Women smokers who try for a baby may take up to two months longer to conceive than non-smokers, doctors say.

Researchers have, for the first time, measured the effect of the habit on a woman's chances of becoming pregnant.

A study looked at the success rates of 569 women aged around 29 who were trying to have a baby, including smokers, ex-smokers and non-smokers. Its findings show that those who continued to smoke took, on average, almost two months longer to conceive than women who gave up smoking during that period.

However, quitting helps immediately. Within a year of giving up, ex- smokers took no longer to become pregnant than women who had never smoked. Chief researcher Dr. Marcus Munafo, from the Imperial Cancer Research Fund's General Practice Research Group, said women were encouraged not to smoke during pregnancy because of the harm it causes the unborn baby. But smokers should now consider quitting even earlier - as soon as they decide they want to try for a baby. He said: "There is a lot of evidence about the risks of smoking durring pregnancy such as higher mortality, the increased risk of the baby developing serious respiratory infection ,a nd lower birth weights.

'But many women may not be aware that quitting also greatly improves their chances of getting pregnant in the first place. The study clearly shows a link between smoking and fertility problems.'Published in the Journal of Biosocial Science, the study suggests heavy smokers are affected to a greater degree.

But Mr. Munafo stressed that smoking made conception harder for all women. It is not clear how smoking damages women's fertility, but it may affect the release of an egg before fertilisation or the quality of the eggs.

Dr. Munafo said: 'When trying to conceive, many women often change their lifestyle by cutting down their alcohol intake, taking vitamins and minerals and eating a healthier diet. this study shows that stopping smoking should be a part of this pre-conception routine and women should quit as soon as they are thinking about having a baby. The message from this research is that if you want to get pregnant, you will not only improve your chances by quitting, you will also be doing something to protect the health of your child in the long term.'Other research has found that if a non-smoking woman is exposed to passive smoking, her chances of conceiving within a year are reduced by 14 per cent.

Source: Daily Mail, Wednesday, 31 Oct 2001