ObjectiveTo assess the impact of progesterone treatment on maternal and neonatal outcomes in women with a history of preterm birth and short cervical length diagnosed after 24 weeks of gestation.MethodsA retrospective cohort study included women with a history of preterm birth and a transvaginal sonographic cervical length measurement of ≤ 25 mm, diagnosed between 24+0 and 33+6 weeks of gestation. Exclusion criteria included prior progesterone treatment, cervical cerclage, or pessary. The study population was divided into the progesterone treatment group and the non-treatment group.ResultsThe study included 104 women, with 46.2% (48/104) receiving progesterone treatment and 53.8% (56/104) not receiving treatment. The rate of spontaneous preterm birth before 37 weeks of gestation was 43% (24/56) in the non-treatment group and 31% (15/48) in the progesterone treatment group (P = 0.14); the rate of spontaneous preterm birth before 34 weeks was 7% (4/56) in the non-treatment group and 0% (0/48) in the progesterone treatment group (P = 0.05). Progesterone treatment was associated with a significant decrease in neonatal intensive care unit admissions (OR 0.20, 95% CI 0.05–0.74) and in the neonatal hospitalization period (mean difference in days 2.43, 95% CI 0.44–4.42). The risk of recurrent spontaneous preterm birth was highest (71%) among women with two or more previous preterm deliveries who did not receive progesterone treatment, and lowest (24%) among women with one previous preterm delivery who received progesterone treatment.ConclusionProgesterone treatment was associated with a reduction in rates of spontaneous preterm birth before 34 weeks of gestation, neonatal intensive care unit admission, and neonatal length of stay in high-risk patients, even when initiated after 24 weeks of gestation.

Objective: To determine whether vaginal progesterone treatment for women with a short cervix, diagnosed after 24 weeks of pregnancy, reduces preterm birth rates. Methods:A retrospective cohort study that included women with a singleton pregnancy, threatened preterm labor, and a short cervix measured between 24 +0 and 33 +6 weeks. Women who received vaginal progesterone were compared with women who did not receive progesterone. The primary outcome was spontaneous preterm birth before 37 weeks of pregnancy.Results: Patients who received vaginal progesterone had a lower rate of preterm delivery at less than 37 weeks of pregnancy (18.2% [22/121] versus 28.9% [73/253]; adjusted hazard ratio 0.50; 95% confidence interval 0.28-0.73, P = 0.001). The diagnosis-to-delivery interval was significantly greater in patients who received progesterone than in those who did not-median time to delivery in weeks: 8.2 (interquartile range [IQR] 6.2-9.8) versus 6.6 (4.8-8.8), (P < 0.001). The frequency of neonatal intensive care unit admission was significantly lower in patients who received progesterone than in those who did not (8.3% [10/121] versus 16.2% [41/253], P = 0.04). Conclusions:The administration of vaginal progesterone to patients with an episode of threatened premature labor and a short cervix presenting after 24 weeks of pregnancy was associated with lower rates of premature births.