title: Reference curves of birth weight, length, and head circumference for gestational ages in Yogyakarta, Indonesia.
abstract: The birth weight reference curve to estimate the newborns at risk in need of assessment and monitoring has been established. The previous reference curves from Indonesia, approximately 8 years ago, were based on the data collected from teaching hospitals only with limited gestational ages. The aims of the study were to update the reference curves for birth weight, supine length and head circumference for Indonesia, and to compare birth weight curves of boys and girls, first child and later children, and the ones in the previous studies.
  
  
  
  Data were extracted from the Maternal-Perinatal database between 1998-2007. Only live singletons with recorded gestational ages of 26 to 42 weeks and the exact time of admission to the neonatal facilities delivered or referred within 24 h of age to Sardjito Hospital, five district hospitals and five health centers in Yogyakarta Special Territory were included. Newborns with severely ill conditions, congenital anomaly and chromosomal abnormality were excluded. Smoothening of the curves was accomplished using a third-order polynomial equation.
  
  
  
  Our study included 54,599 singleton live births. Growth curves were constructed for boys (53.3%) and girls (46.7%) for birth weight, supine length, and head circumference. At term, mean birth weight for each gestational age of boys was significantly higher than that of girls. While mean birth weight for each gestational age of first-born-children, on the other hand was significantly lower than that of later-born-children. The mean birth weight was lower than that of Lubchenco's study. Compared with the previous Indonesian study by Alisyahbana, no differences were observed for the aterm infants, but lower mean birth weight was observed in preterm infants.
  
  
  
  Updated neonatal reference curves for birth weight, supine length and head circumference are important to classify high risk newborns in specific area and to identify newborns requiring attention.
authors.affiliation: Department of Child Health, Faculty of Medicine, Gadjah Mada University, Sardjito General Hospital, Jl. Kesehatan No. 1, Yogyakarta, 55284, Indonesia. ekahaksari@yahoo.com.
authors.forename: Ekawaty L
authors.initials: EL
authors.lastname: Haksari
authors.affiliation: Department of Pediatrics, Vrije Universiteit Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
authors.forename: Harrie N
authors.initials: HN
authors.lastname: Lafeber
authors.affiliation: Faculty of Medicine, Gadjah Mada University/Sardjito General Hospital, Jl. Kesehatan No. 1, Yogyakarta, 55284, Indonesia.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Hakimi
authors.affiliation: Department of Child Health, Faculty of Medicine, Gadjah Mada University, Sardjito General Hospital, Jl. Kesehatan No. 1, Yogyakarta, 55284, Indonesia.
authors.forename: Endy P
authors.initials: EP
authors.lastname: Pawirohartono
authors.affiliation: Public Health and Clinical Medicine, Umeå University, SE-901 87, Umeå, Sweden.
authors.forename: Lennarth
authors.initials: L
authors.lastname: Nyström
mesh_terms: D001724:Birth Weight; D001827:Body Height; D002508:Cephalometry; D005260:Female; D005865:Gestational Age; D057238:Growth Charts; D006801:Humans; D007214:Indonesia; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D012016:Reference Values
keywords: Birth weight; First-later-born children; Head circumference; Preterm term; Reference curve; Sex; Supine length