IVF treatment less effective in women living with a smoker

May 26 2005

According to Canadian study passive smoking is apparently as damaging to a woman’s chances of having successful fertility treatment as being a smoker.

The study suggests that women having IVF treatment and living with a smoker who has ten or more cigarettes a day, reduce their chances of becoming pregnant by half.

Although exposure to smoke has long been suspected to affect a woman’s ability to become pregnant, this latest study now indicates that even sidestream smoke given off by a smouldering cigarette is just as damaging.

A research team, from McMaster University and Hamilton Health Sciences in Ontario, studied 225 women having fertility treatment, and they compared the quality of embryos and the implantation and pregnancy rates of non-smokers, smokers or women living with a partner who smoked regularly.

The team found that there was no difference in embryo quality between the three groups, but they did find a remarkable difference in implantation and pregnancy rates between non-smokers and the other two groups.

The effects of passive smoking were so clear and so damaging that Michael Neal, a member of the McMaster team, said they were now warning all patients about the potential hazards to fertility.

Neal says they found that embryo quality and fertilisation rates were similar in the three groups, but there was a significant difference in the pregnancy rates per embryo transfer, with the non-smokers achieving around 48 per cent, the smokers around 19 per cent and the sidestream smokers 20 per cent.

The researchers now plan to examine why there is no difference in the appearance and development of embryos before they are implanted in the three groups, but a large decrease in the ability of embryos from sidestream smokers and smokers to implant or maintain a pregnancy. Mr Neal said that it was possible that cigarette smoke damaged the egg, but the lethal results were not apparent until later in the embryo’s development.

He says the study is unique in looking at the female, who is just as vulnerable, if not more vulnerable, to environmental toxicants such as cigarette smoke.

The findings are published in the journal Human Reproduction.