It is well known that smoking and pregnancy doesn't mix. Just why is smoking so bad for fertility, conception and pregnancy?

Many, many studies have been done on the effects of smoking on conception, pregnancy and on young infants. One shows that women who smoked took up to a year longer to conceive, compared to non smoking women.

Women who smoke during pregnancy cause many issues for the infants - including higher mortality rates, low birth rates and respiratory problems.

Many of these risks are associated with passive smoke as well. So if the woman who wishes to become pregnant lives in or works in an environment that is extremely smoky, she may have the same issues.

In men, smoking has been linked to issues of low sperm count and low sperm viability.

Ex smokers, and those who leave a smoke-rich environment, revert back to normal chances of conception after about a year.