Which amongst the following statements is true?

Unlike other oral hypoglycemic agents, glyburide and metformin both are being increasingly used for GDM (not for ove DM) and are found to be safe. Patients with GDM/DM should be delivered between 38 and 39 weeks of gestation, as there is a risk of sudden IUFD at full term. Hormones which do not cross the placenta are 1. Insulin, 2. PTH, and 3. Calcitonin. Lung maturity is delayed in DM/GDM. - L/S >2:1 is not reliable. - Phosphatidyl glycerol in amniotic fluid is 100% confirmatory of lung maturity in these cases.