New research by scientists at Queen's University has revealed that Viagra affects fertilization and early embryo development in mice.

Research Fellow Dr David Glenn, from the Department of Obstetrics and Gynaecology, presented the findings at the European Society of Human Reproduction and Embryology in Berlin on Wednesday.

In the study, female mice were mated with males who had been given a single oral dose of Viagra or a control substance. Numbers of embryos and their stages of development were compared and results showed that female mice who were mated with males dosed with Viagra produced 33% fewer fertilized eggs.

By day four of development there were 40% fewer embryos in mice who had been mated with males dosed with Viagra. Moreover, there was a trend for embryos in the Viagra group to develop more slowly, although this did not reach statistical significance.

Wednesday's findings follow on from previous work by the group, presented by Dr Glenn at the British Fertility Society, in Cheltenham, in April. Viagra, when added to human semen, was found to affect sperm motility and prematurely induce the acrosome reaction – a reaction which normally occurs when a sperm comes into contact with an egg. When this reaction is induced prematurely, the sperm is rendered incapable of fertilization.

(MB)