There are many known causes of infertility. Some are more absolute than others. For example, if a woman has blocked fallopian tubes, or a man has a very low sperm count or motility, then we know the cause of the couples infertility problem (or at least one of the causes). However, there are other fertility issues that are difficult to characterize as "the problem" - but we know that often they are at least factors contributing to the infertility.

This page is not meant to be a complete discussion of this issue. However, here are some general comments about our knowledge of the relationship between female tobacco smoking and reproduction:

• Over 20 published studies in the medical literature have detailed the adverse effects of tobacco smoking on fertility
• Tobacco smoke contains several hundred substances, many of which are toxic
• A study done in mice showed that nicotine had disruptive effects on egg maturation, ovulation rates, and fertilization rates. The study also showed more chromosomal abnormalities in the eggs exposed to nicotine.
• Ovarian reserve and egg quantity and quality are reduced in women who smoke
• Smokers have lower numbers of follicles when stimulated for in vitro fertilization
• Smokers have lower numbers of eggs retrieved with in vitro fertilization
• Smokers have lower rates of fertilization of the eggs with in vitro fertilization
• Smokers have increased rates of miscarriage with in vitro fertilization pregnancies
• One study showed that the chance for an IVF pregnancy was 2.7 times higher for women who have never smoked as compared to women that do (or have previously). The same study showed that if the woman smoked for over 5 years, the risk was increased to 4.8
• There is also some evidence that male smoking decreases success rates with IVF. It is not known whether this effect would be caused directly by the sperm, or whether it represents a negative effect on the egg and embryo quality through passive exposure (second hand exposure).

If you smoke - quit. If you are having trouble getting pregnant or particularly if you are planning to go through in vitro fertilization - quit even sooner. Fertility can improve after quitting, and IVF success rates are higher in women that used to smoke than in women that smoked during the ovarian stimulation, egg retrieval, embryo transfer time frame.