Is Uterocervical Angle Associated with Gestational Latency after Physical Exam Indicated Cerclage?

Beyond Cervical Length: Association between Postcerclage Transvaginal Ultrasound Parameters and Preterm Birth

OBJECTIVE

To assess the value of transvaginal ultrasound parameters after cerclage placement in estimating the risk of spontaneous preterm birth.

STUDY DESIGN

This is a retrospective cohort at a single tertiary care center from 2013 to 2016. Women carrying a singleton, nonanomalous fetus with cerclage in situ and at least one postcerclage transvaginal ultrasound from 16^0/7 to 25^6/7 weeks' gestation were included. In addition to abstracting maternal demographic and obstetric characteristics, two study investigators separately reviewed each of the images from the first transvaginal ultrasound after cerclage placement, masked to pregnancy outcomes. We measured the angle between the anterior uterine wall and cervical canal at the internal os and external os, closed canal length above and below the stitch, width of the anterior and posterior cervix at the level of the cerclage, and stitch distance from the cervical canal. The presence of additional ultrasound findings such as sludge and cervical funneling was also noted. The main outcomes were preterm birth < 34 weeks and preterm birth < 37 weeks. Transvaginal ultrasound parameters were compared between women with preterm birth and those without preterm birth using chi-square, Fisher's exact, and Wilcoxon's rank-sum tests, as appropriate. Log binomial regression was used to estimate the relative risk of preterm birth for all significant obstetric and ultrasound characteristics.

RESULTS

A total of 102 women met inclusion criteria: 58% had history-indicated, 20% ultrasound-indicated, and 23% exam-indicated cerclages. Of these, 28 (27.5%) women delivered at < 34 weeks' gestation, and 48 (47.0%) women delivered at < 37 weeks' gestation. Preterm birth did not vary by race, maternal age, insurance, smoking, or gestational age of the earliest prior preterm birth (for multiparous women), but women who had preterm birth were more likely to have exam-indicated cerclage. There were several transvaginal ultrasound parameters associated with preterm birth < 34 weeks and preterm birth < 37 weeks. Of these, cervical length below the stitch, stitch distance from the cervical canal, straight cervical canal, funneling to or past the stitch, and presence of sludge had the greatest effect sizes.

CONCLUSION

Rates of preterm birth are high postcerclage. In addition to measuring cervical length, utilization of postcerclage transvaginal ultrasound to evaluate the location of the cerclage within the cervix, the curvature of the cervical canal, and the presence of funneling and sludge may help identify women who are at the highest risk for preterm birth.

Assessment of Uterocervical Angle Width as a Predictive Factor of Preterm Birth: A Systematic Review of the Literature

Background

Uterocervical angle (UCA) has been recently proposed as a potential marker that could accurately predict preterm birth (PTB). The purpose of the present systematic review is to accumulate current evidence and provide directions for future research.

Materials and Methods

We used the Medline (1966–2018), Scopus (2004–2018), Clinicaltrials.gov (2008–2018), EMBASE (1980-2018), Cochrane Central Register of Controlled Trials CENTRAL (1999-2018), and Google Scholar (2004-2018) databases in our search.

Results

Eleven studies were finally included in the present systematic review that evaluated data from 3,018 women. The significant heterogeneity in terms of outcome reporting and outcome reporting measures (use of optimal cut-off values) precluded meta-analysis. However, existing data support that second trimester UCA measurement might be used as a predictive factor of PTB <34 weeks, as at least two studies in unselected singleton pregnancies and two studies in pregnancies with an ultrasonographically shortened cervix seem to support this hypothesis. The most commonly reported cut-off values were 105° and 95°.

Conclusions

UCA measurement during the second trimester of pregnancy may be a useful method of determining women at risk of delivering preterm. However, more studies are needed to assess the reproducibility of these findings and reach conclusive evidence.

Uterocervical angle: an ultrasound screening tool to predict satisfactory response to labor induction

Background: A wide uterocervical angle >95° detected during the second trimester was associated with an increased risk for spontaneous preterm birth.Objective: We aimed to determine whether an ultrasonographic marker, uterocervical angle, correlates with satisfactory response to labor induction.Study design: We conducted a prospective cohort study from May 2016 through December 2017 of singleton term gestations undergoing transvaginal ultrasound for cervical length screening and uterocervical angle measurement. Uterocervical angle was measured between the lower uterine segment and the cervical canal. Latent phase duration >720 min was accepted to be a prolonged latent phase. The primary outcome was a prediction of satisfactory response to labor induction (latent phase duration <720 min).Results: Both anterior uterocervical angle (AUC = 0.802, p < .001) and the cervical length (AUC = 0.679, p < .05) significantly predicted satisfactory response to labor induction. Optimal cutoff value was obtained at the value of 97° (64% sensitivity, 91% specificity) for anterior uterocervical angle and 27 mm (64% sensitivity, 64% specificity) for the cervical length. Kaplan-Meier survival analysis showed that duration from labor induction to delivery was significantly higher in a group with longer cervical length (p = .04), additionally labor induction to delivery time was significantly higher in a group with lower UCA (p = .04).Conclusions: Both the cervical length and anterior uterocervical length were predictors for the satisfactory response to labor induction, and both parameters were found to be significantly associated with time from induction to delivery in survival analysis.