Sex may increase chances of IVF success

Having sex at or around the time of IVF (in vitro fertilisation) embryo implantation may increase the chances of pregnancy, according to new research carried out at Adelaide University. Dr Kelton Tremellen and his team studied over a thousand embryos transferred to women undergoing IVF in Spain and Australia. They found that the implantation rate was 50 per cent higher in women who had intercourse around the time of the transfer than in those who abstained. Dr Tremellen says the increase in the success rate resulted in an increase in the number of twins and triplets. The findings were published in the latest issue of Human Reproduction.

However, UK fertility expert Simon Fishel said he would not recommend sex immediately after IVF, because of the tiny risk of dislodging the embryo. And Gab Kovacs, of the Monash Clinic in Melbourne said the study is unlikely to change couples' behaviour. 'In our experience, women are reluctant to have intercourse after embryo transfer because of pain and bleeding' he told New Scientist last week.

But Dr Tremellen thinks that intercourse may not actually be necessary to achieve the effect: 'If we can determine what it is in semen that is having this beneficial effect then hopefully we'll be able to transfer fewer embryos each cycle, and achieve good pregnancy rates' he explained. He thinks that semen may increase the chances of implantation because it helps the mother's immune system 'ignore' the growing embryo.