Ans. is c i.e. Insulin resistance improves with pregnancy In pregnancy, the insulin sensitivity decreases i.e. insulin resistance increases as the gestation advances mainly due to anti insulin signals produced by placenta (mainly human placental lactogen). Congenital malformations in a diabetic mother occur within first 8 weeks of gestation when most women are just begining prenatal care. Therefore preconceptional counselling is very essential in a diabetic mother Screening for diabetes during pregnancy : Glucose Challenges Test ? Screening for gestational diabetes is performed by orally administering 50g of glucose and measuring venous plasma glucose 1 hour later. (The test is done irrespective of the time of last meal and can be done at any time of day) Interpretation of result : - Plasma glucose : Interpretation - 140 mg/dl Fuher testing by GTT required - 140mg/dI Fuher testing not required. - >200mg/dI No fuher testing required as values > 200mg/dl confirm the diagnosis of gestational diabetes. Time for screening : between 24 and 28 weeks of gestation (patients at high risk should be screened as early as possible and if initial screenings is negative it can be repeated between 26 and 30 weeks). Instead of 'universal screening', a 'selective screening' should be adopted Glucose Tolerance test : Patients with abnormal screening test are followed by a 3 hour glucose tolerance test (GTT) The test is performed with 100gm of glucose.(As recommended by ACOG. Note: WHO recommends 75 gm GTT) Upper limit of normal for the 3 hour glucose tolerance test during pregnancy Fasting : 95mg/dI - One hour 180mg/dI - Two hour 155mg/dI - Three hour : 140mg/dI Result If two or more of these values are abnormal : Gestational diabetes is confirmed. if one value is abnormal : Increased risk of complications like macrosomia and preeclampsia - eclampsia. (Though gestational diabets is not present) The GTT should be performed in the morning after an overnight fast of atleast 8 hours but not more than 14 hours and after atleast 3 days of unrestricted diet ( 150 gm carbohydrated) and physical activity The subject should remain seated and should not smoke during the test