Smoking lowers chance of fatherhood

If you're going to plunk down thousands to try to have a baby by in vitro fertilisation, it would be a good idea to quit smoking first.

A new study has found that women whose partners smoke cigarettes are much less likely to conceive using in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) than women with non-smoking partners.

Confirming suspicions
"This study supports what we have felt in the infertility world for a long time - that there is an association between male infertility and smoking," says Dr Andrew McCullough, director of the sexual health, male infertility and microsurgery programs at New York University Medical Centre. McCullough was not involved in the new research.

To perform in vitro fertilisation, doctors must give a woman high doses of hormones to make her ovulate. Then, the woman's eggs are harvested and placed in a petri dish with the man's sperm. If all goes well, the sperm will fertilise the eggs to create embryos. The embryos are then implanted back into the woman.

ICSI is similar, except the egg and the sperm aren't just left in the dish. Scientists manually fertilise the eggs by taking a single sperm and injecting it into the egg. Success rates for the procedure vary and depend on factors such as maternal age, how many eggs are retrieved and the health of the eggs and sperm.

High percentage difference
Researchers from the Institute for Reproductive Medicine at the University of Münster, Germany, recruited 301 couples scheduled to receive assisted reproduction - 153 for ICSI and 148 for IVF. Some went through more than one treatment cycle. The researchers studied a total of 415 treatment cycles.

One hundred and thirty nine men and 77 women were smokers.

For couples receiving ICSI, 38 percent of the women with non-smoking partners became pregnant compared to 22 percent of the women with smoking partners. For the IVF group, only 18 percent of the women with smokers became pregnant versus 32 percent of the women with non-smokers.

Results of the study were presented today the annual conference of the European Society of Human Reproduction and Embryology in Vienna, Austria.

Focussing on lifestyle's effects
Michael Stahler, director of the In Vitro Fertilisation Laboratories at William Beaumont Hospital in Royal Oak, USA., says this study is "an important beginning."

A lot of previous research has focused on the woman's role in conception, but researchers should also be studying how the male lifestyle can affect fertility, he says.

Recommendations
McCullough says that while the study's findings make sense, he's concerned that it did not factor in the women's ages and whether they were smokers. He says the sample size simply wasn't big enough for the researchers to break down the data by these factors.

McCullough and Stahler both recommend that men avoid illicit drugs, tobacco and excessive drinking, especially when trying to conceive. Also, both point out that the use of steroids can have a serious impact on fertility.

McCullough also cautions against repeated hot whirlpool baths. And Stahler adds that excessive caffeine use probably hampers sperm function. - (HealthScout)

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