Dr Rebecca Reynolds shares about Diabetes and pregnancy by highlighting the risks for mothers and babies
Diabetes is a global health problem affecting children and adults including women of child bearing age. Pregnant women with Diabetes can be broadly classified as those with pre-existing Diabetes (either type 1 or type 2) who have become pregnant and those who were diagnosed with Diabetes after becoming pregnant.
Pre-existing Diabetes and pregnancy:
Prior to conception all women with Type 1 and Type 2 Diabetes must be counselled about the effect of uncontrolled or high sugars on the maternal and fetal complications in pregnancy and also the effect of pregnancy on Diabetes and its related comorbidities (like hypertension, obesity) and complications (affecting eyes, kidneys and nerves called retinopathy, nephropathy and neuropathy respectively).
Glucose from the mother crosses the placenta to reach the baby’s blood for energy. Hence if mother’s blood glucose is high, it causes high blood glucose in the baby as well. Early in pregnancy, high sugar level can cause miscarriage and birth defects. As the new organs (organogenesis) of the foetus are primarily formed in the first 5- 8 weeks of pregnancy, good sugar control will prevent the development of abnormalities like microcephaly (small head), congenital heart problems, renal anomalies (abnormalities of kidney development) and prevent preterm delivery. Observational studies have shown that the increased risk of diabetic embryopathy (abnormalities in the developing embryo) was directly proportional to the elevations in A1 C. (A1C is a blood test , which reflects the average blood glucose in the previous 3 months.)
Persistent high glucose during pregnancy causes fetal pancreatic hyperplasia and excessive utero insulin secretion. Hence the neonates (babies) are prone for prolonged and severe hypoglycaemia ( low blood glucose) due to the continued high insulin secretion after delivery.
In the latter half of pregnancy, high sugar in the mother, will cause the size and weight of the baby to be larger than the average resulting in the complications during and after the delivery. Large babies may require caesarean section for delivery as vaginal birth will be difficult. Also, high sugars in the last half of pregnancy, increases the risk of developing pregnancy induced hypertension called pre-eclampsia. It is characterised by high blood pressure, fluid retention or oedema of the face and hands and spilling of protein in the urine (called proteinuria). Hence blood glucose control is very important especially in pregnancy to avoid complications to both mother and the baby
Women with pre-existing Diabetes, should be counselled about the development or progression of retinopathy. Diabetic retinopathy is one of the early complications of Diabetes caused by the damage to the blood vessels of the light sensitive tissue in the back of the eye called retina. Initially patient may by asymptomatic or have only mild vision problems. This risk is high in women with high HbA1c or whose HbA1C falls very rapidly. However, the impact of pregnancy on retinopathy is only temporary and the retina returns to the pre-pregnancy level in most women after few months of delivery.
As per ADA (American Diabetes Association) the recommended HbA1C target in pregnancy is < 6%, which is lower than the non-pregnant target level. Since there is an increased turnover of red blood cells during pregnancy, this target value of HbA1C is lower than non-pregnant HbA1C level. Self-monitored blood glucose readings (SMBG) using a reliable glucometer is essential all through the pregnancy to help with the management of Diabetes. The target of fasting blood glucose value is <95mg/dl, post-prandial after 1 hour is <140mg/dl and post- prandial after 2 hours is <120mg/dl. In pregnancy SMBG, for post-prandial testing is recommended after 1 hour of meals instead of 2 hours, because the glucose level is highest after 1 hour.
| Parameter | Target in pregnancy |
| Fasting blood glucose | 70-95 mg/dl |
| Post-prandial after 1 hour | 110-140 mg/dl |
| Post- prandial after 2 hours | 100-120 mg/dl |
Usually during pregnancy, high blood glucose (hyperglycaemia) occur due to the hyperglycaemic effect of placental hormones. In pregnant women without Diabetes, the pancreas is able to produce enough insulin to maintain normal blood glucoses. However, in women with Diabetes, treatment is adjusted to maintain the recommended blood glucose targets with insulin.
