Cerclage for Preterm Birth Prevention in Twin Gestation with Short Cervix: a Retrospective Cohort Study
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Ultrasound Obstet Gynecol 2016; 48: 752–756 Published online 1 November 2016 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/uog.15918 Cervical cerclage for preterm birth prevention in twin gestation with short cervix: a retrospective cohort study C. HOULIHAN*, L. C. Y. POON†, M. CIARLO*, E. KIM*, E. R. GUZMAN* and K. H. NICOLAIDES† *Department of Obstetrics and Gynecology, Saint Peter’s University Hospital (SPUH), New Brunswick, NJ, USA; †Harris Birthright Research Centre for Fetal Medicine, King’s College Hospital, London, UK KEYWORDS: cerclage; cervical ultrasound; cervix; prematurity; twins ABSTRACT INTRODUCTION Objective To determine if cervical cerclage reduces the With a prevalence of less than 2% of all pregnancies, rate of spontaneous early preterm birth in cases of twin pregnancies account for more than 25% of dichorionic–diamniotic (DCDA) twin gestation with an spontaneous early preterm births1,2.Strategiesfor ultrasound-detected short cervix. prevention of preterm birth include the use of vaginal progesterone, cervical pessary and cervical cerclage. Methods This was a retrospective cohort study of 40 Individual patient data meta-analyses (IPDMAs) from consecutive DCDA twin gestations at Saint Peter’s randomized controlled trials (RCTs) reported that vaginal University Hospital from November 2006 to November progesterone in twin gestation with a sonographic short 2014 in which cervical cerclage was performed for an cervix did not significantly reduce the rate of preterm ultrasound-determined cervical length of 1–24 mm at birth < 33 weeks, but it reduced the risk of composite 16–24 weeks’ gestation. The cases were matched with neonatal morbidity and mortality3,4. The Arabin pessary 40 controls without cerclage for cervical length and has been shown to be effective in reducing early preterm gestational age at cervical assessment. The primary birth in singleton gestations with short cervix and has outcome measure was spontaneous birth < 32 weeks. generated interest in its use in twin gestations5.A Results There was no difference between the two groups RCT in twin gestations found that prophylactic use of in maternal age, body mass index (BMI), cigarette the Arabin pessary reduced the rate of early preterm 6 smoking, use of in-vitro fertilization (IVF), parity and birth, but only in the subgroup with a short cervix . prior spontaneous preterm birth. There were more However, a large multicenter RCT on the use of the Caucasian women among the controls compared with Arabin pessary in unselected twin gestations, administered cases. In the cases, compared with controls, spontaneous either prophylactically or for those with cervical length ≤ delivery < 32 weeks was significantly less frequent (20.0% 25 mm, had no effect on spontaneous birth < 34 weeks 7 vs 50.0%; relative risk, 0.40 (95% CI, 0.20–0.80)). or neonatal outcome . An IPDMA of RCTs primarily In the prediction of spontaneous delivery < 32 weeks, on singletons that included 49 sets of twins found logistic regression analysis demonstrated that the risk was that, in twin gestation with a short cervix, the use of reduced with the insertion of cervical cerclage (odds ratio, cervical cerclage may double the rate of spontaneous early 8 0.22 (95% CI, 0.058–0.835); P = 0.026), corrected for preterm birth . These results led to recommendations maternal age, BMI, racial origin, cigarette smoking, IVF, in the ‘Choosing Wisely’ program (an initiative of the parity and previous preterm birth. American Board of Internal Medicine aimed at advancing a dialogue on avoiding wasteful or unnecessary medical Conclusion In DCDA twin gestation with a short cervix, tests, treatments and procedures) to warn patients against treatment with cervical cerclage may reduce the rate of physicians’ recommendations to perform cerclage for early preterm birth. The findings suggest the need for ashortcervixintwingestation9. The IPDMA was adequate randomized controlled trials on cerclage in twin subsequently repeated, controlling for confounders, and gestations with a short cervix. Copyright © 2016 ISUOG. concluded that cerclage did not reduce the incidence of Published by John Wiley & Sons Ltd. delivery < 34 weeks’ gestation, and its use was associated Correspondence to: Dr E. R. Guzman, Saint Peter’s University Hospital, Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, MOB 4th Floor, 254 Easton Avenue, New Brunswick, NJ 08901, USA (e-mail: [email protected]) Accepted: 9 March 2016 Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. ORIGINAL PAPER Cerclage for twin gestation with short cervix 753 with an increase in respiratory distress syndrome and a white blood cell (WBC) count