few symptoms, it is detected during general screening during pregnancy and effects about 3 to 10% of pregnant women.

Though there are risk factors, to the mother and fetus, associated with gestational diabetes, it can be controlled and kept within safe margins.

Types of Gestational Diabetes:

The problem with gestational diabetes is that it is largely symptomless and is usually detected only through screening.  There are two types of gestational diabetes.

Type A1 has abnormal oral glucose tolerance test or OGTT, but sugar levels are normal fasting and two hours after meals.

In Type A2, there is abnormal OGTT coupled with abnormal glucose levels during fasting and postprandial.  In Type A1 diet modification is sufficient to control the glucose levels and keep it within acceptable limits.

In Type A2, in addition to diet modification, therapy in the form of insulin or other medication may be required.

In addition to these two types of gestational diabetes, there is a second group consisting of women who had a history of diabetes prior to the pregnancy.  This too has different subtypes.

Risk factors for developing gestational diabetes:

•                A previous history of gestational diabetes or impaired glucose tolerance.

•                Having a close relative with type 2 diabetes.

•                Maternal age: the risk increases with the age of the pregnant women, especially >35 years.

•                Some ethnic groups such as Afro-Americans, Afro-Caribbean’s, Native Americans, Hispanics,
Pacific Islanders and South Asians show a higher predisposition to gestational diabetes.  The
risk factor increases between 2.1 to 8.6 times.

•                A history of childbirth with the baby having a high birth weight.

•                A problematic obstetric history.

•                Women who smoke run a double risk in developing gestational diabetes.

•                Women who have Polycystic Ovarian syndrome.

What is the criterion for screening pregnant women for gestational diabetes?

About 40 to 60% of women who develop gestational diabetes have no demonstrable risk factor and due to this reason, the medical fraternity is in favor of all pregnant women being screened.  Additionally, most women do not exhibit symptoms of gestational diabetes and this too is in favor of 100% screening of pregnant women.  Some women do exhibit symptoms such as thirst, increased frequency of urination, exhaustion etc., but they are few in number.

There are a number of screening tests prescribed to detect gestational diabetes.  For low risk category of patients, a two step approach is prescribed.

If the initial screening test shows a suspicious result, then a diagnostic test can be done.

In women with high risk factors, a diagnostic test is done in the first antenatal check-up.

The types of diagnostic tests done to detect gestational diabetes are: Fasting glucose test, 2 hour postprandial glucose test, random glucose test, OGTT etc.

At what sugar level is gestational diabetes confirmed?

The screening glucose challenge test is performed between 24 and 28 weeks of pregnancy.  It requires the patient to drink 50 grams of glucose solution and taking blood sugar levels after one hour.

At a cut off level of 140 mg/dl, 80% of women having gestational diabetes can be detected and this is an acceptable level of detection.

Lowering this value may detect a higher percentage of women with gestational diabetes, but will needlessly subject more women to an OGTT.

The OGTT is carried out in the morning after fasting between 8 to 14 hours.  For the three days prior to the test, the patient can have unrestricted diet which contains at least 150g of carbohydrate/day along with unlimited physical activity.

After taking 100 g of glucose blood sugar readings are taken when fasting and at hourly intervals for three hours.  The abnormal levels as per the American Diabetics Association are:

•                Fasting blood glucose level >/=   95 mg/dl.

•                1 hours blood glucose level >/= 180 mg/dl.

•                2 hours blood glucose level >/= 155 mg/dl.

•                1 hours blood glucose level >/= 140 mg/dl.

What are the risks to the baby due to gestational diabetes?

•                Growth abnormalities in baby.  The baby can either be large or small for gestational age.

•                Chemical imbalance which may require neonatal intensive care.

•                May have a complicated birth process.

•                The baby may suffer from hyperglycemia, jaundice etc.

Women who suffer from gestational diabetes need not be unduly worried.  In a vast majority of the women, the pregnancy proceeds without any problem.

Under the care and guidance of a Doctor, the effects of gestational diabetes can be controlled and risk factors minimized.