Introduction to Infertility

A woman’s age is the main factor affecting a couple’s chances of achieving a successful pregnancy. A woman’s fertility peaks between the ages of 20 and 30 years. From 30 to 35 years of age, female fertility starts to slowly decline. Once a woman turns 35, her fertility begins to drop more rapidly. Over the age of 40, women have significantly lower chances for conception each month.

Age of WomanPregnancy Rate*
20-2486 percent
25-2978 percent
30-3463 percent
35-3952 percent

*Range Pregnancy Rate (within 12 months of trying)

The definition of infertility is based on age:

  • Age 34 and younger: regular intercourse for one year without birth control not resulting in pregnancy;
  • Age 35 and older: regular intercourse for six months without birth control not resulting in pregnancy.

Birth control includes birth control pills, diaphragm, condoms, or the rhythm method. Infertility is not the same as being sterile. Sterility is when you cannot get pregnant and the problem cannot be corrected.

Fifteen to 30 percent of otherwise healthy adults have fertility issues. With help, many fertility issues can be treated.

Deciding When to Go for an Infertility Evaluation

This largely depends on your age. Although infertility is defined as not becoming pregnant after a year of trying, some couples should be evaluated before one year of trying has passed. If you are less than 35 years old, it is reasonable to try for one year before getting a medical evaluation. However, as a woman ages, her chances of getting pregnant decrease, and an earlier evaluation is recommended. The standard of care is to evaluate based on the woman’s age:

Age of WomanWhen to Seek an Evaluation
Less than 35 years oldAfter one year of trying
35-40 years oldAfter six months of trying
Over 40 years oldBegin evaluation immediately**

**While trying to become pregnant

Causes of Infertility

There are many different causes of infertility, and often there are several infertility causes in one couple. These include:

Male factor infertility

In about 25-40 percent of couples, a problem with the sperm is the cause of the infertility. The problem may be the number of sperm, the shape of the sperm, or their ability to move effectively.


In 25-30 percent of couples, there are problems with the release of the woman's egg, or ovulation. This may be the result of an abnormality in the woman's ovary (such as polycystic ovary syndrome), or other hormonal causes. These defects are treated by giving medications to stimulate ovulation.

Tubal defect

In 20-30 percent of couples, infertility is caused by an abnormality of the Fallopian tubes, the tubes that connect the ovaries to the uterus. Tubal defects can be caused by scarring from previous surgery, infection, or a previous tubal ligation ("tying of the tubes").


This is a disorder in which pieces of the lining of the uterus attach to pelvic organs, including the Fallopian tubes, the ovaries, and sometimes even the intestines. This can cause pain, scarring, and changes in the ability of the eggs to fertilize and create a pregnancy. This is the cause of infertility in 5-10 percent of couples.

Unexplained infertility

There is no obvious cause of infertility in about 10-20 percent of couples. Fertility treatments also are successful in these cases, however.

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