title: The effect of a very short interpregnancy interval and pregnancy outcomes following a previous pregnancy loss.
abstract: OBJECTIVE
  We sought to assess the relationship between a short interpregnancy interval (IPI) following a pregnancy loss and subsequent live birth and pregnancy outcomes.
  
  
  METHODS
  A secondary analysis of women enrolled in the Effects of Aspirin in Gestation and Reproduction trial with a human chorionic gonadotropin-positive pregnancy test and whose last reproductive outcome was a loss were included in this analysis (n = 677). IPI was defined as the time between last pregnancy loss and last menstrual period of the current pregnancy and categorized by 3-month intervals. Pregnancy outcomes include live birth, pregnancy loss, and any pregnancy complications. These were compared between IPI groups using multivariate relative risk estimation by Poisson regression.
  
  
  RESULTS
  Demographic characteristics were similar between IPI groups. The mean gestational age of prior pregnancy loss was 8.6 ± 2.8 weeks. The overall live birth rate was 76.5%, with similar live birth rates between those with IPI ≤3 months as compared to IPI >3 months (adjusted relative risk [aRR], 1.07; 95% confidence interval [CI], 0.98-1.16). Rates were also similar for periimplantation loss (aRR, 0.95; 95% CI, 0.51-1.80), clinically confirmed loss (aRR, 0.75; 95% CI, 0.51-1.10), and any pregnancy complication (aRR, 0.88; 95% CI, 0.71-1.09) for those with IPI ≤3 months as compared to IPI >3 months.
  
  
  CONCLUSIONS
  Live birth rates and adverse pregnancy outcomes, including pregnancy loss, were not associated with a very short IPI after a prior pregnancy loss. The traditional recommendation to wait at least 3 months after a pregnancy loss before attempting a new pregnancy may not be warranted.
authors.affiliation: Department of Obstetrics and Gynecology, University of Utah School of Medicine, and Department of Maternal-Fetal Medicine, Intermountain Healthcare, Salt Lake City, UT. Electronic address: luchin.wong@hsc.utah.edu.
authors.forename: Luchin F
authors.initials: LF
authors.lastname: Wong
authors.affiliation: Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD.
authors.forename: Karen C
authors.initials: KC
authors.lastname: Schliep
authors.affiliation: Department of Obstetrics and Gynecology, University of Utah School of Medicine, and Department of Maternal-Fetal Medicine, Intermountain Healthcare, Salt Lake City, UT.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Silver
authors.affiliation: Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD.
authors.forename: Sunni L
authors.initials: SL
authors.lastname: Mumford
authors.affiliation: Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD.
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Perkins
authors.affiliation: Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD.
authors.forename: Aijun
authors.initials: A
authors.lastname: Ye
authors.affiliation: Department of Statistics, University of Haifa, Haifa, Israel.
authors.forename: Noya
authors.initials: N
authors.lastname: Galai
authors.affiliation: Department of Epidemiology and Environmental Health, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY.
authors.forename: Jean
authors.initials: J
authors.lastname: Wactawski-Wende
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, University of Colorado, Denver, CO.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Lynch
authors.affiliation: Department of Family, Community, and Rural Health, Commonwealth Medical College, Scranton, PA.
authors.forename: Janet M
authors.initials: JM
authors.lastname: Townsend
authors.affiliation: Department of Statistics, University of Haifa, Haifa, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Faraggi
authors.affiliation: Epidemiology Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD.
authors.forename: Enrique F
authors.initials: EF
authors.lastname: Schisterman
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology / Q000209:etiology*; D000293:Adolescent; D000328:Adult; D001721:Birth Intervals; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D050498:Live Birth / Q000453:epidemiology*; D015999:Multivariate Analysis; D016012:Poisson Distribution; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology / Q000209:etiology; D011256:Pregnancy Outcome; D012044:Regression Analysis; D014481:United States; D055815:Young Adult
keywords: interpregnancy interval; miscarriage; pregnancy loss; pregnancy outcomes; spontaneous abortion