title: Prospective evaluation of the impact of intermenstrual bleeding on natural fertility.
abstract: OBJECTIVE
  To evaluate the impact of an episode of intermenstrual bleeding on the probability of conception in a menstrual cycle (fecundability).
  
  
  METHODS
  Prospective, time-to-pregnancy cohort study.
  
  
  METHODS
  Community-based cohort.
  
  
  METHODS
  Women trying to conceive, ages 30 to 44 years, without known infertility.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Current cycle and subsequent cycle fecundability.
  
  
  RESULTS
  A total of 549 women provided 1,552 complete cycles for analysis. Intermenstrual and luteal bleeding were reported in 36% and 34% of cycles, respectively. Ninety-three percent of all intermenstrual bleeding was luteal. Cycles in which women had intermenstrual bleeding or luteal bleeding were statistically significantly less likely to result in conception (fecundability ratio [FR] 0.23; 95% confidence interval [CI], 0.16-0.34; and FR 0.22; 95% CI, 0.14-0.33). Women with an episode of intermenstrual and luteal bleeding had a statistically significant increase in the probability of pregnancy in the subsequent cycle (FR 1.61; 95% CI, 1.15-2.25; and FR 2.01; 95% CI, 1.52-2.87, respectively).
  
  
  CONCLUSIONS
  Intermenstrual bleeding statistically significantly decreases the odds of conceiving in that cycle but does not appear to negatively impact a woman's immediate future reproductive potential.
  
  
  BACKGROUND
  NCT01028365.
authors.affiliation: Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina. Electronic address: natalie_crawford@med.unc.edu.
authors.forename: Natalie M
authors.initials: NM
authors.lastname: Crawford
authors.affiliation: Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: David A
authors.initials: DA
authors.lastname: Pritchard
authors.affiliation: Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: Amy H
authors.initials: AH
authors.lastname: Herring
authors.affiliation: Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: Anne Z
authors.initials: AZ
authors.lastname: Steiner
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D005298:Fertility / Q000502:physiology*; D006801:Humans; D008597:Menstrual Cycle / Q000097:blood*; D008796:Metrorrhagia / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D061685:Time-to-Pregnancy / Q000502:physiology*
keywords: Bleeding; fecundability; intermenstrual bleeding; luteal bleeding; natural fertility
references.citation: Am J Epidemiol. 2012 Mar 15;175(6):536-45
references.pmid: 22350580
references.citation: Am J Epidemiol. 2011 Sep 15;174(6):701-9
references.pmid: 21719742
references.citation: Fertil Steril. 2012 Nov;98(5):1112-7
references.pmid: 22819186
references.citation: Fertil Steril. 2013 Jan;99(1):279-85
references.pmid: 22999798
references.citation: J Clin Endocrinol Metab. 2014 Jun;99(6):E1007-14
references.pmid: 24606080
references.citation: Am J Obstet Gynecol. 2014 Oct;211(4):358.e1-6
references.pmid: 24799313
references.citation: Fertil Steril. 2002 Feb;77(2):337-41
references.pmid: 11821093
references.citation: Hum Reprod Update. 2002 Jan-Feb;8(1):60-7
references.pmid: 11866241
references.citation: Epidemiology. 2002 Nov;13(6):668-74
references.pmid: 12410008
references.citation: Maturitas. 2003 May 30;45(1):1-14
references.pmid: 12753939
references.citation: JAMA. 1968 Feb 5;203(6):377-80
references.pmid: 5694118
references.citation: Int J Fertil. 1987 Sep-Oct;32(5):359-65
references.pmid: 2889681
references.citation: N Engl J Med. 1988 Jul 28;319(4):189-94
references.pmid: 3393170
references.citation: Epidemiol Rev. 1995;17(2):265-86
references.pmid: 8654511
references.citation: Hum Reprod. 1998 Feb;13(2):403-8
references.pmid: 9557847
references.citation: N Engl J Med. 1999 Jun 10;340(23):1796-9
references.pmid: 10362823
references.citation: J Am Med Assoc. 1949 Dec 17;141(16):1123-9, illust
references.pmid: 15394678
references.citation: Hum Reprod. 2007 Mar;22(3):853-7
references.pmid: 17071824
references.citation: Fertil Steril. 2008 Jan;89(1):1-16
references.pmid: 18155200
references.citation: Fertil Steril. 2008 Nov;90(5 Suppl):S125-30
references.pmid: 19007608
references.citation: Paediatr Perinat Epidemiol. 2010 Jan;24(1):24-30
references.pmid: 20078826
references.citation: Obstet Gynecol. 2010 Aug;116(2 Pt 1):419-28
references.pmid: 20664404
references.citation: Fertil Steril. 2011 Feb;95(2):617-20
references.pmid: 20537624
references.citation: J Assist Reprod Genet. 2011 Apr;28(4):379-82
references.pmid: 21222029
references.citation: Clin Endocrinol (Oxf). 2012 Oct;77(4):500-7
references.pmid: 22702226