title: Risk factors for first trimester miscarriage--results from a UK-population-based case-control study.
abstract: OBJECTIVE
  The aim of this study was to examine the association between biological, behavioural and lifestyle risk factors and risk of miscarriage.
  
  
  METHODS
  Population-based case-control study.
  
  
  METHODS
  Case-control study nested within a population-based, two-stage postal survey of reproductive histories of women randomly sampled from the UK electoral register.
  
  
  METHODS
  Six hundred and three women aged 18-55 years whose most recent pregnancy had ended in first trimester miscarriage (<13 weeks of gestation; cases) and 6116 women aged 18-55 years whose most recent pregnancy had progressed beyond 12 weeks (controls).
  
  
  METHODS
  Women were questioned about socio-demographic, behavioural and other factors in their most recent pregnancy.
  
  
  METHODS
  First trimester miscarriage.
  
  
  RESULTS
  After adjustment for confounding, the following were independently associated with increased risk: high maternal age; previous miscarriage, termination and infertility; assisted conception; low pre-pregnancy body mass index; regular or high alcohol consumption; feeling stressed (including trend with number of stressful or traumatic events); high paternal age and changing partner. Previous live birth, nausea, vitamin supplementation and eating fresh fruits and vegetables daily were associated with reduced risk, as were feeling well enough to fly or to have sex. After adjustment for nausea, we did not confirm an association with caffeine consumption, smoking or moderate or occasional alcohol consumption; nor did we find an association with educational level, socio-economic circumstances or working during pregnancy.
  
  
  CONCLUSIONS
  The results confirm that advice to encourage a healthy diet, reduce stress and promote emotional wellbeing might help women in early pregnancy (or planning a pregnancy) reduce their risk of miscarriage. Findings of increased risk associated with previous termination, stress, change of partner and low pre-pregnancy weight are noteworthy, and we recommend further work to confirm these findings in other study populations.
authors.affiliation: Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, UK. noreen.maconochie@lshtm.ac.uk
authors.forename: N
authors.initials: N
authors.lastname: Maconochie
authors.forename: P
authors.initials: P
authors.lastname: Doyle
authors.forename: S
authors.initials: S
authors.lastname: Prior
authors.forename: R
authors.initials: R
authors.lastname: Simmons
mesh_terms: D000022:Abortion, Spontaneous / Q000209:etiology*; D000293:Adolescent; D000328:Adult; D000428:Alcohol Drinking; D001835:Body Weight; D016022:Case-Control Studies; D004032:Diet; D004651:Employment; D005220:Fathers; D005260:Female; D015438:Health Behavior; D006801:Humans; D008019:Life Style; D008423:Maternal Age; D008603:Mental Health; D008875:Middle Aged; D010331:Paternal Age; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D017584:Reproductive History; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D012959:Socioeconomic Factors