Cervical cerclage, an encircling suture placed around the cervix before or during pregnancy, has been used to help structural defects or cervical weakening in high-risk women with a shortened cervix. Studies have shown that cerclage is associated with a decrease in preterm labor and in perinatal death when used in women with a prior preterm labor and a cervical length of 25 mm or less. Cervical cerclage is performed as an attempt to prolong pregnancy in certain women who are at higher risk of preterm labor. The McDonald and Shirodkar techniques, or modifications thereof, are the most commonly used methods for placing a cerclage. The most recent Cochrane review on progesterone for the prevention of Preterm labor examined evidence on the use of any progestogen for women at risk of Preterm labor either because of a previous Preterm labor or because of a short cervix. Although the two risk categories were examined separately, all progestogens were considered together. For women with a previous Preterm labor, the review suggested that progestogens reduce the risk of Preterm labor before 34 gestational weeks, reduce perinatal mortality, reduce the incidence of low birthweight and reduce neonatal death.