title: Dilatation and curettage increases the risk of subsequent preterm birth: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Could dilatation and curettage (D&C), used in the treatment of miscarriage and termination of pregnancy, increase the risk of subsequent preterm birth?
  
  
  CONCLUSIONS
  A history of curettage in women is associated with an increased risk of preterm birth in a subsequent pregnancy compared with women without such history.
  
  
  BACKGROUND
  D&C is one of the most frequently performed procedures in obstetrics and gynaecology. Apart from the acknowledged but relatively rare adverse effects, such as cervical tears, bleeding, infection, perforation of the uterus, bowel or bladder, or Asherman syndrome, D&C has been suggested to also lead to an increased risk of preterm birth in the subsequent pregnancy.
  
  
  METHODS
  In the absence of randomized data, we conducted a systematic review and meta-analysis of cohort and case-control studies.
  
  
  METHODS
  We searched OVID MEDLINE and OVID EMBASE form inception until 21 May 2014. We selected cohort and case-control studies comparing subsequent preterm birth in women who had a D&C for first trimester miscarriage or termination of pregnancy and a control group of women without a history of D&C.
  
  
  RESULTS
  We included 21 studies reporting on 1 853 017 women. In women with a history of D&C compared with those with no such history, the odds ratio (OR) for preterm birth <37 weeks was 1.29 (95% CI 1.17; 1.42), while for very preterm birth the ORs were 1.69 (95% CI 1.20; 2.38) for <32 weeks and 1.68 (95% CI 1.47; 1.92) for <28 weeks. The risk remained increased when the control group was limited to women with a medically managed miscarriage or induced abortion (OR 1.19, 95% CI 1.10; 1.28). For women with a history of multiple D&Cs compared with those with no D&C, the OR for preterm birth (<37 weeks) was 1.74 (95% CI 1.10; 2.76). For spontaneous preterm birth, the OR was 1.44 (95% CI 1.22; 1.69) for a history of D&C compared with no such history.
  
  
  CONCLUSIONS
  There were no randomized controlled trials comparing women with and without a history of D&C and subsequent preterm birth. As a consequence, confounding may be present since the included studies were either cohort or case-control studies, not all of which corrected the results for possible confounding factors.
  
  
  CONCLUSIONS
  This meta-analysis shows that D&C is associated with an increased risk of subsequent preterm birth. The increased risk in association with multiple D&Cs indicates a causal relationship. Despite the fact that confounding cannot be excluded, these data warrant caution in the use of D&C for miscarriage and termination of pregnancy, the more so since less invasive options are available.
  
  
  BACKGROUND
  This study was funded by ZonMw, a Dutch organization for Health Research and Development, project number 80-82310-97-12066.
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands m.lemmers@amc.uva.nl.
authors.forename: M
authors.initials: M
authors.lastname: Lemmers
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: M A C
authors.initials: MA
authors.lastname: Verschoor
authors.affiliation: Department of Obstetrics and Gynecology, Zaans Medisch Centrum, Koningin Julianaplein 58, 1502 DV Zaandam, The Netherlands.
authors.forename: A B
authors.initials: AB
authors.lastname: Hooker
authors.affiliation: Clinical research unit, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: B C
authors.initials: BC
authors.lastname: Opmeer
authors.affiliation: Medical library, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Limpens
authors.affiliation: Department of Obstetrics and Gynecology, VU Medical Centre, De Boelelaan 1117, 1081 HZ Amsterdam, The Netherlands.
authors.forename: J A F
authors.initials: JA
authors.lastname: Huirne
authors.affiliation: Department of Obstetrics and Gynecology, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: W M
authors.initials: WM
authors.lastname: Ankum
authors.affiliation: The Robinson Institute, School of Paediatrics and Reproductive Health, University of Adelaide, 5000 SA Adelaide, Australia.
authors.forename: B W M
authors.initials: BW
authors.lastname: Mol
mesh_terms: D000328:Adult; D004107:Dilatation and Curettage / Q000009:adverse effects* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology / Q000209:etiology*
keywords: dilatation and curettage; expectant management; miscarriage; misoprostol; preterm birth; termination of pregnancy