Passive smoking can be as damaging as smoking to women taking fertility treatment. Smoking can affect a woman's fertility and damage sperm but researchers McMaster University in Hamilton, Canada found that exposure to second-hand smoke can affect the success rates of treatments such as in-vitro fertilisation (IVF). In a study that compared the outcomes of fertility treatment, it was found that smokers and women who lived with smokers had 20 percent pregnancy rate per embryo transfer, compared to 48 percent for non-smokers. The findings warrant a warning to women to reduce or, if possible, prevent exposure to cigarette smoking, especially if they are trying to conceive. There was no difference in the quality of the embryos from the three groups of women but they found a vast variation in the number of embryos that successfully implanted in the womb. When it came to implantation rates it was found that while non-smokers achieved a 25 percent implantation rate, both smokers and side-stream smokers managed only around 12 percent. Side-stream smoke is emitted from the smouldering end of the cigarette and contains the most toxic constituents. Passive smoking includes side-stream smoking and smoke exhaled by the woman's partner. Smokers in the study smoked a mean 11 cigarettes a day. The researchers do not understand why there is such a difference in implanting and maintaining a pregnancy in the smoking groups, despite the good quality and appearance of the embryos. They are planning a further study to try to answer the question.
Human Reproduction,
May 2005