Prevention of preterm labor will reduce perinatal mortality. Screening of cervical length by ultrasound should begin at 16 weeks by transvaginal ultrasound. If the cervical length is more than 35 mm, the exam should be repeated every 2 to 3 weeks till 32 weeks. If the cervical length is between 25 and 35 mm the ultrasound screening should be done weekly or biweekly. Fetal fibronectin estimation should provide supplemental information. If the cervical length is less than 25 mm cervical cerclage should be performed if gestational age is less than 22 weeks. Progesterone therapy is preferred if the gestational age is more than 22 completed weeks.
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