Initiate Insulin therapy if nutrition therapy and exercise failed to achieve blood glucose goals for women with gestational diabetes.
Before the advent of insulin in 1922, pregnancy was associated with a >90% infant mortality rate and a 30% maternal mortality rate.
For gestational diabetes, the timely initiation of insulin treatment to maintain proper blood glucose level. The pre-prandial glucose levels less than 90 mg/dl, and postprandial glucose levels less than 120 mg/dl has reduced the risks of fetal and maternal complications.
Insulin Therapy for Gestational Diabetes
Gestational diabetes needs insulin therapy if Medical Nutrition Therapy failed to achieve a 2-hour postprandial glucose level of less than 120 mg/dl.
Some with gestational diabetes need insulin to reach their blood glucose targets. Insulin is not harmful to your baby, but high blood sugar level is toxic. So If you are unable to achieve your target blood glucose level, then you should make it with insulin therapy.
Prefer insulin over oral medicine for gestational diabetes
Most doctors consider the oral medication for gestational diabetes treatment is not safe and thus they prefer insulin therapy.
Most of the diabetes oral medications can cross the placenta and may affect your baby. They can make the fetus to secrete excess insulin and leads to severe hypoglycemia (low blood glucose). Additionally, oral drugs are not sufficient enough to fulfill the rising insulin requirements of pregnancy. However, insulin does not cross the placenta but can be able to meet the excess insulin requirement during pregnancy.
However, recently, doctors have prescribing glyburide and metformin to gestational diabetes patients. The FDA has not approved both of these drugs to treat gestational diabetes. Glyburide is the only medication well studied in pregnant women.
Insulin therapy
Up to 50 % of women with gestational diabetes will need insulin injections during pregnancy to maintain normal blood glucose levels.
Insulin treatment for women with gestational diabetes is to lower blood glucose levels to reach a normal range and to avoid pregnancy complications.
Insulin can be administered using an insulin pen, a syringe, or a needle. Usually, insulin therapy starts with a small dose of insulin and gradually increase until the blood glucose reached the normal range. This process varies from person to person.
What type of insulin is suitable for gestational diabetes?
There are different types of insulin available in the market, which last for a different length of time.
Human insulin treatment has been reported to achieve improved pregnancy and infant outcome compared with using highly purified animal insulin. Ref: American Journal of Obstetrics & Gynecology 167:1325–1330, 1992.
Human and highly purified insulin is significantly less immunogenic than mixed beef-pork insulin. Diabetes 37:276–280, 1988 & Diabetes 45:1750–1754, 1996.
Insulin & Insulin Analogs | |||
Insulin | Onset of action (in minutes) | Time to peak (in minutes) | The maximum duration of action (in hours) |
Regular insulin | 30 to 60 | 90 to 120 | 5 to 12 |
Insulin lispro (Humalog) | 10 to 15 | 30 to 60 | 3 to 4 |
Insulin Aspart | 10 to 15 | 40 to 50 | 3 to 5 |
Insulin glulisine | 10 to 15 | 55 | 3 to 5 |
NPH insulin | 60 to 120 | 240 to 480 | 10 to 50 |
Insulin glargine | 60 to 120 | None | 24 |
Insulin Detemir | 60 to 120 | None | 20 |
The rapid-acting insulin analogs are effective in normalizing blood sugar during pregnancy than human regular insulin. Also, a safety profile with a lower incidence of neonatal complications. The initial dose of insulin could be as low as four units and adjusting the dose of insulin to follow up.
Calculation of Insulin Dose
Women's weight in pounds / 2.2 = Women's weight in kilogram.
Weight in kilograms x k = total insulin requirement
k = 0.7, 0.8, and 0.9 for first, second, and third trimesters respectively.
50% of the total insulin requirement = daily basal insulin dosage provided by long-acting insulin.
Administered before breakfast (8:00 A.M.), before lunch (noon), and before supper (4:00 P.M.)
Initial Insulin Dose | |
Postprandial plasma glucose | Premixed Insulin dose |
More than 200 mg/dL | 8 units |
In-between 160 to 200 mg/dL | 6 units |
In-between 120 to 160 mg/dL | 4 units |
Some gestational diabetes patients may require a combination of short and intermediate-acting insulin in the morning and evening. If a patient has elevated blood sugar before lunch, then regular insulin is necessary for the morning to control the post-breakfast hyperglycemia. This regimen of regular and intermediate-acting insulin in the morning controls hyperglycemia in most cases.
If the blood sugar is high after dinner, then you may require a small dose of regular insulin before dinner alone with the regular and intermediate-acting insulin given in the morning. If the fasting blood sugar is high, then you may require a combination of regular and intermediate-acting insulin before dinner.
In this insulin regimen, give 2/3 of the total daily insulin in the morning and 1/3 in the evening. For this, a combination of 1/3 dose of regular insulin and 2/3 dose of intermediate-acting insulin is preferable. If the patient continues to experience high fasting blood glucose, then give intermediate-acting insulin at bedtime instead of before dinner.
The site of Insulin Injection
- A front/Lateral aspect of the thigh or over the abdomen
- Give insulin injection subcutaneously only.