title: The type of culture medium and the duration of in vitro culture do not influence birthweight of ART singletons.
abstract: OBJECTIVE
  Does the type of in vitro culture medium or the duration of in vitro culture influence singleton birthweight after IVF/ICSI treatment?
  
  
  CONCLUSIONS
  In a comparison of two culture media, neither the medium nor the duration of culture (Day 3 versus Day 5 blastocyst transfer) had any effect on mean singleton birthweight.
  
  
  BACKGROUND
  Previous studies indicated that in vitro culture of human embryos may affect birthweight of live born singletons. Both the type of culture medium and the duration of culture may be implicated. However, these studies are small and report conflicting results.
  
  
  METHODS
  A large retrospective analysis was performed including all singleton live births after transferring fresh Day 3 or Day 5 embryos. IVF and ICSI cycles performed between April 2004 and December 2009 at a tertiary care centre were included for analysis.
  
  
  METHODS
  A total of 2098 singleton live births resulting from singleton pregnancies were included for analysis. Two different sequential embryo culture media were concurrently used in an alternating way: Medicult (n = 1388) and Vitrolife (n = 710). Maternal age, maternal and paternal BMI, maternal parity, maternal smoking, main cause of infertility, cycle rank, stimulation protocol, method of fertilization (IVF or ICSI), time in culture and number of embryos transferred were taken into account. Embryo transfers were performed either on Day 3 (n = 1234) or on Day 5 (n = 864). Singleton birthweight was the primary outcome parameter. Gestational age and gender of the newborn were accounted for in the multiple regression analysis.
  
  
  RESULTS
  No significant differences in mean singleton birthweight were observed between the two culture media: Medicult 3222 g (±15 SE) and Vitrolife 3251 g (±21 SE) (P = 0.264). The mean singleton birthweight was not different between Day 3 embryo transfers (3219 ± 16 g) and Day 5 blastocyst transfers (3250 ± 19 g; P = 0.209). Multiple regression analysis controlling for potential maternal, paternal, treatment and newborn confounders confirmed the non-significant differences in mean singleton birthweight between the two culture media. Likewise, the adjusted mean singleton birthweight was not different according to the duration of in vitro culture (P = 0.521).
  
  
  CONCLUSIONS
  The conclusions are limited by its retrospective design; however, the two different sequential culture systems were used in an alternating way during the same time period. Pregnancy-associated factors possibly influencing birthweight (such as diabetes, hypertension, pre-eclampsia) were not included in the analysis.
  
  
  CONCLUSIONS
  This large retrospective study does not support earlier concerns that both the type of culture medium and the duration of embryo culture influence singleton birthweight. However, a continuous surveillance of human embryo culture procedures (medium type, culture duration and other culture conditions) should remain a priority within assisted reproduction technology.
  
  
  BACKGROUND
  None.
authors.affiliation: Centre for Reproductive Medicine, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, B-1090 Brussels, Belgium anick.devos@uzbrussel.be.
authors.forename: A
authors.initials: A
authors.lastname: De Vos
authors.affiliation: Centre for Reproductive Medicine, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, B-1090 Brussels, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Janssens
authors.affiliation: Centre for Reproductive Medicine, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, B-1090 Brussels, Belgium.
authors.forename: H
authors.initials: H
authors.lastname: Van de Velde
authors.affiliation: Centre for Outcomes Research and Laboratory for Experimental Surgery, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, B-1090 Brussels, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Haentjens
authors.affiliation: Centre for Medical Genetics, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, B-1090 Brussels, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Bonduelle
authors.affiliation: Centre for Reproductive Medicine, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, B-1090 Brussels, Belgium.
authors.forename: H
authors.initials: H
authors.lastname: Tournaye
authors.affiliation: Centre for Reproductive Medicine, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, B-1090 Brussels, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: Verheyen
mesh_terms: D001724:Birth Weight; D003470:Culture Media; D046149:Embryo Culture Techniques; D006801:Humans; D016014:Linear Models; D027724:Reproductive Techniques, Assisted; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D003470:Culture Media
keywords: IVF/ICSI; birthweight; embryo culture; human; perinatal outcome