Infertility is defined as inability of a couple to conceive naturally after one year of regular unprotected sexual intercourse. It remains a major clinical and social problem, affecting perhaps one couple in six. Evaluation usually starts after 12 months; however it may be indicated earlier. The most common causes of infertility are: male factor such as sperm abnormalities, female factor such as ovulation dysfunction and tubal pathology, combined male and female factors and unexplained infertility.

Infertility can be broken down into primary and secondary infertility.

Primary infertility is defined as the absence of a live birth for women who desire a child and have been in a union for at least 12 months, during which they have not used any contraceptives. The World Health Organisation (WHO) also adds that 'women whose pregnancy spontaneously miscarries, or whose pregnancy results in a still born child, without ever having had a live birth would present with primarily infertility'.

Secondary infertility is defined as the absence of a live birth for women who desire a child and have been in a union for at least 12 months since their last live birth, during which they did not use any contraceptives.

Thus the distinguishing feature is whether or not the couple have ever had a pregnancy which led to a live birth.

Cause of female infertility

The following causes of infertility may only be found in females. For a woman to conceive, certain things have to happen: vaginal intercourse must take place around the time when an egg is released from her ovary; the system that produces eggs has to be working at optimum levels; and her hormones must be balanced.

For women, problems with fertilisation arise mainly from either structural problems in the Fallopian tube or uterus or problems releasing eggs. Infertility may be caused by blockage of the fallopian tube due to malformations, infections such as chlamydia and/or scar tissue. For example, endometriosis (a state in which pieces of the tissue alike to the lining of the uterus (endometrium) grow in other parts of the body) can cause infertility with the growth of endometrial tissue in the Fallopian tubes and/or around the ovaries. Endometriosis is usually more common in women in their mid-twenties and older, especially when postponed childbirth has taken place.

Another major cause of infertility in women may be the inability to ovulate. Malformation of the eggs themselves may complicate conception. For example, polycystic ovarian syndrome is when the eggs only partially developed within the ovary and there is an excess of male hormones. Some women are infertile because their ovaries do not mature and release eggs. In this case synthetic FSH (follicle-stimulating hormone) by injection or Clomid (Clomiphene citrate) via a pill can be given to stimulate follicles to mature in the ovaries.

Other factors that can affect a woman's chances of conceiving include being overweight or underweight, or her age as female fertility declines after the age of 30.
Sometimes it can be a combination of factors, and sometimes a clear cause is never established.

Causes of male infertility

The main cause of male infertility is low semen quality. In men who have the necessary reproductive organs to procreate, infertility can be caused by low sperm count due to endocrine problems, drugs, radiation, or infection. There may be testicular malformations, hormone imbalance, or blockage of the man's duct system. Although many of these can be treated through surgery or hormonal substitutions, some may be indefinite. Infertility associated with viable, but immotile sperm may be caused by primary ciliary dyskinesia. The sperm must provide the zygote with DNA, centrioles, and activation factor for the embryo to develop. A defect in any of these sperm structures may result in infertility that will not be detected by semen analysis.

Infertility is considered also a public problem. It does not affect the couples' life only, but it also affects the healthcare services and social environment. The feelings experienced by the infertile couples include depression, grief, guilt, shame, and inadequacy with social isolation.

Infertility may be associated with several diseases include: 

Erectile dysfunction

As was mentioned above, feelings of stress, depression, guilt, or anxiety in infertile men can cause psychogenic impotence, which heightens the feelings of inadequacy that already accompany infertility. The psychological stress of infertility has been shown to affect sperm parameters in significant and demonstrable ways that may further contribute to difficulties with erectile potency; emotional reactions to the infertility may alter or even undermine a previous consolidation of a sense of self as sexually adequate. Infertility weighs on many males' minds; this creates mental instability, which often results in impotence. Even with an erection problem, a man may still have sexual desire and be able to have an orgasm and to ejaculate. Thus, it is important to keep in mind that it can be helped if the roots of stress are detected. Talking to a partner about worries, changing life-style and/or maintaining work-life balance can decrease the likelihood of erectile dysfunction.

