Inability of a couple to conceive because of some abnormality/ cause in the female partner is called as female infertility. Isolated female factor is responsible for infertility in approximately one third of cases, while female factor plays a contributory role in another one third of infertile couples.
What are the causes of infertility among women?
The major causes of female infertility can be categorized as follows-
1. Age related infertility: Female fertility is greatly impacted by the age of the female partner. Women are generally most fertile in their 20’s and early 30’s and there is a gradual decline in their ability to conceive from the age of 35 years till 40 years. The decline in their fertility gets accelerated around the age of 40 years and very few natural pregnancies are seen above the age of 42- 43 years. The incidence of pregnancy related accidents such as miscarriages and that of chromosomal abnormalities like Down’s syndrome is also much higher in conceptions of women with advanced maternal age.
2. Ovulatory disorders like Poly Cystic Ovarian Syndrome (PCOS): Normal fertile women produce and ovulate a mature egg in their menstrual cycle for optimum fertility. This normal cycle gets disrupted in some women because of production of excessive amount of male hormones (androgens) from the ovaries, which can also lead to the appearance of multiple cyst like pattern in the ovaries- thus the name polycystic ovaries. Excessive male hormones disturb secretion of hormones like FSH and LH, which are essential for growth and maturation of eggs. This causes menstrual abnormality and irregular ovulation, which result in infertility. Excessive amount of androgens also cause appearance of acne and male pattern hair growth (called hirsutism) in women. Women with PCOS are also at an increased risk of developing other disorders like diabetes, cardiovascular disease and endometrial cancers.
3. Tubal disorders-Fallopian tubes play a very important role- both structurally and functionally- in normal reproductive process. The fallopian tubes constitute an essential passage in the woman’s body, for the sperms and eggs to meet and fertilize. The tubes are lined by very delicate hair (cilia) from inside, which help and push the egg and zygote towards the uterine cavity. The tubes can get damaged due to infections such as pelvic inflammatory diseases and tuberculosis or scarring resulting from trauma, surgery or diseases like endometriosis. Tubal factor, including blocked or damaged fallopian tubes, is estimated to be responsible for up to 20% cases of female factor infertility. The diagnosis of tubal patency can be made by following tests:
- Hysterosalpingography- This is the first line of investigation in assessment of tubal patency. A radio-opaque dye is injected into the uterus using a tube put into the uterus through vagina. Serial X rays are taken while injecting the dye in order to assess passage of the dye through the fallopian tubes. Free passage of the dye through the tubes and its spillage from the end of the tubes is the hallmark of a patent tube.
- Laparoscopy- Laparoscopy is the gold standard investigation for checking the patency of fallopian tubes. It is a minimally invasive surgical procedure in which a small telescope is inserted through a small incision under the navel and tubes are examined directly under vision. A radio-opaque dye is injected into the uterus using a tube put into the uterus through vagina, while the abdominal cavity is examined internally using the telescope. Spillage of the dye from the ends of the tubes indicates that the tubes are patent.
4. Fibroids: Fibroids are non-cancerous tumors of the uterine smooth muscle, which grow within the uterine walls. They are seen in 20- 40% women of reproductive age group. The impact of fibroids on fertility of a woman is based on the location and size of the fibroids. Fibroids present or growing on the outside of the uterus (into the abdominal cavity) have the least impact on woman’s fertility. On the other hand, fibroids growing within the uterine cavity (called as submucous fibroids) can interfere with attachment of the embryo to the uterine wall, and can thus cause infertility. Other symptoms associated with fibroids include severe painful cramps and excessive bleeding during menstruation (menorrhagia).
5. Endometriosis: Endometriosis is a condition in which the endometrial tissue that normally grows only inside the uterine cavity starts to grow at other sites away from the uterus. The growth of this tissue is dependent on the cyclical hormonal changes in a woman’s body just like growth of normally located endometrial tissue. However, while the endometrium is shed along with menstruation at the end of each cycle, the abnormally located tissue is not able to escape the body, and leads to the formation of blood filled cysts called endometrioma. This can also lead to formation of scar tissue affecting uterus, ovaries, tubes and adjacent organs like bowel. Women with endometriosis present with painful periods, painful intercourse, pain in lower abdomen and infertility. Infertility in women suffering from endometriosis results mainly due to the poor function of the fallopian tubes and lower ovarian reserve in such women.
6. Uterine causes: Uterus it is the final destination for the embryo, where it gets attached and develops into a fetus. A healthy uterus is essential for childbearing. Uterine abnormalities causing infertility can result from abnormal development of the uterus (conditions like unicornuate/ bicornuate/ septate uterus), infections in the uterus (like tuberculosis) and damage to the uterine lining due to prior curettage of uterine cavity. Damaged uterine lining can cause formation of adhesions inside the uterus (called as Asherman’s syndrome), which in turn can cause infertility.
7. Hormonal causes:
8. Unexplained Infertility: Despite of a comprehensive evaluation of the couple, a definite cause for infertility may not be identified in up to 10% cases, and these couples are referred to as having unexplained infertility.
What is primary ovarian insufficiency?
Primary ovarian insufficiency (POI) is a condition in which the ovaries stop functioning normally in women younger than 40 years of age. This condition was earlier known by names of “premature ovarian failure” and “premature menopause,” but these terms are misleading and are not actively used now.
Women with primary ovarian insufficiency do not always stop menstruating and their ovaries do not always completely shut down, but they have diminished ovarian reserve. However, these women tend to menstruate irregularly and may eventually become menopausal at rather younger age. This reduces the chances of pregnancy in these women. Not only this, these women generally produce poor quality of eggs and consequently poor quality of embryos and are also at a higher risk of chromosomal abnormalities and miscarriage. These women generally respond poorly to fertility treatment and are also predisposed to early onset osteoporosis and cardiovascular complications.