Alcohol

This is another habit that should be stopped if you are trying to conceive. There are mixed messages as to whether drinking a little bit during pregnancy is safe. I say steer clear totally because you stand to gain a lot more and save yourself the worry and blame if anything happens to your child.

Excessive alcohol consumption during pregnancy can cause a lot of problems especially in the early stages of pregnancy, which is when the baby's organs and limbs develop. If a woman consumes a lot of alcohol at this stage the alcohol could get into the babies bloodstream and cause a defect known as foetal Alcohol Syndrome. This defect can affect the baby's facial features, cause behavioural problems and can restrict his growth and development.

Other problems associated with alcohol intake during pregnancy include

Miscarriages

Low birth weight

Heart problems

Ladies anytime you think of alcohol while trying to conceive think of all the pain and suffering you may cause your child. I don't think it's worth it

For guys, excessive alcohol can 

Reduce sperm quality

Reduce sperm quantity

Reduce libido

And can eventually cause impotence.

Bottom line, men avoid excessive alcohol intake especially while trying to conceive.

Ladies, avoid alcohol altogether while trying to conceive.

If you need help stopping you can contact your local hospital or medical Center for a list of agencies that can assist you.


Recreational Drugs

Couples trying to conceive are also advised to avoid using recreational drugs such as marijuana, cocaine, heroin etc. These drugs affect sperm health and productivity in men and cause ovulatory and menstrual irregularities in women.

References
http://www.nhs.uk/chq/Pages/2270.aspx?CategoryID=54#close
http://www.alcohol-focus-scotland.org.uk/alcohol-pregnancy
http://www.drinkaware.co.uk/check-the-facts/health-effects-of-alcohol/fertility-and-pregnancy/is-alcohol-harming-your-fertility
http://www.fertilityfriends.co.uk/forum/index.php?topic=136220.0