I found out at 17 weeks that i had a huge aneurysm in my heart and if I stayed pregnant, the baby would be premature. We kept the baby and so at 24 weeks they gave me the betamethasone in case I had to have the baby before 28 weeks. At 27 weeks I went into the hospital for monitoring so at 28 weeks I got a booster of the shots. at 28 weeks 2 days they discovered that my aorta had a tear in it, so I had an emergency csection (and heart surgery at the same time). My son is now 13 days old and was only briefly on a ventilator (until they realized he was out performing it). So he's been breathing on his own since birth. I'd say go for the shots.
A study of 46 women who delivered an infant before 34 weeks of gestation found that a course of another corticosteroid (betamethasone, 2 intramuscular injections of mg of betamethasone 24 hours apart) given between 3 and 9 days before delivery resulted in delayed lactogenesis II and lower average milk volumes during the 10 days after delivery. Milk volume was not affected if the infant was delivered less than 3 days or more than 10 days after the mother received the corticosteroid. An equivalent dosage regimen of cortisone might have the same effect.