Makena
"This is an awesome medicine. I am so happy to have been able to use in pregnancy.  I was on it from 20 weeks to 36..they say 12 days after you stop the shot you go into labor, that was true for me as well. This is the only medication that helped me complete a pregnancy.  It's awesome! Yes the shot in the butt hurts and you stay sore about 4 days. But it was totally worth it."