Cause of Infertility

Think the woman is always to blame when a couple is infertile? Think again. About one-third of infertility cases are due to male problems, one-third are due to female problems, and the rest are due to a combination of male/female factors or to unknown causes. Infertility can be linked to a number of causes, including age, medical conditions, and lifestyle choices.

An Introduction to the Causes of Infertility

There are many different reasons why a couple might be dealing with infertility. It is a myth that infertility is always a "woman's problem." About one-third of infertility cases are due to problems with the man (male factors) and one-third are due to problems with the woman (female factors). The final third of infertility cases are due to a combination of male and female factors or to unknown causes.

Possible Causes of Infertility

Some of the possible causes of infertility in females include:
  • Age
  • Lifestyle choices
  • Low ovarian reserve
  • Premature ovarian failure
  • Medical conditions, such as:
    • Uterine fibroids
    • Endometriosis
    • Pelvic inflammatory disease
    • Polycystic ovarian syndrome
    • Luteal phase defect.
Some possible causes of infertility in males include:
  • Age
  • Lifestyle choices
  • Environmental toxins
  • Medical conditions
  • Medications.

More Detail on Infertility Causes

Below are more detailed reasons why a person may be having trouble conceiving:
One common cause of infertility is age. Women today are often delaying having children until later in life, when they are in their 30s and 40s. Many factors add to this trend: birth control is easy to obtain and use, more women are in the work force, women are marrying at an older age, the divorce rate remains high, and married couples are delaying pregnancy until they are more financially secure.
However, the older you are, the more difficult it is to become pregnant. Women generally have some decrease in fertility starting in their early 30s. While many women in their 30s and 40s have no problems getting pregnant, fertility especially declines after age 35.
As a woman ages, there are normal changes that occur in her ovaries and eggs. All women are born with over a million eggs in their ovaries (all the eggs that they will ever have) but only have about 300,000 left by puberty. Of these, only about 300 eggs will be ovulated during the reproductive years. Even though menstrual cycles continue to be regular in a woman during her 30s and 40s, the eggs that ovulate each month are of poorer quality than those from her 20s. It is harder to get pregnant when the eggs are poorer in quality.
Ovarian reserve is the number and quality of eggs in your ovaries and how well the ovarian follicles respond to hormones in your body. As you approach menopause, your ovaries don't respond as well to your hormones, and in time, they may not release an egg each month.
Low Ovarian Reserve
A reduced ovarian reserve is natural as a woman ages, but young women might have reduced ovarian reserves due to:
  • Smoking
  • A prior surgery on their ovaries
  • Family history of early menopause.
Also, as a woman and her eggs age, if she becomes pregnant, there is a greater chance of genetic problems, such as having a baby with Down syndrome. Embryos formed from eggs in older women are also less likely to fully develop, a main reason for miscarriage (early pregnancy loss).
Premature Ovarian Failure (POF)/Ovarian Insufficiency
Healthcare providers use the term premature ovarian failure, or POF, to describe a stop in normal functioning of the ovaries in a woman under the age of 40 (women's ovary function naturally begins to decline at age 40). In this cause of infertility, the ovaries stop making eggs and stop making certain hormones.
An estimated 250,000 women under age 40 have POF in the United States.
Last reviewed by: Arthur Schoenstadt, MD
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