title: Pessary placement in the prevention of preterm birth in multiple pregnancies: a propensity score analysis.
abstract: OBJECTIVE
  In asymptomatic women with a multiple pregnancy and short cervix prophylactic use of a cervical pessary might reduce preterm birth. We assessed the possible treatment effects of pessary use in pregnancy duration and for poor perinatal outcome.
  
  
  METHODS
  This cohort study was performed between December 2012 and September 2014 in 44 hospitals in the Netherlands. Women with multiple pregnancy had a cervical length measurement between 16 and 22 weeks of gestation. When cervical length was below 38 mm, women were offered a cervical pessary. The course of pregnancy, including perinatal outcome in these women was compared to the outcome of women from the placebo group of the AMPHIA trial (ISRCTN40512715) (historical cohort). Propensity-score matching with replacement was used to create comparable baseline characteristics between both populations.
  
  
  RESULTS
  We studied 63 women in the pessary group and 56 women as controls. Propensity-score matching generated 57 women in the intervention group matched to 57 women (31 unique) in the control group. Gestational age at delivery was comparable between both groups (HR 0.96, 95%-CI 0.46-1.46) as well as their delivery rates before 28, 32 and 37 weeks, RR 0.68 (95%-CI 0.21-2.18), RR 0.54 (95%-CI 0.21-1.41), and RR 1.22 (95%-CI 0.47-3.15), respectively. There was no difference in composite perinatal outcome (RR 1.36, 95%-CI 0.53-3.51) and perinatal mortality (RR 0.89, 95%-CI 0.24-3.38) either.
  
  
  CONCLUSIONS
  In this cohort study with propensity score analysis, pessary use did not prevent preterm birth in asymptomatic women with a multiple pregnancy and short cervix.
authors.affiliation: Department of Obstetrics and Gynaecology, Zuyderland Medical Center, Heerlen, The Netherlands. Electronic address: mjmmonfrance@gmail.com.
authors.forename: Maurice J M
authors.initials: MJ
authors.lastname: Monfrance
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands; Department of Obstetrics and Gynaecology, Academic Medical Center, Amsterdam, The Netherlands; Stanford Prevention Research Center, Stanford University, Stanford, CA, USA.
authors.forename: Ewoud
authors.initials: E
authors.lastname: Schuit
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Rolf H
authors.initials: RH
authors.lastname: Groenwold
authors.affiliation: Department of Obstetrics and Gynaecology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Martijn A
authors.initials: MA
authors.lastname: Oudijk
authors.affiliation: Department of Obstetrics and Gynaecology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Irene M
authors.initials: IM
authors.lastname: de Graaf
authors.affiliation: Department of Obstetrics and Gynaecology, VU Medical Center, Amsterdam, The Netherlands.
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Bax
authors.affiliation: Department of Obstetrics and Gynaecology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
authors.forename: Dick J
authors.initials: DJ
authors.lastname: Bekedam
authors.affiliation: Department of Obstetrics and Gynaecology, Academic Medical Center, Amsterdam, The Netherlands; The Robinson Institute, School of Pediatrics and Reproductive Health, University of Adelaide, Adelaide, Australia.
authors.forename: Ben Willem
authors.initials: BW
authors.lastname: Mol
authors.affiliation: Department of Obstetrics and Gynaecology, Zuyderland Medical Center, Heerlen, The Netherlands.
authors.forename: Josje
authors.initials: J
authors.lastname: Langenveld
mesh_terms: D000328:Adult; D058070:Asymptomatic Diseases; D001997:Bronchopulmonary Dysplasia / Q000453:epidemiology; D002543:Cerebral Hemorrhage / Q000453:epidemiology; D054791:Cervical Length Measurement; D015331:Cohort Studies; D020345:Enterocolitis, Necrotizing / Q000453:epidemiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000453:epidemiology; D007235:Infant, Premature, Diseases / Q000453:epidemiology; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data; D009426:Netherlands; D066087:Perinatal Death; D010570:Pessaries; D011247:Pregnancy; D011272:Pregnancy, Multiple; D059286:Pregnancy, Triplet; D059285:Pregnancy, Twin; D047928:Premature Birth / Q000517:prevention & control*; D057216:Propensity Score; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012127:Respiratory Distress Syndrome, Newborn / Q000453:epidemiology; D018805:Sepsis / Q000453:epidemiology; D050497:Stillbirth / Q000453:epidemiology
keywords: Multiple pregnancy; Pessary; Preterm birth; Propensity score; Short cervix