137: Ultrasonographic evaluation of cervical length (CL) and myometrial thickness (MT) as predictors of latency interval in PPROM

Abstract

THICKNESS (MT) AS PREDICTORS OF LATENCY INTERVAL IN PPROM CHRISTIAN M. PETTKER, HUMBERTO AZPURUA, MERT O. BAHTIYAR, ANNA SFAKIANAKI, STEPHEN F. THUNG, IRINA A. BUHIMSCHI, CATALIN S. BUHIMSCHI, Yale University, Ob./ Gyn.&Reprod Sci., New Haven, Connecticut OBJECTIVE: Cervical shortening and myometrial thickness have been independently shown to correlate with latency interval in women with PPROM. This study was conducted to determine whether the combination of CL and MT or addition of other ultrasound parameters strengthens the association of CL with latency. STUDY DESIGN: We prospectively measured CL and lower uterine segment (LUS) MT in 40 women with PPROM (GA 30.4 2.9wks). On admission, transvaginal ultrasound was used to determine cervical length and thickness (anterior and posterior lip). Transabdominal ultrasound was used to measure LUS MT, AFI, and EFW. Latency was defined as the time from sonographic measurements to delivery. All patients were managed based on institutional protocols which included antibiotics and steroids. Parametric, nonparametric, linear regression and ROC analyses were employed as appropriate. RESULTS: 1) The median latency interval overall was 2 [0-35] days, and 43% (17/40) of women went into spontaneous labor. 2) Women with CL 2.5cm (n 19) had a significantly shorter median latency interval (CL 2.5: 1 [1-5] vs CL 2.5: 7 [0-35] days, p 0.001). 3) A CL 2.5cm had 89% sensitivity, 76% specificity, LR 3.8, and –LR 0.1 in predicting delivery within 48 hours. 4) Addition of neither LUS MT nor the other sonographic parameters improved test performance in ROC analysis. CONCLUSION: We provide evidence that in women with PPROM, CL evaluation is a useful clinical test to aid the managing team in predicting the latency interval. A cervical length 2.5cm is highly suggestive of delivery in 48 hours. This information is important for patient counseling and mobilization of resources. Addition of LUS MT measurements or other ultrasound parameters does not aid in the predictive value of CL measurements.