ULTRASOUND COVERS AND SONOGRAPHIC GELS ARE EMBRYO-TOXIC AND COULD BE REPLACED BY NONTOXIC POLYETHYLENE BAGS AND PARAFFIN OIL

The objective of this study was to test the hypothesis that ultrasound covers and sonographic gels, used during vaginal ultrasound, are toxi c for mouse embryonic development irt vitro, A prospective randomized design was used on pronucleate ova of F1 hybrid CBA x C57Bl female mic e. The mice were superovulated with pregnant mare's serum gonadotrophi n and human chorionic gonadotrophin and mated with CBA x C57Bl males. The pronucleate ova were randomly divided between culture media with t he addition of commercially available ultrasound covers and sonographi c gels in different concentrations. As controls and potential alternat ives, plastic polyethylene bags and paraffin oil were tested simultane ously. Embryo-toxicity was assessed by documenting cleavage capacity, blastocyst formation and embryo degeneration in vitro. Exposure of cul ture medium to the ultrasound covers and sonographic gels tested resul ted in a severely reduced cleavage capacity, a high incidence of embry o degeneration and absent or impaired blastocyst formation. This toxic effect could be reduced by high dilutions in vitro. In contrast, plas tic polyethylene bags and paraffin oil had no influence on in-vitro de velopment of mouse ova, We conclude that commercially available ultras ound latex covers and sonographic gels are toxic for mouse embryos and can potentially influence embryonic development during infertility tr eatment. It is safer to perform vaginal ultrasonic measurements using non-toxic paraffin oil (as contact fluid) and plastic polyethylene bag s (as ultrasonic cover).