Other Preconception/ gestational care
Regular pre conception care including starting folic acid supplements and changing medications of co-morbid conditions like hypertension to medications which are safe in pregnancy must be done. Angiotensin convertase enzyme (ACE) inhibitors used for hypertension treatment must be changed to methyldopa and labetolol. Statins, used to treat elevated cholesterol are not safe in pregnancy, hence must be stopped. Women with type 1 or type 2 Diabetes should be prescribed low dose aspirin 150mg, starting at 12 to 16 weeks of pregnancy to lower the risk of pre-eclampsia.
Gestational Diabetes
Diabetes diagnosed at 24 weeks of pregnancy (gestation), in women not known to have Diabetes, is called Gestational Diabetes. It is usually confirmed with oral glucose tolerance test (OGTT),where in fasting blood glucose (ideally about 8 hours of overnight fasting) and then 1 hour and 2 hours post drinking 75 g of oral glucose are measured.
Diagnosis of gestational diabetes at 24-28 weeks of pregnancy, using Oral glucose tolerance test (OGTT)
|
Pre-existing Diabetes treatment during pregnancy
Since women with Type 1 Diabetes are already treated with insulin, pregnancy safe insulin Detemir is used to control the basal (in between meals) blood glucose. For bolous insulin which controls the post meal elevation in sugars, short acting insulin like Aspart is used three times a day with meals.
The requirement of insulin dose is reduced to 50 per cent following delivery of the baby. Hence the mother should be monitored closely for hypoglycaemia and insulin dose adjusted accordingly.
Pre-existing Type 2 Diabetes treatment during pregnancy
Type 2 Diabetes is usually treated with oral anti-diabetic medications. However, since these medications are not safe in pregnancy, the patient should be shifted to insulin. Similar to type 1 Diabetes management, in pregnancy, long-acting basal insulin Inj. Detemir safe in pregnancy is used to control the in between meals sugar. It is initially started once a day and then increased to maximum of twice a day. The post-meal rise in sugar is controlled with bolus insulin given in the form of short acting insulin like Inj. Aspart, three times a day before the meals.
After delivery the requirement of insulin decreases considerably, and the anti- diabetic medications especially metformin, the first line oral agent can be restarted safely. The two anti-diabetic medications, which are safe in pregnancy are metformin and glyburide. However, they are known to cross the placenta and reach the baby.
These medicines are secreted in the breast milk in small quantities as well during breast feeding. Hence the baby should be monitored for hypoglycaemia.
Diagnosis of type 2 diabetes following delivery: Using oral glucose tolerance test (OGTT)
| Parameter | Normal values | Pre -diabetes | Type 2 diabetes |
| Fasting blood glucose | <100 mg/dl | –
100 12 5 mg/dl |
= 126 mg/dl |
| 2 hours after consumption of 75g of glucose | <140 m/dl | 140 -199 mg/dl | e 200 mg/dl |
Gestational Diabetes treatment
Depending on the blood glucose level, a trial of diet and exercise can be given for a week, if the sugars are still uncontrolled, then insulin can be started just like in pregnant females with pre-existing Diabetes. After delivery usually the insulin requirement totally resolves, hence the anti-diabetic treatment should be stopped for 24 to 72 hours. Glucose levels are
monitored. If glucose level remains normal, Oral glucose tolerance test can be done in 4 -12 weeks following delivery, to confirm the resolution of gestational Diabetes. The criteria used for diagnosis of Type 2 Diabetes, after delivery is similar to regular Type 2 Diabetes and is not the one used in pregnancy, (as shown above). If there is elevation in blood glucose levels, oral metformin can be started and dose adjusted to maintain normal blood glucose levels.
Thus, generally a complete resolution of
Diabetes occurs in most gestational Diabetes, only to recur after about 5 years.
In conclusion, Diabetes care in pregnancy starts with preconception care which includes proper counselling and education, screening for other conditions like thyroid and continues with good blood glucose control all through the pregnancy, labour, delivery and
post-partum (post-delivery) period for the best outcome of pregnancy and the offspring.
