The use of the Cervilenz device to aid in the diagnosis of premature labor

A short cervix measured by transvaginal ultrasound has been correlated with increased risk for preterm delivery (PTD). Many patients presenting with a complaint of possible premature labor (PL); may not have access to cervical length (CL) screening by ultrasound. Cervilenz is an FDA cleared disposable device for obtaining vaginal CL measurements. This study was conducted to correlate Cervilenz measurements of CL with the occurrence of PTD.

Women presenting with regular uterine contractions at gestational age (GA) ≥22 and <34 weeks with intact membranes and cervical dilation <3 cm were recruited. A speculum examination was performed and Cervilenz measurement of CL was obtained. Patients were treated with tocolytics and/or corticosteroids based upon the attending physician's judgment. The occurrences of PTD as a result of PL or premature rupture of membranes within 7 days, <32 weeks, <34 weeks and <37 weeks, were determined. Patients who were delivered preterm for other maternal or fetal indications were excluded. Negative predictive value (NPV) was calculated.

Of the 220 women recruited, 20 were subsequently excluded from analysis because they required PTD for unrelated indications. The mean GA at enrollment was 29.8 ± 2.8 (SD) weeks. One (0.5%), 2 (1.0%), 4 (2.0%) and 29 (14.5%) women delivered at ≤7 days from enrollment, ≤32 weeks, ≤34 weeks, and ≤37 weeks, inclusively. Seventy-seven (38.5%), 39 (19.5%) and 19 (9.5%) women had Cervilenz measurement of ≤30, ≤25 and ≤20 mm, respectively. The NPV for a Cervilenz measurement of >20 mm for delivery at, ≤32, ≤34 and ≤37 weeks were 99.2%, 98.3% and 86.7%, respectively.

Cervilenz measurement >20 mm appears to have high NPV for PTD prior to 34 weeks.