Cerclage On LOw Risk Singletons: Cervical Cerclage for Prevention of Spontaneous Preterm Birth in Low Risk Singleton Pregnancies With Short Cervix

Singleton pregnancies between 18 0/7 to 23 6/7 weeks without a prior spontaneous preterm birth found to have a short transvaginal ultrasound cervical length (\<=25mm) and meeting all other eligibility criteria will be randomized to either cervical cerclage or control (no cerclage). Aside from cerclage placement, management of included women will be the same including recommendation for daily vaginal progesterone 200mg suppository or 90mg gel from randomization until 36 6/7 weeks. The primary outcome will be the incidence of spontaneous preterm birth \<35 weeks