Gestational Diabetes Mellitus is a condition in which a pregnant woman exhibits high blood-sugar during the third trimester of her pregnancy. It is a temporary condition that goes away after childbirth. However, depending on the severity of the condition, it can have long-term consequences for both the mother and child. That is why, Gestational Diabetes Mellitus or GDM should not be taken lightly and every woman who is pregnant or planning a pregnancy should be completely aware of this condition.

Causes

Why some pregnant women develop GDM while some do not is still not clear. But this is the mechanism of the condition. Hormonal changes in the mother’s body are natural during pregnancy. The placenta is an organ that develops in the uterus during pregnancy. It nourishes the fetus by providing oxygen and nutrients, and removes waste products from the baby’s blood. Further, the placenta secretes a variety of hormones that aid in development of the baby. Some of the placental hormones include prolactin, neuroactive hormones, growth hormone and steroid hormones.

The placental hormones have an effect of blocking insulin action in the woman’s body. The mother’s body is not able to generate enough insulin (like type-1 diabetes) or make use of the secreted insulin (like type-2 diabetes). She develops insulin resistance, as a result of which, glucose in her blood cannot be efficiently converted to energy. Glucose starts accumulating in the blood, leading to hyperglycemia or high blood-sugar.

Risk Factors for GDM

• Obesity or being overweight as this interferes with hormone production or hormone action
• Being sedentary or physically inactive during term. This again affects metabolism, hormone production and aids weight-gain.
• Having prediabetes, a condition in which the blood-sugar levels are high but not high enough to trigger type-2 diabetes.
• Having suffered from GDM during the previous pregnancy
• Currently suffering from polycystic ovarian syndrome/disease (PCOS/PCOD)
• Genetic: one or more close family members are diabetic
• Having delivered a baby weighing more than 9 pounds or 4.1 kgs during the previous pregnancy
• Ethnicity: Blacks, Hispanics, Asian Americans and American Indian women are more at risk of GDM than white Caucasian or Asian women.

Also Read: Common causes of Neonatal and Infant deaths in India

Consequences to the baby

• Macrosomia or ‘fat baby’: As explained before, the mother’s blood is high in glucose levels. This extra blood-glucose penetrates the placenta and reaches the baby’s blood. The baby’s pancreas now makes extra insulin to process the extra blood-glucose. Since the baby is getting more glucose than it requires for its growth or development, the extra glucose is stored as fat in the body, making the baby heavier than what a healthy mother would be carrying.
• Shoulder dystocia and birth trauma (birthing injuries): The larger baby means, at the time of delivery, the shoulders of the baby can get stuck in the pelvic bone of the mother. This causes fracture in the baby’s collarbone or fracture in its arm, injuries to nerves in the brachial plexus, and bleeding (post-partum hemorrhage).
• Hypoglycemia: Because the baby’s pancreas is making all the extra insulin to process the extra glucose, the baby is born with low blood sugar. This results in irritability, tiredness and seizures in the baby.
• Respiratory issues such as Respiratory Distress Syndrome: This is because babies born of mothers with GDM may not have enough of a protein called surfactant in the lungs. This protein prevents the alveoli in the lungs from collapsing and thereby holding as much oxygen as possible.
• Jaundice: This is because the baby’s liver isn’t fully developed. Similar to adult jaundice, a newborn with jaundice has yellowish skin and yellow eyes.
• Electrolyte imbalance: Due to the high levels of blood glucose in the baby, it can suffer from hypocalcemia or hypomagnesemia (low levels of calcium and magnesium in the blood, respectively). The baby may have seizures, be irritable and the parathyroid hormone may not be synthesized in time.
• Congenital malformations: The baby is at a high risk of birth defects such as spina bifida (spine and spinal cord are not formed properly), anencephaly (a large part of the skull and cerebral hemispheres are absent) and caudal dysplasia (poor or failed development of some of the vertebrae).
• Obesity and type-2 diabetes as adults.

Consequences to the mother

• Loss of the infant: There is a high likelihood of a miscarriage or the baby being born dead (stillbirth).
• Premature birth or preterm baby: The baby is born before week 37 of pregnancy. The baby has a less developed liver and lungs compared to a full-term baby, so the risk of jaundice and respiratory issues goes up.
• C-section deliveries: There is a high likelihood that the mother will not have a normal childbirth and will require a caesarean.
• Hypoglycemia: Since the mother is constantly taking insulin due to GDM, it can suddenly cause low blood-sugar or hypoglycemia, soon after childbirth.
• Pre-eclampsia or hypertension: Women with GDM have a higher risk of developing hypertension or high BP than healthy pregnant women. Pre-eclampsia can harm both the baby and the mother. The baby is born premature, and hence suffers many complications. The mother can suffer from seizures or stroke due to a blood-clot or bleeding (hemorrhage) in the brain.
• Post-partum depression: Many women experience a sense of loss and depression soon after childbirth, which goes away after a few weeks. They lose interest in everything including their newborn. Women with GDM are at higher risk of such a depression than healthy mothers.
• Developing type-2 diabetes at a later stage in life.

Diagnosis of GDM

Doctors are well-aware of the likelihood of GDM. That is why, the consulting gynecologist will educate the pregnant lady on signs and symptoms of GDM to look out for. She would also screen the mother for GDM risk by looking at the family history of diabetes, and the weight of the lady. Based on these parameters, the gynecologist may call for a blood-sugar screening in the 2nd trimester of pregnancy. Thereafter, there will be routine blood-sugar tests which include:

• Initial glucose Challenge test: In this, the lady must drink a sweet solution, and the blood-sugar levels are monitored one hour later. In case GDM is suspected, the next test is conducted a couple of days later.
• Follow-up glucose Tolerance test: Here again, the lady will drink the sweet solution which now has more sugar than previously. Then after every 1 hour, a blood-sugar reading is taken for up to 3 hours. The reading will confirm or rule out GDM.

Also Read: Is it possible to reverse diabetes?

Treatment of GDM

Treating GDM involves lifestyle changes which includes staying active and consuming a healthy diet rich in fiber and whole grains, low in sugar and salt, and moderate on fat. Blood sugar must be monitored 5 times a day every day. If none of these are working, then the doctor may prescribe oral medicines or insulin shots as relevant.

Outlook

As is evident, Gestational Diabetes Mellitus is quite serious, with long-term consequences to both mother and child. If you are a pregnant woman or planning a pregnancy, please remember to follow all the instructions and advice of your consulting gynecologist. They are not mere lip-service but real tips to prevent any health condition occurring during the term of pregnancy. This will go a long way in ensuring a healthy, full-term pregnancy, and long-term health for both you and your baby.

Reviewed by Dr Suresh S Venkita, Group Medical Director, Kauvery Hospitals

Kauvery Hospital is globally known for its multidisciplinary services at all its Centers of Excellence, and for its comprehensive, Avant-Grade technology, especially in diagnostics and remedial care in heart diseases, transplantation, vascular and neurosciences medicine. Located in the heart of Trichy (Tennur, Royal Road and Alexandria Road (Cantonment), Chennai, Hosur, Salem, Tirunelveli and Bengaluru, the hospital also renders adult and pediatric trauma care.

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