title: Cross-sectional study of weight gain and increase in BMI throughout pregnancy.
abstract: OBJECTIVE
  To generate reliable new reference ranges for weight gain and increase in body mass index (BMI) during pregnancy from a large population.
  
  
  METHODS
  In a prospective cross-sectional study at the Obstetric outpatient clinic, Zurich University Hospital, weight gain and BMI, before gestation and at the booking visit, were determined in 4034 pregnant women with accurately dateable singleton pregnancies (Caucasian: N = 3242, Asian (predominantly from Sri Lanka, Thailand and the Philippines): N = 578 and Black: N = 214). Women with known insulin-dependent diabetes mellitus before pregnancy were excluded. Fifth, 50th and 95th centiles were presented for Caucasians and corresponding centile curves for Asians and Blacks. Simple and multiple regression analyses were performed for various risk factors. A significance level of P < 0.05 was used in all tests.
  
  
  RESULTS
  Mean weight gain was 15.5+/-5.9 kg (34.2+/-13.0 lb) at term with values >25.4 kg (56.0 lb) and <5.7 kg (12.6 lb) for the 95th and the 5th centile, respectively. Mean BMI increased slightly and steadily to 28 kgm(-2) at term. Parity and pre-pregnancy BMI were significant determinants in Caucasians. Weight gain and BMI was slightly lower in Asians and Blacks.
  
  
  CONCLUSIONS
  BMI centile curves have the advantage in that they consider height during the whole course of pregnancy. It may be an additional helpful tool in controlling weight gain in pregnancy. Further studies are required to determine the prognostic implications of values > or = 95th centile and < or = 5th centile.
authors.affiliation: Obstetric Research Unit, Department of Obstetrics, University Hospital, Frauenklinikstr. 10, CH-8091 Zurich, Switzerland. nicole.ochsenbein@usz.ch
authors.forename: Nicole
authors.initials: N
authors.lastname: Ochsenbein-Kölble
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Roos
authors.forename: Theo
authors.initials: T
authors.lastname: Gasser
authors.forename: Roland
authors.initials: R
authors.lastname: Zimmermann
mesh_terms: D000328:Adult; D000886:Anthropometry; D044466:Asian People; D044383:Black People; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D011247:Pregnancy / Q000502:physiology*; D012016:Reference Values; D013557:Switzerland / Q000208:ethnology; D015430:Weight Gain / Q000208:ethnology; D044465:White People