 After preterm labor has been confirmed and informed consent has been obtained, patients will be randomized by the use of sequentially numbered, sealed opaque envelopes to receive intravenous magnesium 6gm load plus 6gmper hour IV to abolish contractions versus a calcium channel antagonist nifedipine 30mg loading, then 10 - 20mg q 4 - 6 hours versus antiprostaglandin indomethacin 100mg rectal suppositories may repeat x1 and then 25 - 50mg q 6 hours over 48 hours. The amount of each tocolytic over time will be recorded. If this fails to abolish uterine activity and there is no contraindication to continuing pregnancy eg abruptio placenta, chorioamnionitis, non-reassuring fetal tracing, etc. subcutaneous terbutaline beta-agonist will be given subcutaneously 250mg as an adjunctive measure to abolish contractions. As is our routine we will use blood tests, amniotic fluid assessment and ultrasound to detect infection or abruptio placenta which would lead to delivery after cessation of tocolytic treatment. 