Diabetes means there is an increase in blood sugar levels i.e. hyperglycemia either due to lack of insulin or a diminished effectiveness of insulin, which is produced by the pancreas. Lack of insulin prevents the smooth uptake of glucose by the cells for the energy production, thus the glucose gets more and more accumulated in blood instead of going into the cells.
Diabetes is the most common complication of pregnancy affecting 1% of all pregnant women. Pregnant diabetic patients can be separated into two categories.
1 Overt diabetes – Patients are known to have diabetes before pregnancy.
2 Gestational diabetes – Patients are diagnosed as diabetic for the first time only during pregnancy.
Gestational diabetes (GD) or Pregnancy induced glucose intolerance; means that diabetes was induced due to pregnancy and it persists with remissions after delivery usually within six weeks. Quite a few pregnant women may have had diabetes but it was never recognised. Gestational diabetes is typically a disorder of late pregnancy so an increase blood sugar rate during the first trimester usually means diabetes was present even before conception. Patients are usually detected when their random blood sugar is more than 200mg/dl, with fasting blood sugar exceeding 110 mg/dl.
Women more prone to it
• Family history of diabetes in parents, siblings, and grand parents.
• Previous birth weight more than 4kgs
• Previous stillbirths.
• Previous unexplained foetal loss.
• Persistent glycosuria.
• Age more than 30yrs.
Pregnancy is said to be diabetogenic that is pregnancy induces glucose intolerance because of the exaggerated physiological changes in carbohydrate metabolism. As a result of complex endocrinal changes occurring during pregnancy there is an increased absorption of glucose from the intestinal tract but a delay in exchange of glucose between the blood and tissues.
Due to impaired insulin affect the blood sugar levels remain relatively high for nearly two hours following carbohydrate ingestion as compared to a non-pregnant state. Infact this facilitates the transfer of glucose from the maternal to foetal circulation. But when this mechanism becomes exaggerated it results in GD. As the pregnancy progresses and due to the various body changes there is increased filtration of glucose into the urine but decreased re-absorption of glucose.
Sugar tests during pregnancy
Investigations thus start at the first antenatal visit itself. Urine is examined as a routine for the presence of sugar. Positive test for glucose in urine is a common occurrence in random samples but it may be also due to presence of lactose or other such reducing substances. The commercially available dipstick detects this sugar while avoiding positive reaction for lactose.
Once urine sugar is detected it warrants further investigations, which is the 3hrs Glucose tolerance test (GTT) using 100gms of glucose. It is performed after an overnight fasting. The previous 3 days patient should have her normal meals with adequate carbohydrates rather than avoiding it before going for the test.
Patient is given 100gms of glucose with 200ml of water or limejuice. Blood and urine is collected in the fasting state and than at 1st hr, 2nd hr, 3rd hr. after the glucose load. The values should be less than
• Fasting-105mg/dl of glucose in blood.
• 1st hr – 190mg/dl
• 2nd hr—165mg/dl
• 3rd hr— 145mg/dl
If any two or more values are met or exceeded Gestational diabetes is diagnosed.
If the fasting blood sugar is 130mg/ dl without the glucose load there is no need to perform GTT to confirm the diagnosis, as it may be dangerous to overload the patient with glucose. GTT is done for all women with risk factors for GD, and or women with a positive screening test.
Patients with GD need more frequent antenatal supervision. A diabetic diet is the key to treatment; it is necessary that blood sugar levels be maintained. The diet should be nutritious for the mother and the baby. However dieting or starvation should be avoided. The average daily requirement for pregnant diabetic women is 1800-2000 calories.
The dietary restriction includes ice creams, chocolate, sweetened drinks, alcohol, Potato chips, fried food, all junk food, mangoes, and grapes. With diet restrictions fasting blood sugar should be maintained below 105mg/dl.
If the dietary management does not control the blood sugars then insulin is started. It is usually started with hospitalisation to safely adjust the dose and educate the women on self-administration. Frequent blood sugar estimation is required to control the insulin dose, as urine sugar examination is not very informative to adjust the insulin dosage. The insulin dosage is so adjusted that it maintains maternal blood glucose levels and at the same time prevent neonatal hypoglycemia. Oral anti diabetic medicines are not given as they may have an adverse effect on the foetus.
To the mother:
• Uncontrolled diabetes can cause spontaneous abortions.
• Increased incidence of excess water in the womb.
• Increased incidence of urinary tract infections.
• Complicated labour.
• Pre eclampsia
• Post partum hemorrhage i.e. excessive blood loss after delivery.
• Increase chances of sepsis, infections in the peurperium i.e. after delivery.
• Failing lactation.
To the baby:
• Increased incidence of large over weight baby more than 4kg. This causes difficult or obstructed labour, increase rate of caesarean section.
• 3-4 folds increase in congenital malformation specially related to severity of diabetes affecting organ formation in the first three months of pregnancy.
Women with overt diabetes are more at risk than those with GD for Congenital malformations, foetal deaths and stillbirths. Therefore good control of diabetes before conception and after reduces the incidence of complications. During the routine scans and ultrasounds, foetal abnormalities can be detected and appropriately looked into.
If the patient is young, under good diabetic control and without any obstetrical complications then the pregnancy can be continued the expected date of delivery. Caesarean section is done if labor is prolonged
Such babies can be more prone to neonatal complications like jaundice, respiratory distress syndrome so special neonatal care should be given.
If the mum is breastfeeding she is not given oral medicines of diabetes. Recurrence of GD in subsequent pregnancy was found in 20 women out of 30. Obese women are more likely to develop GD again. So, pre-pregnancy counselling before the next pregnancy is a good idea.