The current study aimed to evaluate the efficacy of progesterone supplementations to prevent preterm birth in women with a high risk of preterm birth. Patients and method: An analytic preventive interventional trial study was conducted in Salahadeen General Hospital, Iraq during the period from the 1st of January to the 30th of June 2023. A convenient sample of 100 pregnant women at 20-28 weeks of gestation with a high risk of preterm birth was enrolled. Those women were submitted into two groups: The intervention group: Included 50 pregnant women who receive progesterone supplementations. Control group: Included 50 pregnant women who received a placebo. The pregnant women were followed until delivery, the outcome including preterm birth <34 weeks, preterm birth <37 weeks, and neonatal outcome including birthweight, birth asphyxia, and neonatal intensive care unit admission. Results: The incidence of preterm birth was significantly lower in the intervention than in the control group (P-value=0.044). Among those with a cervical length of <25mm the incidence of preterm birth (<34 weeks and <37 weeks) was significantly lower in the intervention group compared to the control group (P-value=0.497). The percentage of neonates with a birth weight of <2.5 kg was significantly lower in the intervention group compared to the control group (P-value=0.017). Conclusion: Progesterone supplementation was significantly effective in reducing the incidence of preterm birth among pregnant women who were at risk of preterm birth. Progesterone supplementation was significantly effective in reducing the incidence of preterm birth among pregnant women with a short cervix. Progesterone supplementation was significantly effective in reducing the percentage of neonates with of birth weight of <2.5kg.

Keywords: Preterm birth, Progesterone, Cervical length, Iraq