Causes of Female Infertility
Female infertility at a glance
- A woman’s fertility and pregnancy potential is determined by the ovarian reserve (the quality and quantity of eggs remaining in a woman’s ovaries). A quarter of infertility cases are caused by female ovulation problems.
- Uterine irregularity such as uterine fibroids can affect fertility when located in or close to the uterine cavity, or when they are so large that they distorted the shape of the uterine cavity.
- If the fallopian tubes are blocked or damaged, the fertilization process cannot occur or the embryo cannot continue the journey into the uterus, causing infertility.
- Hormonal problems can sometimes cause or foster infertility, and the levels of several key hormones may be tested during an infertility evaluation.
A quarter of infertility cases are caused by ovulation problems, according to the American Society for Reproductive Medicine (ASRM). Ovulation is a pivotal reproductive process when the egg is developed for fertilization, so testing the ovaries for ovulation is a good starting place for a fertility evaluation, particularly when the woman has absent or infrequent menstrual cycles.
A woman’s fertility and pregnancy potential is determined by the ovarian reserve, which is a measure of the quality and quantity of eggs remaining in a woman’s ovaries. Barring any other problems in the reproductive tract, an assessment of ovarian reserve can reveal if the amount of eggs in the ovaries are affecting fertility. Testing generally involves several blood tests (FSH, estradiol and anti-müllerian hormone) as well as an ultrasound of the ovaries on the second or third day of the menstrual cycle.
During a basic infertility evaluation, an assessment of the uterus should be performed to check for irregularities in the uterus. An example of a uterine irregularity that affects fertility is uterine fibroids, which affect fertility when located in or close to the uterine cavity, or when they are so large that they distorted the shape of the uterine cavity.
Because the uterus (like the fallopian tubes) is made of soft tissue, a normal X-ray cannot show irregularities, so special imaging tests must be performed. These can reveal other causes of infertility within the uterus, such as scarring or benign glandular tumors called polyps.
The fallopian tubes
In order for sperm to fertilize an egg, the ovaries must release the egg into the fallopian tubes. If the tubes are blocked or damaged, the fertilization process cannot occur or the embryo cannot continue the journey into the uterus. This type of infertility problem accounts for 35 percent of infertility cases, according to the ASRM.
Hormonal problems can sometimes cause or foster infertility, and the levels of several key hormones may be tested during an infertility evaluation. Of these, progesterone is the most critical and usually the first hormone tested. Progesterone levels generally peak one week after ovulation, and can be measured through blood tests to detect the amount of progesterone present in the blood stream.
Follicle stimulating hormone (FSH) helps control the menstrual cycle and egg production. Estradiol increases during the menstrual cycle and is a marker of ovarian function and quality of eggs. These hormones are evaluated early in the menstrual cycle to evaluate ovarian reserve, along with anti-müllerian hormone and an ultrasound of the ovaries. Estradiol is also frequently evaluated during treatment cycles to assess growth and quality of the developing egg.
Luteinizing hormone (LH) is another critical hormone that is frequently tested, usually in a urine sample just before ovulation occurs. LH stimulates the ovaries to release an egg so urinary measurement of this hormone is helpful to time intercourse or intrauterine insemination