Infertility at a glance

  • Infertility, as defined by the American Society for Reproductive Medicine (ASRM) is the inability to achieve pregnancy after one year of unprotected intercourse.
  • After one year of failed attempts, an infertility evaluation is advisable; women 35 years or older may want to seek an evaluation sooner.
  • Infertility can be caused by recurrent pregnancy loss (miscarriage), ovulation issues, male factor infertility, problems with the fallopian tubes or uterus, endometriosis, and age.

Definition of infertility

Infertility, as defined by the American Society for Reproductive Medicine (ASRM) is the inability to achieve pregnancy after one year of unprotected intercourse. This definition also supposes that there are no obvious problems such as absence or infrequent menstrual cycles, which suggests poor ovulation. By these standards, one in seven couples has trouble conceiving.

Younger couples, particularly where the woman is younger than 30 years old, are less likely to suffer from infertility. After one year of failed attempts, an infertility evaluation is advisable to discover the cause. Women 35 years or older may want to seek an evaluation sooner in order to have more time for treatment.

Other candidates for early infertility evaluation are women who have irregular menstrual cycles or known fertility issues – such as tubal blockage, abnormal ovulation, endometriosis, or uterine or cervical disorders – or a partner who likely has male-factor infertility.

Causes of infertility at a glance

Infertility in women

Common causes of female infertility include:

Infertility in Women: In-Depth

Infertility in men

Common causes of male infertility include:

Infertility in Men: In-Depth

Primary causes of infertility

Miscarriages: recurrent pregnancy loss

Pregnancy loss, or miscarriage, is a common occurrence in up to 30 percent of all pregnancies, and some losses happen as part of a natural process and pass without the woman’s notice. However, a woman who experiences two or three obvious miscarriages is generally considered to be suffering from recurrent miscarriages.

Consulting with a fertility specialist may be advisable to explore the cause of miscarriage and possible treatment options. The decision to seek help may be based on age, number of miscarriages that have occurred, if a family history of pregnancy loss is present, or if there is any known risk associated with the miscarriages.

Ovulation factor

One of the most common causes of infertility in women is a problem with ovulation, or lack of ovulation. The American Society for Reproductive Medicine reports that approximately 25 percent of all infertility problems are ovulation related. During the ovulation process, an egg suitable for fertilization is developed, and the woman may experience ovulation symptoms, such as increased cervical mucous production and ovulation pain.

Regular menstrual cycles do not eliminate the possibility of an ovulation problem. Pregnancy is the only solid proof that ovulation has occurred.

Male factor

Male factor infertility is found in approximately 40 percent of infertile couples. In these cases, the male partner is either the sole source of infertility, or part of the problem.

About 10 percent of infertile men have hormonal problems that lead to low or insufficient sperm counts. Another 10 percent have sufficient sperm counts, but have an obstruction along the genital tract that inhibits the sperm from leaving the testes through the ejaculate. The majority of male infertility, however, is caused by sperm abnormalities of uncertain etiology.

Male infertility is evaluated through testing and analyzing a semen sample produced by masturbation after two or three days of abstinence. The number, shape, and movement of the sperm are evaluated and abnormality in any one of these parameters may suggest a source for the infertility.

Tubal factor

According to the ASRM, about 35 percent of all infertility problems are caused by tubal factors – disorders affecting the fragile fallopian tubes. For the reproductive system to work, the fallopian tubes must be open, allowing sperm to fertilize the egg in the tube and then helping to transport the embryo to the uterus.

Several tests, such as a hysterosalpingogram or a laparoscopy, can determine if the fallopian tubes are blocked. Often, a blockage discovered during the procedure can be corrected by surgery at the same time. However, if the problem is severe or irreversible damage exists, then in vitro fertilization becomes the best option to achieve a successful pregnancy.

Age factor

Women are born with a certain number of eggs in their ovaries, and many are lost with each menstrual cycle. This relentless loss occurs even if the woman is pregnant, on hormonal contraception, or undergoing any suppression of ovulation. Because of this, age is a big factor in a woman’s fertility. Even before the menopause occurs, most women progressively lose their most fertile eggs.

Studies show that women younger than 30 years old have a very good chance of achieving a pregnancy but then start to have subtle reductions in their fertility. At age 37-38 this decrease becomes somewhat more pronounced and over the age of forty the fertility curve drops even more steeply.

Unless fertility problems have already been diagnosed, women younger than 30 generally should not be concerned about infertility until pregnancy attempts are unsuccessful after a full year.

Uterine factor

Uterine abnormalities can also be a cause of infertility, but are less common than tubal or ovulatory factors. Scarring, polyps (benign glandular tumors inside the uterus), and uterine fibroids (benign tumors of the uterine muscle) are all examples of uterine abnormalities. Uterine fibroids can cause infertility when they are located in or close to the uterine cavity or when they are so large that they distort the uterine cavity itself.

Cervical factor

The cervix is the muscle that controls the lower opening of the uterus. Sperm enter the uterus through the cervix on their way to the fallopian tubes, and the fully developed baby passes through the cervix during birth. Cervical conditions are rarely the cause of infertility, but issues that could affect fertility include freezing or laser treatments, surgery, or if the woman’s mother took DES (diethylstilbestrol) during the time the woman was in utero.


Endometriosis is a cellular disorder that causes the tissue that normally lines the uterus to grow outside of the uterus. Not only does this sometimes cause abdominal discomfort or severe pain, the tissue may also attach itself to organs or other structures within the pelvis and cause scarring. If the tissue attaches to the ovaries, it may need to be removed.

According to the American Society for Reproductive Medicine (ASRM), 35 percent of women with no other diagnosed infertility problems have endometriosis, and it is a common factor in women with infertility.

Unexplained infertility

Approximately 5 percent to 10 percent of couples unable to conceive are diagnosed with unexplained infertility, according to the ASRM. This is defined by the presence of infertility despite all infertility tests coming back normal.

The longer the period of infertility, the less likely a couple is to conceive without reproductive assistance. The chance for unaided success drops to less than 10 percent after a couple has been infertile for five years. Women with unexplained infertility who undergo fertility treatments like intrauterine insemination (IUI – also called artificial insemination) and in vitro fertilization (IVF) tend to have high success rates.