What causes infertility in women?
Causes of infertility in women
The ability for a woman to become pregnant depends on both a healthy male and female reproductive system. About 30% of infertility is due to male problems relating to sperm quality. Another 50% of infertility is caused by female problems relating to ovulation or fallopian tube disorders. In about 30% of couples, the cause of infertility is unknown.
For women, around 40% of female infertility is caused by ovulation problems. Fallopian tube disorders account for 30% of infertility problems in women. Endometriosis accounts for 15% of female infertility.Problems relating to the cervix or uterus are least common.
Irregular ovulation cycles (8 or fewer periods per year) or anovulation (inability to release eggs) is the most common cause of female infertility. The release of an egg is a complicated hormonal process that begins with the hypothalamus and pituitary gland in the brain sending signals to the ovary to release an ovum (egg or oocyte).
The ovum then must travel through the fallopian tubes where it is fertilized by a sperm. Structural problems or blockages in the fallopian tubes are the second most common cause of infertility in women.
Causes of ovulation dysfunction include:
Hypogonadism is an abnormal function of the hormonal balance that causes abnormally low production of reproductive hormones. The lack of estrogen results in irregular or no ovulation in women. The disease may originate in the hypothalamus, pituitary, or ovaries.
There are many causes of hypogonadism including:
- Excessive exercise or low body mass index
- Pituitary disorder
- Tumors of the nervous system
- Premature ovarian failure (POF)
Polycystic ovary syndrome (PCOS) is one of the major causes of infertility. The ovaries are often enlarged and contain cysts. Symptoms of PCOS include menstrual irregularity, excessive or high levels of reproductive hormones, polycystic ovaries, acne, and obesity.
Causes of fallopian tube damage or blockage include:
Pelvic inflammatory disease (PID) – an untreated Chlamydia or gonorrhea infection can damage the fallopian tubes and block the passage of an egg.
Previous tubal, cervical or pelvic surgery can scar the tubes or damage the cervix.
Endometriosis – up to 40% of infertile women have endometriosis. Endometriosis is the buildup of abnormal endometrial tissue that, in severe cases, can damage the fallopian tubes. Endometriosis may also disrupt the hormonal regulation that controls ovulation.
Uterine fibroids – fibroids are abnormal tissue growths in the uterus that can prevent the fertilized egg from implanting in the womb.