Women's Reproductive Health
Hormones are key to reproductive health in all aspects of a woman’s sexual life. They regulate menstruation, fertility, menopause, and sex drive (libido). The main hormones affecting the menstrual cycle and fertility are produced by glands in the brain and by the ovaries.
A part of the brain called the hypothalamus produces GnRH (gonadotropin-releasing hormone). GnRH is a hormone that triggers the pituitary—a pea-sized gland just below the hypothalamus—to release two other hormones: follicle stimulating hormone (FSH) and luteinizing hormone (LH). FSH and LH in turn start the process of ovulation (egg release) in the ovaries.
During this process, the ovaries also produce estrogen and progesterone, both of which help prepare the uterus for pregnancy. If pregnancy doesn’t occur, menstruation, the shedding of the lining of the uterus, marks the end of the menstrual cycle. If any of the hormones involved in the menstrual cycle are out of balance, the result can be irregular or missed periods.
Diagnosis of a female reproductive health problem starts with a woman’s medical history, physical and pelvic exams, and blood tests to measure hormone levels. Depending on the initial findings, other tests may be needed to complete the diagnosis. This approach applies to a wide range of female reproductive health issues—amenorrhea (lack of periods), infertility, menopause--hyperlink, and hormone-related female sexual dysfunction.
Amenorrhea is the medical term for absence of menstrual periods. Amenorrhea is abnormal except before puberty, during pregnancy and early breastfeeding, and after menopause--hyperlink. Any woman who misses more than three periods in a year’s time should see a doctor to find the cause.
Causes of amenorrhea
Amenorrhea is called primary if a woman hasn’t started menstruating by age 16 years. Primary amenorrhea is usually due to genetic or reproductive organ problems that are present at birth but not noticed until puberty. Turner syndrome is one example.
Amenorrhea is called secondary if a woman who has had periods in the past loses her period for at least six months. Pregnancy is the most common cause of secondary amenorrhea. Another common cause is early menopause, also called primary ovarian insufficiency (POI) or premature ovarian failure (POF).
Hypothalamic amenorrhea occurs when the hypothalamus in the brain slows or stops releasing GnRH, the hormone that controls the menstrual cycle. Women typically affected are those with eating disorders or who are athletes, such as ballet dancers, figure skaters, and runners. What they have in common is
- low body weight
- a low percentage of body fat
- a very low calorie or fat intake
- emotional stress
- strenuous exercise that burns more calories than are taken in through food
- some medical conditions or illnesses
Amenorrhea can also be caused by benign tumors in the pituitary gland, obesity, polycystic ovary syndrome, and adrenal gland disorders. (The adrenals are two small glands located above each kidney that produce some sex hormones.) Polycystic ovary syndrome (PCOS) is a common reproductive problem that sometimes causes amenorrhea. However, most women with PCOS have irregular menstrual periods, not amenorrhea.
Treatment of amenorrhea varies depending on the cause. It could involve changes in lifestyle such as gaining or losing weight, exercising less intensely, or reducing stress, medication, surgery to correct abnormalities in reproductive organs, or a combination of approaches. Some women take birth control pills to regulate their periods. These medications, which combine estrogen and progesterone, maintain balanced levels of the hormones in the body.
Prolonged amenorrhea may increase the risk of bone loss, so taking calcium and vitamin D supplements is recommended. Women with hypothalamic amenorrhea also need to gain weight or correct other underlying problems to keep their bones strong.
Infertility is the inability of a sexually active couple, not using birth control, to get pregnant after one year of trying. About one quarter of female infertility is caused by a problem with ovulation. Normally, each month an egg matures within its own follicle (a sort of bubble) in the ovary and is released into the fallopian tube. This process of ovulation is the fertile time of the menstrual cycle.
Reasons for infertility
Lack of ovulation or infrequent ovulation: Absent or irregular ovulation is a common cause of infertility, and can be caused by
- polycystic ovary syndrome (PCOS)
- hypothalamic amenorrhea
- problems that cause the pituitary to release too much prolactin, a hormone that affects estrogen levels
- primary ovarian insufficiency
Age: There is a gradual decrease in egg quantity and quality beginning when a woman is in her mid 30s, or about 10 years before menopause.
Other hormone-related conditions: An overactive or underactive thyroid gland, diabetes, obesity, and, occasionally, Cushing’s syndrome (a disorder of the adrenal glands) can affect fertility.
Other causes of infertility include tubal blockages, endometriosis, and male factor infertility.
Treatment of infertility
Infertility due to ovulation problems is treated with fertility drugs. These drugs, in general, work like natural hormones, such as FSH and LH, to bring about ovulation. Some commonly used fertility drugs are:
- Clomiphene: this oral medication causes the pituitary gland to release more FSH and LH.
- Gonadotropin therapy: these injected medications contain either FSH or both FSH and LH. These drugs stimulate the ovaries to develop egg-containing follicles. Most women need FSH only, but women with hypothalamic amenorrhea need both LH and FSH.
- Human chorionic gonadotropin (hCG): used in combination with clomiphene and gonadotropin therapy, this drug, which is also given by injection, stimulates the follicle to release its egg (i.e., to ovulate).
