The harmful effects of smoking or being overweight were strongest among those women who had no obvious cause for not conceiving, according to the research, published today (Thursday 7 April) in Europe's leading reproductive medicine journal Human Reproduction.
Lead researcher Dr Bea Lintsen, from Radboud University Nijmegen Medical Centre, said: "The positive news from our results, however, is that they suggest that couples in particular, women with unexplained subfertility may be able to improve the success of IVF treatment by quitting smoking and losing weight."
The research was a collaboration by doctors from twelve centres in the Netherlands who drew on data from a proportion of patients involved in the nation-wide OMEGA study, which was begun in 1995 to examine late effects of hormone stimulation. The team investigated the success rate of the first cycle of treatment in 8,457 women, analysing information on reproduction and lifestyle factors, combined with medical records of IVF treatment from 1983 to 1995. ICSI cycles were not evaluated as the treatment was not common during that period.
They divided the cause of subfertility into four categories fallopian tube problems, male subfertility, unexplained fertility, and other causes (mainly women with polycystic ovarian syndrome or endometriosis) and analysed first cycle treatment results for the first three causes. Of the total, 1,828 of the first IVF treatment cycles were for unexplained subfertility.
The overall live birth rate per cycle was 15.2%. It was highest at 17.8% in couples with unexplained subfertility. Women with tubal problems had a 14.6% rate and the lowest success rate was f
Contact: Emma Mason
European Society for Human Reproduction and Embryology