and differential. The patient birth weight < 1500 g8,10. However, a recent retrospective was observed for a period of up to 48 h before surgery cohort study reported that cerclage in twin gestation with if there was any concern of infection, presence of con- short cervix reduced the rate of early preterm birth (n = 57 tractions and/or labor. An isolated finding of vaginal cerclage vs 83 expectant)11. discharge was evaluated for a definitive diagnosis and Our group has routinely screened twin gestations and treated for at least 2 days. Evaluation of vaginal discharge offered cerclage for a short cervix since the 1990s with included a wet mount microscopic evaluation without encouraging results12. Consequently, we have continued cultures. Amniocentesis was considered if there was a to perform cervical ultrasound screening and offered clinical/laboratory suspicion of infection or the cervix cervical cerclage for a progressively shortening cervix. was dilated with membranes at, or past, the external os. If The purpose of this retrospective cohort study was to amniocentesis was indicated it was the last step of the eval- determine whether cerclage in DCDA twin gestations uation process and performed within several hours of the with short cervix reduces the rate of spontaneous preterm cerclage procedure so that the amniocentesis results were birth < 32 weeks’ gestation. a true assessment of intra-amniotic infection at the time of cerclage placement. Evidence of intra-amniotic infection was defined as WBC count > 50, glucose level < 15 mg/dL PATIENTS AND METHODS and positive Gram staining for WBCs or bacteria. Cul- This was a retrospective cohort study of DCDA twin ges- tures were taken but results were not used in decisions tations with serial vaginal cervical sonography performed regarding cerclage placement. Evidence of intra-amniotic in women who were asymptomatic. Excluded cases were infection was a contraindication for cerclage. During this monoamniotic and monochorionic–diamniotic twin ges- period of observation, repeat vaginal sonography was tations, those with major fetal defects and women who sometimes performed to identify any unfavorable change had placenta previa or complained of contractions or in cervical status. If membranes were beyond the exo- vaginal bleeding, or were found to have signs or symp- cervix, membrane tension, ability to reduce membranes toms of intra-amniotic infection. Approval was obtained digitally and cervical thickness/effacement were assessed from the institutional review boards of the institutions by digital examination to determine technical feasibility of involved. cerclage placement. An effaced cervix was considered evi- The study cases included 49 consecutive asymptomatic dence of labor and a contraindication to cerclage. Those DCDA twin gestations that were routinely screened with that did not satisfy the criteria for cerclage placement dur- vaginal sonographic cervical length assessments every ing the period of preoperative evaluation were not offered 2 weeks from 16 to 24 weeks’ gestation at Saint Peter’s the procedure. Preoperative prophylactic antibiotics, ini- University Hospital, New Brunswick, NJ, USA, between tially clindamycin and then ceftriaxone, and perioperative November 2006 and November 2014. Nine of these cases indomethacin were administered. with cervical length of 0 mm, a dilated external cervical The modified McDonald cervical cerclage procedure os and visible membranes were excluded from subsequent was performed by one of two operators (C.H. and case–control matching and statistical analysis. The 40 E.R.G.). In the operating room, a sponge stick was placed cases included in the analysis were treated with cervical in the endocervical canal to determine the location of cerclage for short cervix at 16–24 weeks’ gestation. the membranes and the anterior lip of the cervix was Cerclage placement was considered when the cervical grasped with the sponge stick. A Foley catheter was length was < 25 mm. Cervical lengths of 16–25 mm passed within the endocervical canal and its balloon was were considered as intermediately short and additional inflated with 30 mL of fluid to displace the membranes factors utilized to offer a cerclage included rate of from the operative site and avoid inadvertent membrane cervical shortening, progressive shortening within this puncture during suture placement. Two pieces of 0 range, history of prior spontaneous preterm birth or Prolene (Ethicon, Somerville, NJ, USA) were used with mid-trimester loss and gestational age at onset of cervical a CT needle, with placement begun at the first to shortening. A cervical length of ≤ 15 mm was a definitive second cervical–vaginal rugal folds at 12 o’clock. At our indicator for offering cerclage. The sonographic cervical institution, we use Prolene because