- Bromocriptine and cabergoline: these oral medications are used to treat infertility caused by the body’s production of too much prolactin. Too much prolactin can cause amenorrhea.
Polycystic ovary syndrome (PCOS) and infertility
PCOS is a leading cause of infertility in women (for a detailed discussion, see our Polycystic Ovary Syndrome overview). Although not all women with PCOS have all these features, common signs and symptoms include
- irregular menstrual cycles excess hair growth on the face and body
- infertility (due primarily to lack of ovulation)
- overweight or obesity (especially at the waist)
On ultrasound, the ovaries appear to have a ring of small cysts. These are painless and do not become large cysts.
Normally, a woman’s ovaries and adrenals produce small amounts of male hormones (androgens), but women with PCOS have increased androgen levels. Higher levels of androgens lead to an imbalance in the hormones that regulate ovulation and normal egg development. Obesity, which is common in women with PCOS, contributes to infertility. Thus, weight loss, if needed, and treatment for PCOS with medications can restore ovulation.
Primary ovarian insufficiency (POI) and infertility
POI (previously known as premature ovarian failure (POF), or early menopause), occurs when the ovaries stop working normally before a woman turns age 40. When this happens, women don’t ovulate on a regular basis or produce normal amounts of estrogen. The most common signs of POI are irregular or missed periods, along with hot flashes. Other symptoms may include
- night sweats
- vaginal dryness
- difficulty concentrating
In most cases, the cause of POI is unknown. It is sometimes linked to genetic disorders such as Turner syndrome and Fragile X syndrome, conditions that are due to changes to the X chromosome. The risk of developing POI is greater in women with a family history of the disorder.
Although some women with POI become pregnant, the chance of success is very low. Research is ongoing to identify treatments for restoring fertility in women with POI. Hormone therapy may be used to relieve menopause symptoms (such as hot flashes, night sweats, vaginal dryness) or to prevent osteoporosis (brittle bones).
Menopause is the time in a woman’s life when her menstrual cycles end and she can no longer get pregnant naturally. As a woman nears age 50 or so, the ovaries are close to running out of eggs, estrogen levels begin to drop, and the first signs of menopause may appear. The menopausal transition takes an average of 4 to 5 years, and during that time hormone levels are likely to fluctuate widely. Periods may become irregular, but a woman may still be able to get pregnant. Once the ovaries have stopped producing eggs, however, fertility ends. After menopause, women may experience sexual dysfunction as a result of lower levels of hormones.
For a detailed discussion of symptoms, treatment options, and the pros and cons of treatment, see our menopause section.
Female sexual dysfunction: hormone-related causes
Female sexual dysfunction is defined as a lack of interest in or enjoyment of sexual activity that is distressing to a woman. It can result from a loss of sex drive (libido), an inability to become aroused or to reach an orgasm, or painful intercourse. A combination of many personal, interpersonal, and medical factors may contribute to sexual dysfunction.
Physical causes may include health issues like diabetes, heart disease, nerve disorders, or hormone problems. Estrogen results in increased blood flow to the genitals and vaginal lubrication during arousal, and, because of its impact on mood and sleep, indirectly affects sexual interest. With menopause or menopause-like conditions, estrogen levels drop significantly, leading to physical changes (such as thinning vaginal tissue, dryness), that can dampen a woman’s sex drive. Androgens (male hormones) are also believed, but not proven, to be important for libido in women.
A hormonal imbalance may or may not contribute to any one woman’s low sex drive. But if a woman does have a hormonal cause for sexual dysfunction, treatment might include hormone therapy. Vaginal forms of estrogen— a cream, tablet, or vaginal ring—can improve vaginal tone, elasticity, and lubrication. Estrogen applied directly to the vagina is more effective at a lower dose than estrogen in pill or skin patch form. Also, the small amount of estrogen in these products is believed to pose less risk for heart attack, stroke, and breast cancer than pill or patch hormone therapy, which affects the whole body.
Androgen therapy for female sexual dysfunction is an emerging area of research. Androgens are male hormones, such as testosterone. Women produce testosterone, although in much smaller amounts than men. Testosterone production drops gradually after about age 30, and blood levels are considerably lower in postmenopausal women. Surgically menopausal women (who have had their ovaries removed) have even lower testosterone levels than women who go through natural menopause and are thus more likely to experience sexual dysfunction. To date, however, the U.S. Food and Drug Administration (FDA) has not yet approved testosterone-containing medications for women with sexual dysfunction.
Loss of libido, called hypoactive sexual desire disorder (HSDD), describes low or absent sexual interest or desire that causes marked distress or relationship problems and is not caused by a medical condition or drug. Currently, there is no FDA-approved treatment for HSDD but several products are being studied. These a testosterone gel absorbed through the skin and DHEA vaginal suppositories. (DHEA, or dehydroepiandrosterone, is a hormone produced by the adrenal glands that is converted to testosterone and estrogen.) Although not approved in the U.S., a testosterone patch is available in other countries as a treatment for HSDD.
Kathryn Martin, MD
Massachusetts General Hospital
JoAnn Pinkerton, MD
University of Virginia
Last review: May 2013