Disclaimer note: While both men and women can be infertile, this article focuses on female infertility, it’s most common causes, and treatments. For information relating to male infertility click here.
Overview of Female Infertility
Female infertility is defined as the inability to conceive or carry a pregnancy to term after 12 months of unprotected intercourse or 6 months if the woman is over 35 years old. Typically, female infertility is linked to anatomical malfunctions or complications of the reproductive system but can also be caused by behavioral and environmental factors as well. Novel findings in the scientific community as well as technological advancements have made it possible to treat infertility depending on its cause and severity. Also, infertility not only affects a woman’s ability to get pregnant but may affect her relationships as well.
According to Stanford University, infertility affects about 10% of women in the United States 1. Globally, that percentage is difficult to determine due to male and female factors that complicate any estimate 2. With that in mind, the World Health Organization found that one in every four couples in developing countries had been affected by infertility. Furthermore, infertility in women is ranked the 5th highest serious global disability among populations under the age of 60 2. The difficulty to find accurate statistics regarding infertility rates lies in the fact that there are numerous definitions, causes, and views of infertility. Many women do not know they are infertile until they begin trying to conceive. Even then, not becoming pregnant may be a result of other factors such as stress. Therefore, it is important to understand different definitions of infertility and the complications that cause it.
- Clinical Definition of Infertility: A disease of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse. 2
- As a Disability: Infertility generates an impairment of function, and thus access to health care falls under the United Nations Convention on the Rights of Persons with Disability preamble. 2
- Primary Infertility: When a woman is unable to bear a child, either due to the inability to become pregnant or the inability to carry a pregnancy to live birth. 2
- Secondary Infertility: When a woman is unable to bear a child, either due to the inability to become pregnant or the inability to carry a pregnancy to live birth following either a previous pregnancy or a previous ability to carry a pregnancy to live birth. 2
What Causes Female Infertility?
There are many different reasons why a female may be or become infertile. Age is a major cause of infertility because women are born with a finite number of eggs. Therefore, as a woman gets older and the number and quality of her eggs decrease, she will have a harder time getting pregnant. Otherwise, primary infertility is typically due to anatomical complications or malfunctions that inhibit the ability to become pregnant. Secondary infertility is usually linked to damages of the reproductive system from invasive surgeries and infections. Just because these are the most common causes of primary and secondary infertility does not mean that invasive surgeries cannot cause primary infertility or vice versa, anatomical complications can cause secondary infertility.
Infertility is most commonly linked to ovulatory disorders, which account for 30% of cases. Ovulatory disorders may stem from hormonal problems, scarred ovaries, premature menopause, and follicle problems amongst others. Hormonal problems usually cause anovulation, which is key in understanding infertility. If ovulation cannot occur due to these hormonal complications then it is impossible to become pregnant. Ovulation depends on a complex interaction of the Follicle Stimulating Hormone (FSH) and the Luteinizing Hormone (LH). FSH stimulates the ovarian follicle, which causes the egg to grow and simultaneously produces estrogen in the follicle. The rise of estrogen alerts the pituitary gland to halt FSH production and to produce more LH. Increased LH production causes the follicle to burst and release the egg from the ovary into the fallopian tube where it can be fertilized. If there is discrepancy in this chemical interaction, ovulation will be disrupted. Most commonly, these hormonal problems are linked to a malfunction of the hypothalamus, which is the part of the brain responsible for sending signals to the pituitary gland or a malfunction of the pituitary gland itself, which produces and secretes FSH and LH. Physical damage to the ovaries may also result in failed ovulation 1. For instance, if a woman has multiple invasive surgeries for ovarian cysts she is at a much higher risk of damaging the ovaries and loosing the ability to ovulate.
Poorly functioning fallopian tubes or tubal disease affects approximately 25% of infertile women and varies widely, ranging from mild adhesions to complete tubal blockage 1. Tubal disease is typically linked to infection, abdominal disease, previous invasive surgeries, ectopic pregnancies, or congenital defects. Sexually transmitted infections can cause inflammation of the fallopian tubes and damage or scar them. Abdominal disease, such as appendicitis, causes inflammation of the abdominal cavity that can lead to tube blockage 1. Invasive surgeries may also lead to infertility in that they may cause tubal damage that restricts the egg from traveling through them. Ectopic pregnancy occurs when the fertilized egg implants into the fallopian tube itself rather than in the uterus. This may not only result in infertility but is potentially life threatening as well. Congenital defects refer to women who are born with tubal abnormalities of which cause problems with egg transportation and fertilization.
Endometriosis affects about 10% of infertile women 1. Approximately 30-40% of patients with the complication are infertile, which is 2 to 3 times the rate of infertility in the general population 1. Endometriosis is caused by abnormal growth of the endometrial tissue, which is the inner lining of the uterus. If the tissue spreads and grows outside of the uterus then infertility may occur depending on the severity of the abnormal growth. While the exact causes of endometriosis are unclear, retrograde menstruation is most probable. This causes the endometrial discharge to travel backwards up into the oviducts and becomes stuck in the pelvic cavity or irregular places outside the uterus.
There are also behavioral and environmental factors that can inhibit a woman’s ability to get pregnant. For instance, women who are significantly overweight or underweight may have difficulty becoming pregnant 1. Therefore, diet and exercise is critical in maintaining a healthy reproductive system. Other behavioral factors include smoking, the use of alcohol and drugs, and even involvement in stressful jobs or situations. While these may or may not directly cause infertility, these behavioral factors can combine with anatomical malfunctions and decrease a woman’s ability to become pregnant.
Environmental factors that contribute to infertility consist of frequent exposure to various toxins or chemicals in the workplace or the surrounding environment 1. These substances are termed reproductive toxins because they have the ability to cause mutations, birth defects, miscarriages, sterility, and infertility. Despite the fact that considerable controversy exists regarding the impacts of toxins on fertility, four chemicals are now regulated based on cases that found the toxins to be the main cause of the inability to get pregnant 1. These regulated reproductive toxins are lead, radiation, ethylene oxide, and dibromochloropropane (DBCP).
Infertility can be treated in numerous ways depending on the cause and severity of it. Advancements in modern technology and medicine have evolved to provide some women who were infertile with the ability to become pregnant. Anatomical complications can be corrected by both surgery and medicine. In some cases, simple changes in lifestyle can create the ability to become pregnant, given that infertility is due to the behavioral factors listed above. If the woman is indefinitely infertile and treatment is not possible then a female can seek a surrogacy agreement.
Ovulatory disorders can be treated using drugs such as Clomiphene® and Menogan/ Repronex®, which have been noted to have a 70% success rate 1. Tubal disease is commonly treated by surgeries using lasers and microsurgery technology with success rates (defined as the number of women who become pregnant within one year of surgery) as high as 30% overall, while certain procedures can be up to 65% successful 1. As for endometriosis, treatment relies on the severity of the condition and the symptoms. Anti-inflammatory pain relievers such as ibuprofen can help manage the pain, while birth control pills or other hormonal medications can control the growth of the endometrial tissue, reduce inflammation, and overall reduce endometriosis’ impact on fertility. Surgery can also correct endometrial complications depending on the tissue’s growth and location. For more information regarding assisted reproductive technology (ART) click here.
1. University, Stanford. "Infertility Treatment." Stanford Edu. Stanford Education, 2012. Web. 20 Oct. 2015.
2. World Health Organization. "Infertility." WHO.com. World Health Organization, 2015. Web. 22 Oct. 2015.
Last Update: 3 March 2016.