title: Fetal exencephaly arising as a result of preimplantation exposure to ammonium chloride.
abstract: OBJECTIVE
  To investigate the effect of preimplantation exposure to 0.6 mM ammonium chloride on both preimplantation and postimplantation development of (F1 x F1) strain mouse embryos.
  
  
  METHODS
  Two-cell stage mouse embryos were randomly allocated to culture in either M16 medium or M16 added with 0.6 mM ammonium chloride for 2 days before being transferred to 2.5 day pseudopregnant recipients. Embryo morphology was assessed after 1 and 2 days of culture. The recipient females were sacrificed on day 15.5 of gestation. The number of implantation sites, fetuses, moles and any gross abnormalities found were noted.
  
  
  RESULTS
  There was no significant difference in the number of embryos reaching morula stage after two days of culture between the two groups (chi2=0.86, P>0.05). Implantation and pregnancy loss rates between the two groups were within comparable ranges. Crown-rump length was significantly higher in the group of embryos exposed to ammonium chloride (t=2.46, P<0.05). There was one gross abnormality, exencephaly, detected in the experimental group (4.35% per fetus obtained).
  
  
  CONCLUSIONS
  Besides the abnormal increase in fetal size, preimplantation exposure to ammonium chloride also resulted in gross abnormality, exencephaly. If such effects occurred in the course of human in vitro fertilization, it could be devastating. Further study in this aspect is, therefore, clinically very important in preventing unwanted abnormalities that could arise from human in vitro fertilization.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Khon Kaen University, Thailand.
authors.forename: S
authors.initials: S
authors.lastname: Sinawat
mesh_terms: D000643:Ammonium Chloride / Q000009:adverse effects*; D000818:Animals; D003470:Culture Media / Q000009:adverse effects*; D047108:Embryonic Development; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009436:Neural Tube Defects / Q000139:chemically induced*; D011247:Pregnancy; D011897:Random Allocation
chemical_list: D003470:Culture Media; D000643:Ammonium Chloride