Undescended testes

Many men who were born with undescended testes have reduced fertility, even after orchiopexy in infancy. The fertility reduction after orchiopexy for bilateral cryptorchidism is more marked, about 38%, or 6 times that of the general population.
At least one contributing mechanism for reduced spermatogenesis in cryptorchid testes is temperature. The temperature of testes in the scrotum is at least a couple of degrees cooler than in the abdomen and the temperature rising may damage fertility. Some circumstantial evidence suggests tight underwear and other practices that rise testicular temperature for prolonged periods can be associated with lower sperm counts. Nevertheless, research in recent decades suggests that the issue of fertility is more complex than a simple matter of temperature. It seems likely that subtle or transient hormone deficiencies or other factors that lead to lack of descent also impair the development of spermatogenic tissue.

Retrograde ejaculation

Males with retrograde ejaculation are not irreversibly infertile because sperms are presented in urine and it is possible to isolate them with the help of assisted reproduction techniques. The procedure includes adjustment of the osmolarity of the patient's urine by drinking water. The small amount of antegrade-produced ejaculate is collected in a plastic beaker, while the retrograde fraction of the ejaculate needs to be urinated immediately into a jar with culture medium containing human serum albumin to dilute the urine. Finally, the urine/medium mixture has to be centrifuged, resuspended and filtrated on the glass wool column where sperms are separated. When the sperm is isolate than it could be injected directly into the egg (which is maintained from woman by transvaginal oocyte retrieval). The following procedure is IVF-ICSI.

Fallopian tube blockage

Tubal factor infertility accounts for nearly one-quarter of all cases of infertility. The fallopian tubes may be abnormal in structure or function. Structural disorders can block the fallopian tubes. They include tubal scarring or blockage most commonly from pelvic infections, prior abdominal surgeries and endometriosis. Practically, many gynecologists are reluctant when reporting on diagnostic laparoscopy. Some perform a single puncture intraumbilical procedure that neglects an auxillary portal for proper grasping of the adnexa and thorough evaluation of the ovarian fossa. Tubal pathologies may be responsible for primary and secondary infertility. The evaluation of the fallopian tube is necessary to determine the management plan of infertility. A number of diagnostic tests are being used in clinical practice to assess tubal patency as part of the work-up for subfertility.

Pelvic Inflammatory Disease (PID)

PID can cause scarring and damage which can affect fertility. If both or one of the fallopian tubes are blocked due to scars and adhesions, then the sperm will not reach egg and egg cannot make way to the uterus. This prevents fertilization and also pregnancy. If only one fallopian tube in blocked, there is yet a possibility that a woman can get pregnant, since the other tube can release an egg and let a sperm swim through. Two blocked fallopian tubes, however, are not a good sign for women who wish to naturally become pregnant. Untreated PID can result in long term complications including ectopic pregnancy and infertility.

Vaginismus

Due to the discomfort when attempting penetration for some women entry of the penis may be impossible, thus, women suffering from vaginismus might be also struggling with infertility. Also, they may fail to consummate their marriage and inability to conceive can lead to even greater pain and depression. Since the woman cannot have sexual intercourse with partner, she may perceive herself as a failure and feel even more pressured and anxious. It is important not to blame yourself for this condition and it is highly recommended to seek a professional advice. With professional advice and help women can cure vaginismus and could even conceive.

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Sources

Infertility ―sourced from Wikipedia licensed under CC BY-SA 3.0
Pelvic inflammatory disease ―sourced from Fertilitypedia licensed under CC BY-SA 4.0
Fallopian tube blockage ―sourced from Fertilitypedia licensed under CC BY-SA 4.0
UNDESCENDED TESTES ―sourced from Fertilitypedia.org licensed under CC BY- SA 4.0
RETROGRADE EJACULATION ―sourced from Fertilitypedia.org licensed under CC BY- SA 4.0
ERECTILE DYSFUNCTION ―sourced from Fertilitypedia licensed under CC BY-SA 4.0
Vaginismus ―sourced from Fertilitypedia licensed under CC BY-SA 4.0
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