other physical disorders

A variety of other physical disorders including structural disorders can also affect women’s fertility. The problems mentioned in this section are unlikely to be discernable to the average woman. Structural problems in a woman’s reproductive organs can be caused by a multitude of factors, including endometriosis, infections, congenital defects, inflammations, traumas, tumours and sicknesses.

problems with the fallopian tubes
endometriosis
adhesions
cervical mucous disorders
the immune system
uterus (womb) disorders

problems with the fallopian tubes

The fallopian tubes play a crucial role in the female reproductive process, where they function by using their many fingers or fimbrae as the connecting path between the ovaries and the womb (uterus). In addition, they create a favourable environment for the sperm. Scarred or blocked fallopian tubes can prevent the egg (ovum) from reaching the womb and the sperm from reaching the ovum. Blockages in the fallopian tubes are mostly caused by infections resulting from sexually transmitted diseases (STDs); while scarring may occur as a result of pelvic surgery, pelvic inflammatory disease (PID) or endometriosis. If only one tube is blocked, it is still possible to become pregnant. However, a partially blocked fallopian tube can increase the chances of an ectopic pregnancy, because it can prevent the passage of the fertilised egg - the embryo - to the womb.

endometriosis

The lining of the womb (uterus) is called the endometrium or the uterine membrane. Endometriosis is a condition whereby endometrial tissue grows outside of the womb, for example in or on the ovaries, the fallopian tubes, the bladder or the kidneys. Although outside the womb, this tissue undergoes the same cyclical changes as the normal endometrium. However, it cannot be shed as the endometrium normally is via the vagina.

Endometriosis can therefore cause painful, heavy periods as well as pain during intercourse, although it can also be present without causing any symptoms. A mild case of endometriosis has a minimal effect upon fertility. In more severe cases, adhesions and scar tissue can develop, which undoubtedly have a negative impact on fertility. The most commonly accepted (but not proven) theory about the cause of endometriosis is that the menstrual blood flows up into the fallopian tubes instead of down through the vagina leading to the presence of endometrial tissue outside the womb.

Endometriosis can reduce the chance of pregnancy in a number of ways:

Tissue growth can occur on the fallopian tubes, the outside of the womb or the ovaries. This tissue can cause a blockage or deformation.
If endometriosis is present in the ovary itself, blood-filled cysts can form (so-called chocolate cysts). This may hinder the growth of the follicles.
The tissue can secrete substances that although will not necessarily exclude fertilisation may reduce its chance of occurring.
There is an unproven theory that an immune reaction (immuno-response) can occur. Cells released during an immune reaction (macrophages) due to the presence of endometrial tissue outside the womb can - according to this theory - destroy eggs, sperm or embryos.

adhesions

Adhesions and scar tissue are mostly caused by abdominal infections, although they can also result from endometriosis and surgery. Adhesion possibly plays a role in a quarter - 25% - of the cases of female infertility.

The most common abdominal infections are appendicitis and colitis. These can cause an infection in the abdominal cavity, which may affect, for example, the Fallopian tubes and lead to scar tissue and blockages. Scarred ovaries can also be caused by PID - a condition characterised by infections of the pelvic organs. When, as a result of scar tissue, the ovaries’ position changes, the fimbria (the finger-like protuberances at the end of the fallopian tubes) may struggle to collect the egg after ovulation. Ovaries affected by PCO sometimes have a thickened exterior or topping, which can prevent the ovum from being released. Abdominal surgery can also cause scar tissue and adhesion.

cervical mucous disorders

Normal cervical mucous is an essential prerequisite for successful fertilisation. Many women notice a change in the consistency of their cervical mucous during their menstrual cycle. Around ovulation (egg release), the cervical mucous is clear and thin easing the passage of the sperm into the womb. But outside of the fertile period, this mucous acts as a barrier and is tough and more acidic. Although it provides protection preventing infections entering the womb, the sperm cells cannot survive in an acidic environment.

Disorders of the cervical mucous impact fertility if:

The cervical mucous is too thick during ovulation, preventing sperm from swimming through it.
The cervical glands do not produce enough mucous.
The mucous is too acidic during ovulation, rendering the sperm cells unviable.

In some cases, the glands that produce the cervical secretions may be damaged by infection or surgical treatment, which could eventually lead to disturbances in the mucous. The use of some hormones (including the medicine clomiphene citrate) can also have a negative influence on the composition of the cervical mucous.

the immune system

Disorders of a woman’s immune system are sometimes also identified as a possible contributor to reduced fertility. There is however no firm evidence for this and it remains a theory. Under normal circumstances, sperm and embryos are the only two “foreign bodies” which are not attacked by the female immune system. The immune system regards the embryo as a part of the female’s body, whereby it is effectively placed into quarantine in the womb and protected from attack. According to an unsubstantiated theory, the immune system of some women functions abnormally and attacks the sperm or embryo as if it were an invading or foreign cell.

uterus (womb) disorders

Disorders in or around the uterus (womb) are unlikely to interfere with the process of fertilisation, but may prevent an embryo from implanting or thereafter bring about a miscarriage. Some women are incorrectly diagnosed as being infertile, that is unable to become pregnant, while the disorder actually lies within the uterus – after fertilisation.

Some examples of uterine disorders are:

Myoma - these are benign lumps that form on the walls of the uterus. They may be covered in tentacles (polyps). Polyps in the cavity of the uterus are particularly prone to preventing the implantation or healthy development of the embryo.
Adhesions - Adhesions of the interior of the uterus can occur after surgery on the uterus, cutterage or, more rarely, after an infection. The most serious of these is described as Asherman’s Syndrome.
Congenital deformities - A number of variations are known. The womb may for example have a double horn or partition. These deformities do not generally influence fertility, but increase the risk of premature births and breech presentations.
Presence in an abnormal place - The womb can slip into the vaginal canal (prolapsed).