Abstract
BACKGROUND: To determine whether the combination of vaginal progesterone and cervical pessary initiated during the second trimester reduces the incidence of preterm birth and enhance neonatal outcomes among women diagnosed with singleton pregnancies and a short cervix. STUDY DESIGN: We conducted a retrospective cohort study involving 322 pregnant individuals with singleton gestations and a sonographically confirmed short cervix (≤ 25 mm), managed at Akbarabadi Hospital, a tertiary referral center. Participants were allocated into two treatment groups: one received both vaginal progesterone (200 mg daily) and an Arabin cervical pessary, and the other received progesterone alone. Primary outcomes included the incidence of spontaneous preterm birth before 34 and 37 weeks of gestation. Secondary outcomes encompassed neonatal morbidity, NICU admission, birth weight, and maternal complications. Comparative analyses were conducted using Cox proportional hazards regression and standard statistical tests, with adjustments for potential confounders. RESULTS: Preterm birth before 34 weeks was significantly lower in the combination group (3.1%) compared to the progesterone-only group (12.4%; p = 0.002). Similarly, births before 37 weeks were reduced (22.4% vs. 37.3%; p = 0.003). The combination group showed better neonatal outcomes, including fewer NICU admissions (34.8% vs. 54.0%; p = 0.012), shorter NICU stays were more frequent in the combination group (66% discharged within 3 days vs. 34% in progesterone-only group; p = 0.012), and a lower need for resuscitation (5.6% vs. 12.4%; p = 0.032). Maternal complications (including postpartum hemorrhage, infection, and ICU admissions) were noticeably lower in the combination group (2.5% vs. 10.6%; p = 0.003). CONCLUSION: Combining vaginal progesterone with a cervical pessary during mid-pregnancy can significantly reduce the risk of preterm birth and improve outcomes for both mother and baby in singleton pregnancies with a short cervix. These findings support incorporating dual therapy into clinical practice guidelines as an effective approach to preventing preterm birth in high-risk populations. These findings suggest that dual therapy may reduce preterm birth risk, but confirmation in prospective randomized trials is warranted.