A 28-year-old woman at 24 weeks presents with cervical length of 16 mm on transvaginal ultrasound and no symptoms. She has no prior history of preterm birth (nulliparous). The most evidence-based intervention to reduce her risk of spontaneous preterm birth is:

• A Cervical cerclage (McDonald stitch)
• B Arabin pessary
• C 17-alpha-hydroxyprogesterone caproate (17-OHPC) IM weekly
• D Vaginal progesterone (200 mg micronised progesterone nightly) ✓

Explanation

For asymptomatic singleton pregnancies with short cervical length (<25 mm) detected on mid-trimester transvaginal ultrasound, without prior preterm birth history, vaginal progesterone (200 mg micronised progesterone or 90 mg progesterone gel nightly) is the evidence-based intervention (Fonseca et al. NEJM 2007, Hassan AJOG 2011) reducing PTB <34 weeks by ~45%. Cervical cerclage is indicated for women with prior PTB AND short cervix (history-indicated or ultrasound-indicated), not for nulliparous women with short cervix alone. The Arabin pessary failed to show benefit in the OPPTIMUM and ProTWIN trials.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.