title: Concordance between self-reported pre-pregnancy body mass index (BMI) and BMI measured at the first prenatal study contact.
abstract: The 2009 Institute of Medicine (IOM) gestational weight recommendations are tailored to women's pre-pregnancy body mass index (BMI). Limited evidence exists on methods for estimating women's pre-pregnancy BMI, particularly for women living in low and middle income countries. Using data from collected among Peruvian pregnant women, we compared the concordance between self-reported pre-pregnancy BMI with BMI measured at the earliest prenatal study visit.
  
  
  
  Data were from the Pregnancy Outcomes Maternal and Infant Study (PrOMIS), a cohort of pregnant women at the Instituto Nacional Materno Perinatal (INMP) in Lima, Peru. 2605 women aged 18 to 49 years (mean ± SD gestational age = 10.9 ± 3.3 weeks) were included in the study. Self-reported pre-pregnancy weight and height and measured weight and height were collected at the first prenatal study contact. We assessed the concordance between measured and self-reported BMI; and, the agreement among indicators of nutritional status obtained using measured and self-reported BMI.
  
  
  
  On average, weight measured at the first prenatal study visit was 0.27 kg higher than self-reported pre-pregnancy weight (p < 0.05); and, measured height was 0.02 m lower than self-reported pre-pregnancy height (p < 0.001). Correspondingly, measured BMI was 0.71 kg/m(2) higher than self-reported BMI (p < 0.001). Scatter and Bland-Altman plots indicated strong concordance between measured and self-reported BMI. The proportion of women in the normal BMI category tended to be higher when using self-reported BMI (59.6 %) than when using measured BMI (50.4 %). Conversely, the proportion of women in the overweight or obese BMI categories tended to be lower when using self-reported BMI (38.2 %) than when using measured BMI (47.7 %).
  
  
  
  Self-reported pre-pregnancy BMI was strongly correlated with BMI measured at the first prenatal study contact. The findings potentially suggest that, in this context, there is minimal change between pre-pregnancy BMI and BMI measured at the first prenatal study contact; or, that women in this study just recalled their most recent measured anthropometrics (including values obtained during the index pregnancy but before enrollment in the PrOMIS study).
authors.affiliation: Department of Epidemiology, Harvard TH Chan School of Public Health, 677 Huntington Avenue, Kresge Room 500, Boston, MA, 02115, USA. natamba@hsph.harvard.edu.
authors.forename: Barnabas K
authors.initials: BK
authors.lastname: Natamba
authors.affiliation: Universidad Peruana de Ciencias Aplicadas, Lima, Peru.|Asociacion Civil Proyectos en Salud (PROESA), Lima, Peru.
authors.forename: Sixto E
authors.initials: SE
authors.lastname: Sanchez
authors.affiliation: Department of Epidemiology, Harvard TH Chan School of Public Health, 677 Huntington Avenue, Kresge Room 500, Boston, MA, 02115, USA.
authors.forename: Bizu
authors.initials: B
authors.lastname: Gelaye
authors.affiliation: Department of Epidemiology, Harvard TH Chan School of Public Health, 677 Huntington Avenue, Kresge Room 500, Boston, MA, 02115, USA.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Williams
mesh_terms: D000293:Adolescent; D000328:Adult; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D006801:Humans; D008875:Middle Aged; D009752:Nutritional Status; D010568:Peru; D011247:Pregnancy; D011295:Prenatal Care; D057566:Self Report; D055815:Young Adult
keywords: Concordance; Low- and middle–income country; Peru; Self-reported pre-pregnancy weight, height and BMI; South America; Weight, height, and BMI measured early during pregnancy