Intervention:~The study subjects will be randomized to receive twice daily tablets of either 100 mg of OMP (Uterocare®, October Pharma , Sixth of October city, Egypt) or placebo from enrollment (14-18 weeks) until 36 weeks or delivery, whichever occurs first. The patients and medical staff will be blinded to the study medication allocation.~Method of Randomization:~All patients who are fit for admission into the study will pull one of the numbered sealed identical black bags containing either the active medicine (=25%), the placebo (with the aim of admission into data collection, =25%), or a placebo together with a short note explaining that they will not be admitted to the study (=50%) and that they can give back their bag to the head nurse.~The code for the 424 (106x4) bag numbers is a confidential computer generated random number list (generated using MedCalc© Software bvba, Ostend, Belgium). It will be left, in a sealed envelope, with the head nurse of the antenatal clinic, till the end of data collection.ruptured membranes.~5. Obstetric ultrasound for gestational age, amniotic fluid volume, fetal weight, placental position, fetal anomalies.~6. Transvaginal ultrasound is not always available for cervical length assessment in ASUMH, so it will not be a necessary step in patients assessment but will be done whenever available.~Follow up:~Patients will be followed up regularly, at twice monthly intervals, in the antenatal clinic of Ain Shams University Maternity Hospital until delivery. They will be instructed to return to the hospital when recurrence of symptoms of preterm labor, rupture of membranes, or vaginal bleeding. There will be telephone call follow ups routinely to ensure adherence to the study protocol.
This is a randomized, double-blind, placebo-controlled study.