Although getting pregnant may seem like the easiest thing in the world, it is actually not so for many people. There are several reasons for this, and any one or more of the following may be applicable.
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 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 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.
Many women are born with their uteruses facing backward (retroverted) instead of forward. This condition can be diagnosed either by your gynecologist, or through an ultrasound. One simple way to compensate for this problem of a retroverted uterus is for the woman to lie on her stomach after intercourse. (Women with regular uteruses who are planning to get pregnant are asked to lie on their backs and lift their legs from their hips after sex in order to improve the chances of fertilization). If retroverted uterus is the only problem, then in most cases the woman will conceive. However, if she still does not get pregnant, then the doctor may advise surgery.
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.
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.