Home Forums Blogs Articles Photos Videos Contact FAQ

Infertility - Causes

Infertility - Causes: Encyclopedia II - Infertility - Causes

Infertility - Primary vs. secondary. According to the American Society for Reproductive Medicine, infertility affects about 6.1 million people in the U.S., equivalent to ten percent of the reproductive age population. Female infertility accounts for one third of infertility cases, male infertility for another third, combined male and female infertility for another 15%, and the remainder of cases are "unexplained"2. A Robertsonian translocation in either partner may cause recurr ...

Infertility: Encyclopedia II - Infertility - Causes

Infertility - Causes

Infertility - Primary vs. secondary

According to the American Society for Reproductive Medicine, infertility affects about 6.1 million people in the U.S., equivalent to ten percent of the reproductive age population. Female infertility accounts for one third of infertility cases, male infertility for another third, combined male and female infertility for another 15%, and the remainder of cases are "unexplained"².

A Robertsonian translocation in either partner may cause recurrent abortions or complete infertility.

"Secondary infertility" is difficulty conceiving after already having conceived and carried a normal pregnancy. Apart from various medical conditions (e.g. hormonal), this may come as a result of age and stress felt to provide a sibling for their first child. Technically, secondary infertility is not present if there has been a change of partners.

Infertility - Female infertility

Factors relating to female infertility are:

General factors
- Diabetes mellitus, thyroid disorders, adrenal disease
- Significant liver, kidney disease
- Psychological factors
Hypothalamic-pituitary factors:
- Kallmann syndrome
- Hypothalamic dysfunction
- Hyperprolactinemia
- Hypopituitarism
Ovarian factors
- Polycystic ovary syndrome
- Anovulation
- Diminished ovarian reserve
- Luteal dysfunction
- Premature menopause
- Gonadal dysgenesis (Turner syndrome)
- Ovarian neoplasm
Tubal/peritoneal factors
- Endometriosis
- Pelvic adhesions
- Pelvic inflammatory disease (PID, usually due to chlamydia)
- Tubal occlusion
Uterine factors
- Uterine malformations
- Uterine fibroids (leiomyoma)
- Asherman's Syndrome
Cervical factors
- Cervical stenosis
- Antisperm antibodies
- Insufficent cervical mucus (for the travel and survival of sperm)
Vaginal factors
- Vaginismus
- Vaginal obstruction
Genetic factors
- Various intersexed conditions, such as androgen insensitivity syndrome

Infertility - Male infertility

Factors relating to male infertility include³:

Pretesticular causes
- Endocrine problems, i.e. diabetes mellitus, thyroid disorders
- Hypothalamic disorders, i.e. Kallmann syndrome
- Hyperprolactinemia
- Hypopituitarism
- Hypogonadism due to various causes
- Psychological factors
- Drugs, alcohol
Testicular factors
- Genetic causes, e.g. Klinefelter syndrome
- Neoplasm, e.g. seminoma
- Idiopathic failure
- Cryptorchidism
- Varicocele
- Trauma
- Hydrocele
- Mumps
Posttesticular causes
- Vas deferens obstruction
- Infection, e.g. prostatitis
- Retrograde ejaculation
- Hypospadias
- Impotence
Genetic causes

Some causes of male infertility can be determined by analysis of the ejaculate, which contains the sperm. The analysis includes counting the number of sperm and measuring their motility under a microscope:

Producing few sperm, oligospermia, or no sperm, azoospermia.
A sample of sperm that is normal in number but shows poor motility, or asthenozoospermia.

Infertility - Combined infertility

In some cases, both the man and woman may be infertile or sub-fertile, and the couple's infertility arises from the combination of these conditions. In other cases, the cause is suspected to be immunological or genetic; it may be that each partner is independently fertile but the couple cannot conceive together without assistance.

Infertility - Unexplained infertility

In about 15% of cases the infertility investigation will show no abnormalities. In these cases abnormalities are likely to be present but not detected by current methods. Possible problems could be that the egg is not released at the optimum time for fertilization, that it may not enter the fallopian tube, sperm may not be able to reach the egg, fertilization may fail to occur, transport of the zygote may be disturbed, or implantation fails. It is increasingly recognized that egg quality is of critical importance and women of advanced maternal age have eggs of reduced capacity for normal and successful fertilization.