title: Induced abortions in women with rheumatoid arthritis receiving methotrexate.
abstract: OBJECTIVE
  To determine the rate of induced abortions in women with rheumatoid arthritis (RA) exposed to methotrexate (MTX) compared with women with RA unexposed to this medication.
  
  
  METHODS
  We performed a nested case-control study using administrative databases from Quebec. All women with RA ages 15-45 years were identified and cases were defined as women having an induced abortion. Each case was matched to ≥1 controls for age, calendar time, and cohort entry. Exposure was defined as having filled ≥1 prescriptions of MTX ≤16 weeks prior to the index date.
  
  
  RESULTS
  We identified 112 cases of induced abortions in women with RA and 5,855 RA controls. Exposure to MTX occurred in 10.7% of cases and 21.7% of controls. Women exposed to MTX had a lower rate of induced abortions compared with unexposed women (rate ratio [RR] 0.47 [95% confidence interval (95% CI) 0.25-0.89]). In the multivariate analysis, there was a trend toward an increased rate of induced abortions among women exposed to anti-tumor necrosis factor (anti-TNF) agents (RR 2.07 [95% CI 0.81-5.27]).
  
  
  CONCLUSIONS
  Women with RA exposed to MTX have a lower rate of induced abortions than unexposed women. Women with RA exposed to anti-TNF agents may have an increased rate of induced abortions compared to unexposed women.
authors.affiliation: McGill University Health Centre, Montreal, Quebec, Canada. evelyne.vinet@mail.mcgill.ca
authors.forename: Évelyne
authors.initials: É
authors.lastname: Vinet
authors.forename: Bindee
authors.initials: B
authors.lastname: Kuriya
authors.forename: Christian A
authors.initials: CA
authors.lastname: Pineau
authors.forename: Ann E
authors.initials: AE
authors.lastname: Clarke
authors.forename: Sasha
authors.initials: S
authors.lastname: Bernatsky
mesh_terms: D000020:Abortifacient Agents, Nonsteroidal / Q000009:adverse effects*; D000028:Abortion, Induced / Q000706:statistics & numerical data*; D000328:Adult; D001172:Arthritis, Rheumatoid / Q000188:drug therapy*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008727:Methotrexate / Q000009:adverse effects*; D015999:Multivariate Analysis; D011247:Pregnancy; D055815:Young Adult
chemical_list: D000020:Abortifacient Agents, Nonsteroidal; D008727:Methotrexate