D.H.
Hi D. ~
There's no way to know how soon someone will go into labor after starting their meds. Everyone's different. I've seen women have all kinds of pre-term labor and then come off their meds and not go into labor until they're due. And other women go into labor while still on the meds.
good luck...and congratulations on making it this far! A little bit more and the lungs should be fine!
D.