title: Medication abortion failure in women with and without previous cesarean delivery.
abstract: OBJECTIVE
  To investigate the association between previous cesarean delivery and medication abortion failure and the association between parity and failure.
  
  
  METHODS
  Data were abstracted from 2035 consecutive charts of women who underwent medication abortion in 2011. All women were at 63 days gestation or less and received mifepristone 200mg orally and misoprostol 800 mcg buccally. We used multivariate logistic regression to assess the relationship between failure, defined as requiring either curettage or additional medication, and prior cesarean delivery. We also examined the relationship between failure and parity.
  
  
  RESULTS
  Follow-up was available on 1609 (79%) patients. Overall, 4.5% of patients experienced failure. Neither cesarean delivery nor parity was associated with failure; 6.5% of women with prior cesarean delivery experienced failure, compared to 3.7% of nulliparous women [adjusted odds ratio (aOR), 1.79, 95% confidence interval (CI), 0.83-3.87]. With regard to parity, 4.7% of women with two or more previous births experienced failure, compared to 3.7% of nulliparous women (aOR, 1.07, 95% CI, 0.54-2.14).
  
  
  CONCLUSIONS
  We did not find significant associations between prior cesarean delivery and failure or parity and failure. A previous study of patients who had received a less effective regimen reported significant associations between cesarean delivery and failure and parity and failure. While our results do not rule out the possibility of modest associations due to our limited statistical power, they are reassuring relative to previous findings.
  
  
  CONCLUSIONS
  Our results suggest that if there are differences in women's odds of medication abortion failure by obstetric history, such differences are unlikely to be large. Providers and patients may factor this information into decision making about methods of pregnancy termination.
authors.affiliation: University of California, San Francisco, Department of Family & Community Medicine, 1001 Potrero Ave., San Francisco, CA, USA 94110; University of California, San Francisco, Department of Obstetrics, Gynecology & Reproductive Sciences; University of California, San Francisco, Department of Epidemiology & Biostatistics. Electronic address: christine.dehlendorf@ucsf.edu.
authors.forename: Christine E
authors.initials: CE
authors.lastname: Dehlendorf
authors.affiliation: University of California, San Francisco, Department of Family & Community Medicine, 1001 Potrero Ave., San Francisco, CA, USA 94110.
authors.forename: Edith E
authors.initials: EE
authors.lastname: Fox
authors.affiliation: Family Planning Associates Medical Group.
authors.forename: Rose F
authors.initials: RF
authors.lastname: Ali
authors.affiliation: University of California, San Francisco, Department of Family & Community Medicine, 1001 Potrero Ave., San Francisco, CA, USA 94110.
authors.forename: Nora C
authors.initials: NC
authors.lastname: Anderson
authors.affiliation: University of California, San Francisco, Department of Family & Community Medicine, 1001 Potrero Ave., San Francisco, CA, USA 94110.
authors.forename: Reiley D
authors.initials: RD
authors.lastname: Reed
authors.affiliation: Family Planning Associates Medical Group; Northwestern University Feinberg School of Medicine.
authors.forename: E Steve
authors.initials: ES
authors.lastname: Lichtenberg
mesh_terms: D000019:Abortifacient Agents; D000028:Abortion, Induced / Q000009:adverse effects*; D000293:Adolescent; D000328:Adult; D002585:Cesarean Section / Q000009:adverse effects*; D005260:Female; D006801:Humans; D016015:Logistic Models; D015735:Mifepristone; D016595:Misoprostol; D010298:Parity; D011247:Pregnancy; D012189:Retrospective Studies; D017211:Treatment Failure; D055815:Young Adult
chemical_list: D000019:Abortifacient Agents; D016595:Misoprostol; D015735:Mifepristone
keywords: Abortion; Cesarean; Failure; Medication abortion; Parity