Can transabdominal ultrasound identify women at high risk for short cervical length?

OBJECTIVE

To determine whether transabdominal cervical length screening could identify women at high risk for having a short cervix on transvaginal ultrasound.

DESIGN

Retrospective cohort study.

SETTING

Tertiary referral center.

POPULATION: A total of 703 patients with a singleton pregnancy at 18 to 23(+6) weeks of gestation who underwent transabdominal and transvaginal cervical length assessment during anatomy ultrasound at a single institution between January 2007 and October 2011.

METHODS

Electronic medical records were reviewed to identify women who met the study criteria.

MAIN OUTCOME MEASURES: The primary outcome was the number of women with a short transabdominal cervical length (defined as ≤ 30 mm) who needed to undergo transvaginal ultrasound to detect one woman with a short transvaginal cervical length of ≤ 20 mm.

RESULTS

In all, 703 patients were included in the primary analysis; 3.42 women with transabdominal cervical length ≤ 30 mm needed to undergo transvaginal ultrasound to detect one woman with transvaginal ultrasound cervical length ≤ 20 mm. Of women with short transvaginal cervical length ≤ 20 mm, 89.8% had a transabdominal measurement ≤ 30 mm and 96.7% had a transabdominal measurement ≤ 33 mm.

CONCLUSIONS

Screening of transabdominal cervical length may represent a useful strategy for detecting women with short cervix on transvaginal ultrasound.