title: A new population-based reference curve for symphysis-fundus height.
abstract: OBJECTIVE
  To present a new gestational-age-specific percentile curve for symphysis-fundus (SF) height and to determine the effects of maternal and fetal covariates.
  
  
  METHODS
  A population-based register study.
  
  
  METHODS
  Antenatal clinics in Västra Götaland County, Sweden, between 2005 and 2010.
  
  
  METHODS
  A total of 42 018 women with ultrasound-dated singleton pregnancies who delivered at Sahlgrenska University Hospital.
  
  
  METHODS
  Measurement of SF height.
  
  
  METHODS
  A non-linear regression of SF height on day of pregnancy was used to construct a reference chart for the median and other percentiles of SF height.
  
  
  RESULTS
  The new reference curve for SF height showed almost linear growth until term. The median value was considerably larger at each gestational age compared with the curves for SF height used in Norway and Denmark. Compared with the curve currently used in Sweden, higher median values were observed only at gestational ages >34 weeks, accompanied by an upward shift in all percentiles. The only notably influential covariates were maternal pre-pregnancy weight and height.
  
  
  CONCLUSIONS
  The new reference curve for SF height shows a pattern that is different from the Scandinavian reference curves of older origin, reflecting changes in the pregnant population, as well as methodological differences. The new curve can be adjusted for maternal and fetal covariates to suit individual pregnancies.
authors.affiliation: Women and Children's Division, Department of Obstetrics and Gynecology, Oslo University Hospital, Oslo, Norway. aase.pay@fhi.no
authors.forename: Aase Serine D
authors.initials: AS
authors.lastname: Pay
authors.forename: Jan Frederik
authors.initials: JF
authors.lastname: Frøen
authors.forename: Anne Cathrine
authors.initials: AC
authors.lastname: Staff
authors.forename: Bo
authors.initials: B
authors.lastname: Jacobsson
authors.forename: Håkon K
authors.initials: HK
authors.lastname: Gjessing
mesh_terms: D000328:Adult; D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D005260:Female; D005317:Fetal Growth Retardation / Q000175:diagnosis; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011631:Pubic Symphysis / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D012016:Reference Values; D012042:Registries; D013548:Sweden; D016216:Ultrasonography, Prenatal
keywords: Antenatal care; fetal growth restriction; low-risk pregnancy; reference curve; small-for-gestational-age; symphysis-fundus height measurement