Clinical Research Directory

Cervical Length Reference Range at 28-34 Weeks in Singleton Pregnancies

Cervical length, measured via transvaginal ultrasound, changes as pregnancy progresses. However, reference information for interpreting cervical length measurements during late pregnancy in Vietnam remains limited. This study aims to describe gestational-age-specific cervical length percentiles in a selected population of women with singleton pregnancies receiving care at My Duc Hospital. The study plans to enroll 294 women who have a documented cervical length greater than 25 mm between 16 weeks 0 days and 24 weeks 0 days of gestation. Participants will be recruited between 28 weeks 0 days and 33 weeks 6 days of gestation. Each participant may undergo up to three cervical length assessments during scheduled antenatal visits, occurring approximately two weeks apart: from 28 weeks 0 days to 29 weeks 6 days, from 30 weeks 0 days to 31 weeks 6 days, and from 32 weeks 0 days to 33 weeks 6 days. No separate research-only visit is planned. At each assessment, the sonographer will obtain at least three technically acceptable measurements and will record the shortest measurement. These measurements will be used to estimate cervical length percentiles by gestational age. Participants will also be followed through delivery, and pregnancy and newborn outcomes will be obtained from medical records. This study is observational and will not assign treatments or alter routine clinical care.