title: The protein source in embryo culture media influences birthweight: a comparative study between G1 v5 and G1-PLUS v5.
abstract: OBJECTIVE
  Does protein source or human serum albumin (HSA) in embryo culture media influence the subsequent birthweight?
  
  
  CONCLUSIONS
  A significant difference was observed in gestational age- and gender-adjusted birthweight (Z scores) and the proportion of large-for-gestational age (LGA) babies between embryos cultured in G1 v5 and those cultured in G1-PLUS v5 media.
  
  
  BACKGROUND
  It has been reported that the birthweights of singletons born from embryos cultured in Vitrolife are significantly higher than those cultured in the Cook group of media, and that G1-PLUS (Vitrolife, Gothenburg, Sweden) is associated with increased birth and placenta weights compared with Medicult ISMI.
  
  
  METHODS
  This study was a retrospective analysis of neonatal birthweights, and included 1097 singletons born from fresh embryo transfer cycles at the Center for Reproductive Medicine of Peking University Third Hospital between January 2011 and August 2012. The number of singletons born from G1 v5 culture media was 489, and the number of singletons born from G1-PLUS v5 media was 608.
  
  
  METHODS
  Patients <40 years of age with a BMI <30 kg/m² were analysed. Only data from newborns from singleton pregnancies and born alive after the 28th week of gestation were included. Patients with a vanishing twin or with pregnancy-related complications, such as diabetes and hypertension, were excluded, as were patients who received preimplantation genetic diagnosis or used donor oocytes. Multiple linear regression analysis was performed to determine the influence of individual factors on birthweights of singleton newborns. The birthweights and Z scores of singletons and LGA babies were compared between the G1 v5 and G1-PLUS v5 media groups.
  
  
  RESULTS
  The absolute birthweights for singletons resulting from G1-PLUS v5 were not different from singletons resulting from G1 v5 (3375.9 ± 479.6 g versus 3333.2 ± 491.6 g, respectively; P = 0.14). However the Z scores for singletons from embryos cultured in G1-PLUS v5 were significantly higher than for singletons cultured in G1 v5 (0.28 ± 1.12 versus 0.09 ± 1.15, respectively; P = 0.04), and more LGA babies were born from G1-PLUS v5 culture compared with G1 v5 (16.8 versus 12.1%, respectively; P = 0.03) culture. Finally, multiple linear regression analysis suggested that female weight (P = 0.00), male height (P = 0.04), gestational age at birth (P = 0.00), infant gender (P = 0.00) and culture media (P = 0.04) all had significant effects on the birthweights of singleton newborns.
  
  
  CONCLUSIONS
  This study was limited by its retrospective design.
  
  
  CONCLUSIONS
  Our study suggests that protein source/HSA has a significant effect on birthweights of singleton newborns.
  
  
  BACKGROUND
  This study was funded by the National Natural Science Foundation of China for Young Scholars (81300483). The authors have no conflicts of interest to declare.
  
  
  BACKGROUND
  Not applicable.
authors.forename: Jinliang
authors.initials: J
authors.lastname: Zhu
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Lixue
authors.initials: L
authors.lastname: Chen
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.forename: Jie
authors.initials: J
authors.lastname: Qiao
mesh_terms: D001724:Birth Weight; D015992:Body Mass Index; D003470:Culture Media / Q000737:chemistry*; D046149:Embryo Culture Techniques / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D016014:Linear Models; D008297:Male; D009929:Organ Size; D010920:Placenta / Q000502:physiology; D011247:Pregnancy; D011256:Pregnancy Outcome; D011506:Proteins / Q000737:chemistry*; D012189:Retrospective Studies; D012709:Serum Albumin / Q000032:analysis
chemical_list: D003470:Culture Media; D011506:Proteins; D012709:Serum Albumin