Late planning (advanced age)
The trend today is for women to complete their education and establish their careers before they think of settling down and starting a family. However, for a woman over the age of 35, conceiving becomes a problem. Infertility increases with age. Fertility peaks for both sexes in their mid-twenties and then appears to decline steadily in women over thirty and men over forty. Tubal infections, fibroid tumors and endometriosis are more common in older women and are a common cause for infertility.

Excessive drinking, smoking, drug use
Research has shown that the excessive consumption of alcohol or the use of illicit drugs like marijuana, cocaine, heroin and crack, by a potential father prior to pregnancy or by women who have amused their body, can be the cause of infertility. Illicit drugs can also reduce the sperm count, damage the sperm, reduce testosterone levels, and change testicular functioning. (These are generally ejaculated with the sperm.) Heavy drinking can affect a woman’s menstrual cycle as well. Note however, that as long as drinking, smoking and drug use have been curtailed before getting pregnant, prior use seems to pose almost no risk to the baby.

Ovulation/menstruation problems
Ovulation is a pre-requisite for getting pregnant. In women with regular menstrual cycles of 28-35 days, ovulation takes place once every cycle. However, many women have erratic menstrual cycles (often getting periods 3-4 times a year or even less). This means that they have fewer chances of getting pregnant not only because they have fewer possible fertile periods, but also because they may not be ovulating in every cycle. (Note that ovulation does not necessarily take place in every menstrual cycle).

Low sperm count (for males)>
The normal sperm count ranges from 20 million to 100 million sperm per cubic centimeter. Counts below 20 million may be a cause for difficulty in conception. Factors such as fatigue, excessive alcohol, smoking or other drug abuse, prostate gland infection, poor diet, or occupational exposure to chemicals can cause a small, temporary decrease in the sperm count. Varicocele is a condition when there are varicose veins on the scrotum. This is another cause for infertility and can only be corrected through surgery.

Polycystic ovaries
Cysts are formed when the follicle fails to rupture at the time of ovulation and begins to grow instead. This condition occurs due to hormonal imbalance and is marked by absent or infrequent menstruation. Women having this condition have a chronic tendency to have their periods at intervals ranging from every six weeks to six months. Conception becomes difficult due to irregular ovulation.

Intercourse pattern
Very often, you may simply be mistiming your intercourse. In order for you to get pregnant, it is essential for you to have sex during your fertile days. It could also be possible that you may be trying too often in a particular cycle, and thereby causing a reduction in sperm count.