EVANGELOS MAKRAKIS - Causes of Infertility

Infertility

Infertility
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There is a great variety of factors that may affect a couple’s fertility. The presence of one of these factors does not exclude the existence of some other one within this same couple, while one of these factors may have different impact among different couples. For this reason, we must consider, investigate and treat infertility as a couple’s problem and not isolate it to the male or to the female partner.

The factors leading to infertility may be roughly classified as follows:

Ι) Female infertility factors: The female factor may concern the fallopian tubes, the ovaries, the endometrium, the cervix, or the vagina

Tubal factor infertility: The tubal factor is responsible for a 25-30% of infertility cases. The encounter between ovum and spermatozoa and the fertilization process take place in the fallopian tube; therefore, conditions that affect the anatomy or function of the fallopian tubes may lead to infertility. These conditions are: 1) Severe infections of the female reproductive system like acute salpingitis or pelvic inflammatory disease may cause tubal obstruction, damage of the normal structure of tubal walls, hydrosalpinx (dilated tubes filled with fluid), or adhesions within the pelvis that could strangle and obstruct the fallopian tubes. 2) Endometriosis may lead to infertility by means of several processes such as tubal motility and micro-structure disorders or creation of adhesions within the pelvis. 3) Former surgical operations in the woman’s abdomen may also produce adhesions with consequent problems in the fallopian tubes.
Ovarian factor infertility: In a 15-20% of infertility cases it is demonstrated that the problem lies in the function of ovaries. The conditions falling under this category are practically the following: 1) Conditions of anovulation, where there is no release of the oocyte which would normally happen in the middle of each regular menstrual cycle. Some indicative causes of anovulation are: polycystic ovarian syndrome, early failure of ovarian function, extreme stress, extreme physical training, obesity, or on the contrary an extremely low weight and poor nutrition, brain tumors or disorders, liver and kidney diseases. 2) Conditions of hormonal deficiency after ovulation that lead to lack of the ideal conditions for the fertilized ovum’s implantation in the uterus. This disorder is named luteal phase deficiency.
Uterine factor infertility: In a 5-10% of infertility cases the problem is located in the woman’s uterus. This case comprises fibroids (and more specifically those projecting into the uterine cavity), endometrial adhesions observed in women having undergone numerous curettages, severe or recurrent uterine infections, and finally cervical mucus disorders such as deficiency, altered composition, or presence of antibodies which immobilize spermatozoa.
Endometriosis: This is a peculiar disease of the female with endometrium-consisted spots appearing beyond their natural position (which is the uterine cavity). There is a general estimation that a 15-25% of infertile women suffer from endometriosis, while a 30-20% of those women with endometriosis demonstrate infertility. The processes by which endometriosis may cause infertility have been the subject of intensive study. Apart from the abovementioned impact on the fallopian tubes, other possible processes are: destruction of sperm after its entry to the female reproductive system, ovarian function disorders and particularly the inhibition of ovulation (a condition called luteinized unruptured follicle), and a local disorder of the immunological system leading to the release of conflicting substances against reproduction.

ΙΙ) Male factor infertility

In contrast with what was believed in the past, in a 30-50% of couples facing infertility problems the cause is located in the male partner by means of various sperm disorders. A natural and adequate sperm is prerequisite for the achievement of fertilization with many parameters being evaluated for this purpose. First of all, the number of spermatozoa contained in the sperm should be adequate. If this number is lower than normal, then we have oligospermia; if there are no spermatozoa, the condition is called azoospermia. The motility of the spermatozoa is also important as those should be able to move with their own forces within the female reproductive system and travel up to the fallopian tubes. Thus, a decreased motility of spermatozoa called asthenospermia has a negative impact on the sperm’s fertilization capacity. Finally, the morphology should be normal for the highest possible percentage of spermatozoa. In addition to the above sperm features, there are other factors of significant importance such as the volume of sperm, the presence of inflammatory cells in the sperm, as well as the presence of antisperm antibodies. The latter adhere to the sperm cells thus affecting both their motility and their ability to fertilize the ovum.

There is a wide variety of conditions that may lead to sperm disorders. Such conditions are: Testicle inflammations (the most known one is mumps) as well as severe prostates inflammations; injuries, lesions or torsion of the testicles causing their destruction; a congenital or acquired obstruction of the tubules through which the spermatozoa pass through before ejaculation; varicocele; the intake of various toxic drugs, the impact of radiation on the testicles, as well excess alcohol consuming; various congenital disorders in the male’s genes or chromosomes; rare tumors or lesions in the central neural system; finally, a temporary sperm disorder may as well appear in men living at high altitudes, with poor nutritional intake, practicing extreme physical activity, or wearing tight underwear that boost temperature in the area of testicles.

III) In a 10-20% of infertile couples, the complete diagnostic investigation of both man and woman is proved to be totally normal. In those cases the infertility factors are considered as unknown or unclear; these are the unexplained infertility cases.