Diabetes is usually a disease of later life, which may account for the low incidence of this in pregnancy. However, diabetes may also occur in the younger age group (juvenile diabetes), and this needs insulin for control. The younger patienty are rather thin, and the tendency for ketosis is more are ked. In the folder age group the patients are ally obese, the tendency for testist less and usuamilder variety can be controlled with diet and exercise. complication
CLASSIFICATION OF DIABETES IN PREGNANCY
In pregnancy, the diabetes can be grouped into two categories:
1) Overt diabetes: This is seen in women known to be diabetic before the onset of pregnancy. Most often they are insulin dependent (IDDM), though some times they may be non-insulin dependent (NIDDM).
2) Gestational diabetes: This diagnosis is made when diabetes is detected in the course of the pregnancy and is defined as carbohydrate intolerance of variable severity first diagnosed during pregnancy.
EFFECTS OF PREGNANCY ON DIABETES
Normally, pregnancy induces a diabetogenic response in the individual, as the insulin requirements during pregnancy are increased .It starts from the third month and continues till term. Among the reasons given for this increase are the very large increase in insulin antagonising hormones like human 1 placental lactogen, progesterone, and cortisol, and also the production of enzymes (placental insulinase) by the placenta that increase the degradation of insulin. Unless a patient is carefully watched during pregnancy, ketosis is likely to develop more easily because of the constantly changing insulin requirements.
There is often a lowered renal threshold in pregnancy which is more common in diabetics; it clears up in the puerperium. This lowered renal threshold makes repeated blood sugar estimation imperative in the control of diabetes in pregnancy. Retinal changes, if present, may be aggravated during pregnancy.
Effect of Diabetes on Pregnancy
Good medical and obstetric care throughout pregnancy, labour and puerperium usually results in a favourable outcome. However, the following complications have been seen in diabetic pregnancies.
Abortion: There is an increased fisk of abortion in patients with uncontrolled diabetes
Fetal malformations: The incidence of major malformations is increased in overt diabetics. Cardiac and neural tube defects are commonly seen.
Preterm delivery: Overt diabetics antedating pregnancy is a risk factor of preterm delivery.
Pregnancy induced hypertension: Diabetic women are more prone to develop PIH
Fetal macrosomia: This is particularly seen in uncontrolled diabetics and is thought be due to an increase in body fat mass. Maternal hyperglycemia) results in fetal hyperglycemia resulting in fetal hyperinsulinemia, which in turn stimulates excessive somatic growth.
Hydramnios: In the uncontrolled diabetic women, hydramnios is often seen. This may be due to the Flarge placenta, fetal malformation or fetal polyuria secondary to fetal hyperglycemia.
Maternal infections: A pregnant diabetic mother is more prone to urinary tract infection and monilial vulvovaginitis
Unexplained fetal death: Still births without identifiable causes are a phenomenon peculiar to pregnancies complicated by overt diabetes
DIAGNOSIS OF GESTATIONAL DIABETES
There are some women who have an increased risk of developing diabetes during pregnancy. These women need to be identified and managed to have a favourable outcome. For identification of these women, screening tests become essential.
SCREENING TEST FOR DIABETES
Screening test for gestational diabetes should be performed between 24 and 28 weeks of pregnancy in those women not known to have glucose intolerance earlier in pregnancy. Plasma glucose is measured one hour after a 50 g glucose load without regard to the time of the day or the last meal. A value of 140 mg/dl or higher will identify 80% of women with gestational diabetes.
GLUCOSE TOLERANCE TEST (GTT)
This is done when the screening test is positive or if the index of suspicion is very high and one does not want to do a two step procedure (screening and then GTT). The oral GTT is the one usually preferred. The pregnant woman is instructed to take a normal diet the previous day. A fasting blood sample is taken for glucose estimation. The patient is then given 100 g of glucose in 200 ml of water orally. Venous blood samples are collected at the end of 1 hour, 2 hours and 3 hours. A normal GTT is one when the fasting level is 105_mg/dl or less, 1 hour value is 190 mg/dl, 2 hours value is 165 mg/dl, and 3 hours value is 145 mg/dl. GTT is diagnosed if any two values are higher than normal.
RISK FACTORS FOR SCREENING FOR GESTATIONAL DIABETES
There are certain features that a woman may have in her family or medical or obstetric history that predispose her to an increased possibility of developing diabetes in pregnancy. These are:
Diabetes in a first degree relative
Maternal obesity (>120% ideal body weight).
Previous large baby (>4 kg)
Previous unexplained stillbirths.
Previous abnormal glucose tolerance test.
Hydramnios or macrosomia in the present pregnancy
MANAGEMENT White's classification of diabetes in pregnant women gives a good working guide to patient management.
Principles of management include control of diabetes, obstetric management and timing of delivery and specialised care for the newborn. These could be discussed under the following headings.
ANTENATAL CARE: Control of blood sugar: Optimum management of diabetes in pregnancy will be maintain fasting level of <95 mg/dl and postprandial levels of <140 mg/dl and <120 mg/dl at 1 and 2 hours, respectively. In overt diabetes it is difficult to achieve this goal. In these patients, diabetes tends to be unstable in the first trimester due to nausea and vomiting associated with pregnancy. Some overt diabetics may need to be hospitalised to achieve good control. There is an increase in insulin requirement from about 24 weeks onwards. Hence close monitoring of blood sugar is essential. Depending on the quality of control, blood sugar needs to be estimated at 2-3 weeks interval.
Optimum control of blood sugar can be achieved by diet alone or diet along with insulin injections.
1) Diet in pregnant diabetics: A total caloric intake 55.1 of 30-35 kcal/kg of ideal body weight is given as three meals and three snacks daily. An ideal →10f dietary composition - is 55% carbohydrate, 20% protein and 25% fat with less than 10% saturated fat.
2) Insulin: If the postprandial blood sugar levels remain above 150 mg/dl in spite of dietary regulation, plain insulin is administered subcutaneously in three divided doses before breakfast, lunch and dinner. The amount of insulin required will depend on the blood sugar levels. The insulin levels are gradually increased until optimum control is achieved. At times, a combination of of plain and lente insulin may be required.
3) If overt diabetics have been controlled on oral hypoglycemic agents prior to pregnancy, it is better to switch to insulin therapy once pregnancy is confirmed since oral hypoglycemic agent may cause fetal defects
PREPREGNANCY COUNSELLING IN OVERT DIABETES
To prevent pregnancy loss as well as congenital malformations in infants of diabetic mothers, optimal medical care and patient education are recommended. These include:
■ Baseline glucose control and end organ damage should be assessed to include renal function and retinopathy.
■ Glycosylated hemoglobin should be estimated to check the control of sugar for the past 4 to 8 weeks.
■ Folic acid supplementation should be given.