Is dynamic cervical shortening during symptomatic contractions predictive of preterm delivery in patients with a normal baseline cervical length?

OBJECTIVE: The purpose of this study was to determine whether dynamic cervical change in symptomatic patients with a normal baseline cervical length (CL; >or=30 mm) is predictive of preterm delivery (PTD). METHODS: A prospective observational study was performed in 120 symptomatic patients between 23 and 34 weeks' gestation. Patients underwent standardized CL sonography with contraction monitoring, and CL measurements were recorded each minute for approximately 10 minutes. Initial and minimum CLs as well as the presence of dynamic change were assessed for prediction of PTD. RESULTS: Forty-seven patients (39.2%) had dynamic cervical change and delivered at a mean gestational age +/- SD of 37.1 +/- 2.7 weeks compared to 38.7 +/- 1.5 weeks for those without dynamic change (P < .01). A larger proportion of those with dynamic change delivered before 37 weeks (43% versus 15%; P < .01) and before 35 weeks (19% versus 0%; P < .01). Multivariable logistic regression analysis showed that dynamic cervical change was predictive of PTD, but not independently of the minimum CL. Statistical analyses were completed using the Student t test, chi(2) test, Fisher exact test, Wilcoxon rank sum test. and logistic regression as appropriate. CONCLUSIONS: Although symptomatic patients with a normal baseline CL who have dynamic shortening generally deliver at term, they appear to be at increased risk of PTD.

Is transabdominal sonography of the cervix after voiding a reliable method of cervical length assessment?

OBJECTIVE: The purpose of this study was to assess the correlation and agreement between transvagi-nal and transabdominal cervical length measurement after bladder emptying as well as the feasibility of transabdominal sonography in cervical length screening. METHODS: This was a prospective cohort study involving 287 participants (14-34 weeks' gestation) from January to December 2003. After voiding, transabdominal and transvaginal cervical length measurements were obtained. The optimal trans-abdominal technique was established during an unblinded series of transabdominal and transvaginal cervical length measurements (n = 96). The same measurements were obtained in 191 participants under a blinded 2-sonographer protocol. The transabdominal cervical length cutoff to ensure 100% sensitivity in detecting a short cervix (

Loss of progesterone receptor-mediated actions induce preterm cellular and structural remodeling of the cervix and premature birth.

A decline in serum progesterone or antagonism of progesterone receptor function results in preterm labor and birth. Whether characteristics of premature remodeling of the cervix after antiprogestins or ovariectomy are similar to that at term was the focus of the present study. Groups of pregnant rats were treated with vehicle, a progesterone receptor antagonist (onapristone or mifepristone), or ovariectomized on day 17 postbreeding. As expected, controls given vehicle delivered at term while rats delivered preterm after progesterone receptor antagonist treatment or ovariectomy. Similar to the cervix before term, the preterm cervix of progesterone receptor antagonist-treated rats was characterized by reduced cell nuclei density, decreased collagen content and structure, as well as a greater presence of macrophages per unit area. Thus, loss of nuclear progesterone receptor-mediated actions promoted structural remodeling of the cervix, increased census of resident macrophages, and preterm birth much like that found in the cervix at term. In contrast to the progesterone receptor antagonist-induced advance in characteristics associated with remodeling, ovariectomy-induced loss of systemic progesterone did not affect hypertrophy, extracellular collagen, or macrophage numbers in the cervix. Thus, the structure and macrophage census in the cervix appear sufficient for premature ripening and birth to occur well before term. With progesterone receptors predominantly localized on cells other than macrophages, the findings suggest that interactions between cells may facilitate the loss of progesterone receptor-mediated actions as part of a final common mechanism that remodels the cervix in certain etiologies of preterm and with parturition at term.