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Objective  The aim of this study was to estimate if preterm premature rupture of membranes in women with cerclage is due to the cerclage itself or rather the underlying risk factors for preterm birth in this population. Study Design  This was a retrospective cohort study of singleton pregnancies who underwent Shirodkar cerclage by a single maternal–fetal medicine practice between 2005 and 2019. The control group was an equal number of randomly selected women with a singleton gestation who had a prior preterm birth and were treated with 17-OH-progesterone but no cerclage. Patients with major uterine anomalies or fetal anomalies were excluded. The primary outcome was preterm premature rupture of membranes prior to 34 weeks. Chi-square and logistic regression were used. Results  A total of 350 women with cerclage (154 [44%] history-indicated, 137 [39%] ultrasound-indicated, and 59 [17%] exam-indicated) and 350 controls were included. Preterm premature rupture of membranes prior to 34 weeks did not differ between the groups (8.9% in cerclage vs. 6.0% in controls, p  = 0.149, adjusted odds ratio 0.62, 95% confidence interval: 0.24–1.64) nor between the different cerclage indications (9.1% of history-indicated, 7.3% of ultrasound-indicated, and 11.9% of exam-indicated, p  = 0.582). This study had 80% power with an α error of 0.05 to detect an increase in preterm premature rupture of membranes prior to 34 weeks from 6.0% in the control group to 12.0% in the cerclage group. Conclusion  Cerclage does not increase the risk of preterm premature rupture of membranes prior to 34 weeks compared with other women at increased risk of preterm birth. The observed association between cerclage and preterm premature rupture of membranes is likely due to underlying risk factors and not the cerclage itself. The risk of preterm premature rupture of membranes prior to 34 weeks in women with cerclage is 10% or less and does not appear to differ based on cerclage indication. Key Points Cerclage does not increase the risk of PPROM. Risk of PPROM with cerclage is approximately 10%. Risk does not appear to vary by indication. [ABSTRACT FROM AUTHOR]

Objective  This article assesses the effect of weekly intramuscular 17α-hydroxyprogesterone caproate (17P) on midtrimester cervical length (CL) in patients with prior spontaneous preterm birth. Study Design  Retrospective cohort study of all singletons that underwent CL screening at a single institution from 2011 to 2016. The timing of 17P exposure was assessed. The primary outcome was shortest midtrimester CL. Secondary outcomes included gestational age at delivery, rate of short cervix, cerclage, preterm labor admission, and preterm premature rupture of the membranes (PROM). Multivariable regression analysis was used to model the relationship between 17P exposure and shortest CL, controlling for selected covariates. Results  Of 409 women who underwent screening, 211 received and 198 did not receive 17P prior to the last CL. Rates of short cervix and cerclage were similar between groups. After adjusting for covariates, the shortest CL was significantly shorter in the 17P group. In a secondary analysis, those who received any 17P (n  = 293) versus those who did not (n  = 116) had higher rates of preterm PROM, preterm labor admission, and cerclage. After controlling for covariates, gestational age at delivery was significantly lower in those receiving 17P. Conclusion  In high-risk patients undergoing CL screening for ultrasound-indicated cerclage, 17P did not prevent midtrimester cervical shortening or prolong gestation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective  To determine the risk of spontaneous preterm delivery (SPTD) associated with transvaginal cervical length (TVCL) in an unselected cohort. Study Design  This is a retrospective study of serial TVCLs in unselected twin gestations. Receiver operator curves for SPTD were constructed from TVCLs at 18, 20, 22, and 24 weeks. Prediction thresholds were determined using a false discovery rate of 10%. The risk of SPTD was compared with previously published, prospective data from a meta-analysis. Results  A total of 1,228 women were included. SPTD occurred prior to 35 weeks in 232 (18.9%), 126 (10.3%), and 24 (2.0%) women prior to 35, 32, and 28 weeks. TVCL was most predictive at 22 weeks (area under the curve = 0.67). TVCL thresholds for predicting SPTD prior to 35, 32, and 28 weeks were 3.1, 3.0, and 2.9 cm. Compared with a previous meta-analysis, the risk of SPTD < 34, 32, and 28 weeks was lower (positive likelihood ratio 9.0 vs. 5.4, 10.1 vs. 5.9, and 9.6 vs. 4.3). Conclusion  TVCL is modestly predictive of SPTD in twin gestations. Compared with previous prospective studies, this cohort has lower risk of SPTD at similar TVCLs. [ABSTRACT FROM AUTHOR]