title: Prepregnancy Low to Moderate Alcohol Intake Is Not Associated with Risk of Spontaneous Abortion or Stillbirth.
abstract: BACKGROUND
  Numerous studies have documented the negative effects of maternal alcohol consumption during pregnancy on risk of pregnancy loss, yet whether prepregnancy alcohol intake affects the risk of spontaneous abortion is still unclear.
  
  
  OBJECTIVE
  This study aimed to assess prepregnancy alcohol intake and risk of spontaneous abortion and stillbirth.
  
  
  METHODS
  Our prospective cohort study included 27,580 pregnancies reported by 17,929 women in the Nurses' Health Study II between 1990 and 2009. Alcohol intake was assessed in 1989 and 1991 and every 4 y thereafter with the use of a validated questionnaire. Women were classified into 5 categories of consumption: 0, 0.1-1.9, 2-4.9, 5-9.9, and ≥10 g/d (1 serving = ∼12 g). Pregnancies were self-reported, with case pregnancies lost spontaneously (spontaneous abortion after gestation of <20 wk and stillbirth after gestation of ≥20 wk) and comparison pregnancies not ending in fetal loss (live birth, ectopic pregnancy, or induced abortion). Multivariable log-binomial regression models with generalized estimating equations were used to estimate RRs and 95% CIs.
  
  
  RESULTS
  Incident spontaneous abortion and stillbirth were reported in 4326 (15.7%) and 205 (0.7%) pregnancies, respectively. Prepregnancy alcohol intake was not associated with spontaneous abortion. Compared with women who did not consume alcohol, the multivariable RRs (95% CIs) for increasing categories of alcohol intake among women who did consume alcohol were 1.04 (0.97, 1.12) for 0.1-1.9 g/d, 1.02 (0.94, 1.11) for 2-4.9 g/d, 1.01 (0.92, 1.10) for 5-9.9 g/d, and 0.98 (0.88, 1.09) for ≥10 g/d (P-trend = 0.45). Women who consumed ≥2 servings beer/wk before pregnancy had a 9% (95% CI: 1%, 17%) lower risk of spontaneous abortion than did women who consumed <1 serving beer/mo; however, this association did not persist in various sensitivity analyses. Prepregnancy consumption of wine and liquor were not associated with spontaneous abortion. Total alcohol and specific alcohol beverage intake before pregnancy were not associated with stillbirth.
  
  
  CONCLUSIONS
  Prepregnancy alcohol intake was not related to risk of incident spontaneous abortion or stillbirth in women with no history of pregnancy loss. Our results provide reassuring evidence that low to moderate alcohol intake (≤12 g/d) before pregnancy initiation does not affect risk of pregnancy loss.
authors.affiliation: Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA.
authors.forename: Audrey J
authors.initials: AJ
authors.lastname: Gaskins
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA.|Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.|Connors Center for Women's Health and Gender Biology, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
authors.forename: Janet W
authors.initials: JW
authors.lastname: Rich-Edwards
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA.|Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA.
authors.forename: Paige L
authors.initials: PL
authors.lastname: Williams
authors.affiliation: Vincent Obstetrics and Gynecology, Massachusetts General Hospital and Harvard Medical School, Boston, MA.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Toth
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA.|Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.|Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.|Department of Obstetrics, Gynecology and Reproductive Biology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Stacey A
authors.initials: SA
authors.lastname: Missmer
authors.affiliation: Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA.|Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Chavarro
keywords: alcohol; ethanol; miscarriage; pregnancy loss; spontaneous abortion; stillbirth