title: Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a prospective longitudinal cohort study.
abstract: OBJECTIVE
  To describe patterns in maternal gestational weight gain (GWG) in healthy pregnancies with good maternal and perinatal outcomes.
  
  
  METHODS
  Prospective longitudinal observational study.
  
  
  METHODS
  Eight geographically diverse urban regions in Brazil, China, India, Italy, Kenya, Oman, United Kingdom, and United States, April 2009 to March 2014.
  
  
  METHODS
  Healthy, well nourished, and educated women enrolled in the Fetal Growth Longitudinal Study component of the INTERGROWTH-21(st) Project, who had a body mass index (BMI) of 18.50-24.99 in the first trimester of pregnancy.
  
  
  METHODS
  Maternal weight measured with standardised methods and identical equipment every five weeks (plus/minus one week) from the first antenatal visit (<14 weeks' gestation) to delivery. After confirmation that data from the study sites could be pooled, a multilevel, linear regression analysis accounting for repeated measures, adjusted for gestational age, was applied to produce the GWG values.
  
  
  RESULTS
  13,108 pregnant women at <14 weeks' gestation were screened, and 4607 met the eligibility criteria, provided consent, and were enrolled. The variance within sites (59.6%) was six times higher than the variance between sites (9.6%). The mean GWGs were 1.64 kg, 2.86 kg, 2.86 kg, 2.59 kg, and 2.56 kg for the gestational age windows 14-18(+6) weeks, 19-23(+6) weeks, 24-28(+6) weeks, 29-33(+6) weeks, and 34-40(+0) weeks, respectively. Total mean weight gain at 40 weeks' gestation was 13.7 (SD 4.5) kg for 3097 eligible women with a normal BMI in the first trimester. Of all the weight measurements, 71.7% (10,639/14,846) and 94.9% (14,085/14,846) fell within the expected 1 SD and 2 SD thresholds, respectively. Data were used to determine fitted 3rd, 10th, 25th, 50th, 75th, 90th, and 97th smoothed GWG centiles by exact week of gestation, with equations for the mean and standard deviation to calculate any desired centiles according to gestational age in exact weeks.
  
  
  CONCLUSIONS
  Weight gain in pregnancy is similar across the eight populations studied. Therefore, the standards generated in this study of healthy, well nourished women may be used to guide recommendations on optimal gestational weight gain worldwide.
authors.affiliation: Nuffield Department of Obstetrics & Gynaecology and Oxford Maternal & Perinatal Health Institute, Green Templeton College, University of Oxford, Oxford, UK leila.cheikhismail@obs-gyn.ox.ac.uk.
authors.forename: Leila
authors.initials: L
authors.lastname: Cheikh Ismail
authors.affiliation: Nuffield Department of Obstetrics & Gynaecology and Oxford Maternal & Perinatal Health Institute, Green Templeton College, University of Oxford, Oxford, UK.
authors.forename: Deborah C
authors.initials: DC
authors.lastname: Bishop
authors.affiliation: School of Public Health, Peking University, Beijing, China.
authors.forename: Ruyan
authors.initials: R
authors.lastname: Pang
authors.affiliation: Nuffield Department of Obstetrics & Gynaecology and Oxford Maternal & Perinatal Health Institute, Green Templeton College, University of Oxford, Oxford, UK Centre for Statistics in Medicine, Botnar Research Centre, University of Oxford, Oxford, UK.
authors.forename: Eric O
authors.initials: EO
authors.lastname: Ohuma
authors.affiliation: Universidade Federal do Rio de Janeiro/Rio de Janeiro Federal University, Instituto de Nutrição Josué de Castro/Nutrition Institute, Departamento de Nutrição Social e Aplicada, Rio de Janeiro, Brazil.
authors.forename: Gilberto
authors.initials: G
authors.lastname: Kac
authors.affiliation: School of Public Health, University of California, Berkeley, CA, USA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Abrams
authors.affiliation: Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Rasmussen
authors.affiliation: Programa de Pós-Graduação em Epidemiologia, Universidade Federal de Pelotas, Pelotas, RS, Brazil Programa de Pós-Graduação em Saúde e Comportamento, Universidade Católica de Pelotas, Pelotas, RS, Brazil.
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Barros
authors.affiliation: Nuffield Department of Obstetrics & Gynaecology and Oxford Maternal & Perinatal Health Institute, Green Templeton College, University of Oxford, Oxford, UK.
authors.forename: Jane E
authors.initials: JE
authors.lastname: Hirst
authors.affiliation: Nuffield Department of Obstetrics & Gynaecology and Oxford Maternal & Perinatal Health Institute, Green Templeton College, University of Oxford, Oxford, UK.
authors.forename: Ann
authors.initials: A
authors.lastname: Lambert
authors.affiliation: Nuffield Department of Obstetrics & Gynaecology and Oxford Maternal & Perinatal Health Institute, Green Templeton College, University of Oxford, Oxford, UK.
authors.forename: Aris T
authors.initials: AT
authors.lastname: Papageorghiou
authors.affiliation: Faculty of Health Sciences, Aga Khan University, Nairobi, Kenya School of Medicine, University of St Andrews, St Andrews, Scotland, UK.
authors.forename: William
authors.initials: W
authors.lastname: Stones
authors.affiliation: Department of Family and Community Health, Ministry of Health, Muscat, Sultanate of Oman.
authors.forename: Yasmin A
authors.initials: YA
authors.lastname: Jaffer
authors.affiliation: Centre for Statistics in Medicine, Botnar Research Centre, University of Oxford, Oxford, UK.
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Altman
authors.affiliation: Department of Engineering Science, University of Oxford, Oxford, UK.
authors.forename: J Alison
authors.initials: JA
authors.lastname: Noble
authors.affiliation: Direttore SC consultori familiari e pediatria di comunità, Torino, Italy.
authors.forename: Maria Rosa
authors.initials: MR
authors.lastname: Giolito
authors.affiliation: Global Alliance to Prevent Prematurity and Stillbirth (GAPPS), Seattle Children's, Seattle, WA, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Gravett
authors.affiliation: Nagpur INTERGROWTH-21 Research Centre, Ketkar Hospital, Nagpur, India.
authors.forename: Manorama
authors.initials: M
authors.lastname: Purwar
authors.affiliation: Nuffield Department of Obstetrics & Gynaecology and Oxford Maternal & Perinatal Health Institute, Green Templeton College, University of Oxford, Oxford, UK.
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Kennedy
authors.affiliation: Centre of Excellence in Women and Child Health, Aga Khan University, Karachi, Pakistan Centre for Global Child Health, Hospital for Sick Children, TN, Canada.
authors.forename: Zulfiqar A
authors.initials: ZA
authors.lastname: Bhutta
authors.affiliation: Nuffield Department of Obstetrics & Gynaecology and Oxford Maternal & Perinatal Health Institute, Green Templeton College, University of Oxford, Oxford, UK.
authors.forename: José
authors.initials: J
authors.lastname: Villar
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015992:Body Mass Index; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008423:Maternal Age; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D015430:Weight Gain / Q000502:physiology*