Second-trimester cervical sonography: features other than cervical length to predict spontaneous preterm birth.
OBJECTIVE
To estimate whether cervical and lower uterine segment characteristics other than cervical length and funneling predict recurrent preterm birth.


METHODS
We conducted a secondary analysis of a multicenter, blinded observational study of 181 women with singletons and prior spontaneous preterm births. Endovaginal ultrasonic examinations were performed at 2-week intervals between 16 0/7 weeks and 23 6/7 weeks of gestation. Cervical canal contour (straight/curved), cervical position (horizontal/vertical), posterior cervical width, lower uterine segment thickness, vascularity, endocervical canal dilation, with or without associated membrane prolapse and chorioamnion visible at the internal os, were systematically assessed.


RESULTS
At the initial sonogram (16 0/7-18 6/7 weeks), membranes visible overlying the internal os (relative risk 1.9, confidence interval [CI] 1.2, 3.1) and canal dilation of 2-4 mm (relative risk 2.6, CI 1.4, 4.7) were significant predictors of spontaneous preterm birth of less than 35 weeks in univariate analyses. Only canal dilation remained statistically significant after controlling for cervical length (odds ratio 5.5, CI 1.1, 28.6).


CONCLUSIONS
Endocervical canal dilation of 2-4 mm during second-trimester endovaginal sonography was associated with an increased risk of recurrent preterm delivery independent of cervical length.


METHODS
II-2
Yost
Nicole P
NP
Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9032, USA. Nicole.Yost@utsouthwestern.edu
Owen
John
J
Berghella
Vincenzo
V
MacPherson
Cora
C
Swain
Melissa
M
Dildy
Gary A
GA
Miodovnik
Menachem
M
Langer
Oded
O
Sibai
Baha
B
D000328:Adult; D002584:Cervix Uteri / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007747:Labor Stage, First; D007752:Obstetric Labor, Premature / Q000209:etiology*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D016216:Ultrasonography, Prenatal