Smoking Is Bad When You Are Pregnant But Its OK While You Are Trying Isn't It?

Smoking is a very bad idea when you are pregnant because the chemicals in tobacco smoke narrow the blood vessels in the placenta making it more difficult for the growing baby to get the nourishment it needs. Babies born to mothers who smoke are often underweight at birth and can have other problems.

There is now new evidence that smoking before pregnancy, whilst trying to conceive is also a very bad idea. A new study has just shown that heavy smoking may reduce female fertility by directly affecting the uterus – it makes it less receptive to a fertilised egg and reduces the chances the embryo will implant.

The finding, from a team of fertility experts in Portugal and Spain, comes as a result of comparing the pregnancy rates between non-heavy smokers and heavy smokers, all of whom received donated oocytes. Two groups of women getting IVF treatment were compared; 741 non-heavy smokers (under 10 cigarettes a day) and 44 heavy smokers (over 10 a day). None of the women's partners were smokers and none of the oocyte donors were heavy smokers. The two groups of recipients were comparable and the number of embryos transferred in each cycle (between one and three) was also comparable between the groups.

Results shown that the non-heavy smokers had a significantly higher pregnancy rate, with over half becoming pregnant (52.2%), compared with just over a third (34.1%) of the heavy smokers.