Causes of Female Infertility

Women are born with about 1 million eggs in their ovaries and do not generate new eggs, unlike men, who produce sperm throughout their life.

From age 35, ovarian reserve of women starts to decline, and once they reach 40 poor quality eggs usually outnumber healthy eggs. Therefore, their chances of getting pregnant with their own eggs are significantly reduced.

The natural pregnancy rate for women under the age of 30 is approximately 20 to 30 percent per month. However, by the age of 40, the probability of conceiving decreases to 5 percent.

With that information in mind, the female infertility causes can be classified into:

Ovulatory factor

Any hormonal imbalance or ovarian disorder can cause ovulatory alterations, which are responsible for about 25 percent of infertility cases in women. Some of the main ovulatory disorders are:

Amenorrhea
Anovulation
Premature ovarian failure (POF)
Hyperprolactinemia
Hypothyroidism and hyperthyroidism
Poor egg quality
Obesity
Ovarian cysts
Ovarian egg reserve
Insulin resistance
Polycystic ovary syndrome (PCOS, which is the most frequent of all)

Tubal factor

About 25 percent of female infertility cases are related to tubal factors. Fallopian tubes play a critical role in the reproductive process, since fertilization takes place within them and are also the means through which the newly formed embryo is transported to the uterus for its implantation and development.

Any damage to the fallopian tubes can cause infertility by preventing gamete (eggs and sperm) transport and fusion. It also prevents the transfer of the fertilized egg from the ovary to the uterus, increasing the risk of an ectopic pregnancy.

Tubal disorders are frequently caused by:

Pelvic adhesions
Positive chlamydia
Hydrosalpinx
Recurrent cervical-vaginal infections
Tubal ligation

Uterine factor

Between 5 and 12 percent of infertility cases are due to uterine defects, which can interfere with a proper implantation of the embryo and prevent the normal pregnancy development.

Some of the major uterine disorders are:

Adenomyosis
Endometriosis
Mullerian malformations
Uterine fibroids
Uterine polyps
Uterine synechiae

Embryological factor

When a woman’s egg fertilized, 23 chromosomes of the mother and 23 chromosomes of the father join together to constitute 46 chromosomes that represent the genetic material of each cell in the resulting embryo.

Genetic alterations may be caused by problems in one or both genes or chromosomes of the embryo. In some cases, these genetic problems can cause infertility or recurrent miscarriages, as they affect the embryo’s ability to implant and develop inside the maternal uterus.

Major embryonic disorders are: