title: Self-reported pre-pregnancy weight versus weight measured at first prenatal visit: effects on categorization of pre-pregnancy body mass index.
abstract: To compare classification of pre-pregnancy body mass index (BMI) using self-reported pre-pregnancy weight versus weight measured at the first prenatal visit. Retrospective cohort of 307 women receiving prenatal care at the faculty and resident obstetric clinics at a Massachusetts tertiary-care center. Eligible women initiated prenatal care prior to 14 weeks gestation and delivered singleton infants between April 2007 and March 2008. On average, self-reported weight was 4 pounds lighter than measured weight at the first prenatal visit (SD 7.2 pounds; range: 19 pounds lighter to 35 pounds heavier). Using self-reported pre-pregnancy weight to calculate pre-pregnancy BMI, 4.2 % of women were underweight, 48.9 % were normal weight, 25.4 % were overweight, and 21.5 % were obese. Using weight measured at first prenatal visit, these were 3.6, 45.3, 26.4, and 24.8 %, respectively. Classification of pre-pregnancy BMI was concordant for 87 % of women (weighted kappa = 0.86; 95 % CI 0.81-0.90). Women gained an average of 32.1 pounds (SD 18.0 pounds) during pregnancy. Of the 13 % of the sample with discrepant BMI classification, 74 % gained within the same adherence category when comparing weight gain to Institute of Medicine recommendations. For the vast majority of women, self-reported pre-pregnancy weight and measured weight at first prenatal visit resulted in identical classification of pre-pregnancy BMI. In absence of measured pre-pregnancy weight, we recommend that providers calculate both values and discuss discrepancies with their pregnant patients, as significant weight loss or gain during the first trimester may indicate a need for additional oversight with potential intervention.
authors.affiliation: Department of Obstetrics and Gynecology, University of Massachusetts Medical School/University of Massachusetts Memorial Health Care, 119 Belmont Street, Jaquith Building, Worcester, MA, 01605, USA, erica.holland@umassmed.edu.
authors.forename: Erica
authors.initials: E
authors.lastname: Holland
authors.forename: Tiffany A
authors.initials: TA
authors.lastname: Moore Simas
authors.forename: Darrah K
authors.initials: DK
authors.lastname: Doyle Curiale
authors.forename: Xun
authors.initials: X
authors.lastname: Liao
authors.forename: Molly E
authors.initials: ME
authors.lastname: Waring
mesh_terms: D000328:Adult; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D006801:Humans; D008404:Massachusetts; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D011295:Prenatal Care / Q000379:methods*; D012189:Retrospective Studies; D012307:Risk Factors; D057566:Self Report; D015430:Weight Gain