For a man and a woman who are having frequent intercourse without using any birth control, the average amount of time that it takes to conceive is six months. Most couples are able to achieve a pregnancy within one year if they have intercourse frequently (twice per week or more often). Between 10% and 15% of couples will continue to have difficulty conceiving after one year of trying. When pregnancy is this slow to occur, the man and woman are diagnosed as infertile.
Infertility can be caused by health problems in the man, the woman or both partners. In some infertile couples, no cause can be found to explain the problem. In approximately 20% of couples, more than one cause of the infertility is found. The cause of infertility occurs about as often in men as in women.
Normal aging reduces a woman's ability to become pregnant. Ovulation, the process of forming and releasing an egg, becomes slower and less effective. Aging begins to reduce fertility as early as age 30, and pregnancy rates are very low after age 44, even when fertility medications are used. Even though fertility is less reliable for women of older ages, approximately 20% of women in the United States have their first child at or after age 35.
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