title: The relationship between unplanned pregnancy and maternal body mass index 2009-2012.
abstract: OBJECTIVE
  To analyse the relationship between unplanned pregnancy and maternal Body Mass Index (BMI).
  
  
  METHODS
  A prospective case-control study of planned vs. unplanned pregnancies among women who delivered an infant weighing ≥ 500 g during the four years 2009-2012 in a large maternity hospital in Ireland. Maternal weight and height were measured at the first antenatal visit before calculation of BMI. Clinical and sociodemographic details were computerised. BMI was categorised according to the World Health Organization. The epidemiological associations were examined using logistic regression, adjusted for confounding variables.
  
  
  RESULTS
  Between 2009 and 2012, 34,377 women were included, 31.7% (n = 10,894) reported an unplanned pregnancy and 16.6% (n = 5647) were obese. The odds ratios of unplanned pregnancy were greater among obese women compared with those of normal BMI (unadjusted Odds Ratio (OR) 1.3; 95% Confidence Interval (CI) 1.3-1.4 p < 0.001). These ratios increased with increasing BMI (mild unadjusted OR 1.3; CI 1.2-1.4 p < 0.001; moderate unadjusted OR 1.4; CI 1.2-1.6 p < 0.001; severe obesity unadjusted OR 1.7; CI 1.4-2.0 p < 0.001). The higher rate of unplanned pregnancy among obese women was associated with a lower rate of contraception usage and a higher rate of contraceptive failure. Only 37.6% (n = 2112) of obese women took preconceptional folic acid to prevent neural tube defects compared with 46.1% (n = 8176) of women with a normal BMI (p < 0.001).
  
  
  CONCLUSIONS
  Higher rates of unplanned pregnancy among obese women compared with women with a normal BMI is associated with compromised prepregnancy care in this high-risk population.
authors.affiliation: a UCD Centre for Human Reproduction, Coombe Women and Infants University Hospital , Dublin , Ireland.
authors.forename: Aoife
authors.initials: A
authors.lastname: McKeating
authors.affiliation: a UCD Centre for Human Reproduction, Coombe Women and Infants University Hospital , Dublin , Ireland.
authors.forename: Amy
authors.initials: A
authors.lastname: O'Higgins
authors.affiliation: a UCD Centre for Human Reproduction, Coombe Women and Infants University Hospital , Dublin , Ireland.
authors.forename: Ciara
authors.initials: C
authors.lastname: Turner
authors.affiliation: a UCD Centre for Human Reproduction, Coombe Women and Infants University Hospital , Dublin , Ireland.
authors.forename: Léan
authors.initials: L
authors.lastname: McMahon
authors.affiliation: a UCD Centre for Human Reproduction, Coombe Women and Infants University Hospital , Dublin , Ireland.
authors.forename: Sharon R
authors.initials: SR
authors.lastname: Sheehan
authors.affiliation: a UCD Centre for Human Reproduction, Coombe Women and Infants University Hospital , Dublin , Ireland.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Turner
mesh_terms: D000328:Adult; D015992:Body Mass Index; D016022:Case-Control Studies; D003268:Contraception Behavior / Q000706:statistics & numerical data; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D009765:Obesity / Q000453:epidemiology*; D016742:Preconception Care; D011247:Pregnancy; D049168:Pregnancy, Unplanned; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D005492:Folic Acid
keywords: Contraception; Maternal obesity; Unplanned pregnancy