title: Nationwide Twin Birth Weight Percentiles by Gestational Age in Taiwan.
abstract: BACKGROUND
  Nationwide birth weight norms for twins have been reported in several countries across different ethnicities, but such data have not been established in Taiwan. The purpose of this study was to develop reference growth charts that are population-based and contain the information of birth weight percentiles by gestational age for twin neonates in Taiwan.
  
  
  METHODS
  In this study, we collected nationwide birth weight data for twins by sex and gestational age through the Taiwan Birth Registry. Percentiles, means, and standard deviations of birth weight for each 1-week increment of gestational age from 21 weeks of gestation were estimated and smoothed using weighted polynomial models.
  
  
  RESULTS
  The 10(th), 50(th), and 90(th) percentiles of birth weight born at the 37(th) gestational week were 2174 g, 2580 g, and 3125 g for male twins, respectively, and they were 2100 g, 2500 g, and 3000 g for female twins, respectively. The 10(th), 50(th), and 90(th) percentiles of birth weight born at the 40(th) gestational week were 2326, 3285, and 3790 g for male twins, respectively, and they were 2200 g, 2770 g, and 3690 g for female twins, respectively.
  
  
  CONCLUSIONS
  This is the first nationwide birth weight norm for twins in Taiwan, which is particularly useful for investigation into the predictors and outcomes of altered fetal growth through twin studies in the Taiwanese population.
authors: Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan; Department of Pediatrics, Taipei City Hospital, Taipei, Taiwan.
authors: I-Jan
authors: IJ
authors: Hu
authors: Department of Public Health, Tzu Chi University, Hualien, Taiwan.
authors: Chia-Jung
authors: CJ
authors: Hsieh
authors: School and Graduate Institute of Physical Therapy, National Taiwan University College of Medicine, Taipei, Taiwan.
authors: Suh-Fang
authors: SF
authors: Jeng
authors: Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University College of Public Health, Taipei, Taiwan.
authors: Hui-Chen
authors: HC
authors: Wu
authors: Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors: Chien-Yi
authors: CY
authors: Chen
authors: Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors: Hung-Chieh
authors: HC
authors: Chou
authors: Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors: Po-Nien
authors: PN
authors: Tsao
authors: Department of Pediatrics, Chi-Mei Hospital, Tainan, Taiwan.
authors: Shio-Jean
authors: SJ
authors: Lin
authors: Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University College of Public Health, Taipei, Taiwan; Department of Public Health, National Taiwan University College of Public Health, Taipei, Taiwan; Department of Environmental and Occupational Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan. Electronic address: pchen@ntu.edu.tw.
authors: Pau-Chung
authors: PC
authors: Chen
authors: Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan. Electronic address: hsiehws@ntu.edu.tw.
authors: Wu-Shiun
authors: WS
authors: Hsieh
mesh_terms: D001724:Birth Weight; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D013624:Taiwan; D014427:Twins
keywords: birth weight; gestational age; intrauterine growth; percentile; twin