Causes of Infertility
Infertility is the inability to achieve pregnancy after one year of frequent unprotected intercourse. 1 in 6 couples will have a problem conceiving.
About 25% of couples trying to conceive unsuccessfully have unexplained infertility meaning that all the basic investigations of the female and male partner are normal. Unexplained infertility could be due to factors such as problem of egg fertilisation by the sperm, subtle problem of the function of the Fallopian tubes, genetic or chromosomal problem affecting the eggs and/or sperm or problem affecting implantation of the fertilised egg.
- Ovulation problem
Meaning that eggs are not released from the ovaries each cycle. By far the commonest reason is polycystic ovaries. Low ovarian reserve is another reason when the ovaries become almost depleted of eggs. Testing for ovulation and ovarian reserve are two basic crucial tests for the female partner.
- Scarring or blockage of the Fallopian tubes
- Blockage of the Fallopian tubes can be caused by a previous genital infection. The commonest infection causing scarring and damage of the Fallopian tubes is Chlamydia.
- Pelvic endometriosis which is a condition where the lining of the womb is found outside the womb causing inflammation and scar tissue formation which can damage the Fallopian tubes.
- Previous pelvic surgery for ectopic pregnancy, removal of ovarian cysts, ruptured appendix or bowel resection for any reason.
The presence of endometriosis is as such could be a cause of infertility even when the Fallopian tubes are not blocked. The exact reason is not entirely clear. It is believed to be related to chemical substances released by the endometriosis that make the environment unfavourable for egg fertilisation and embryo implantation. Laparoscopy is required to diagnose and treat endometriosis at the same time.
They are benign overgrowth of the muscles of the womb. They are present in 20-25% of women. They can be multiple and of different size and location within the womb. Fibroid inside the cavity of the womb can compromise the implantation of the fertilised egg and should be removed before starting fertility treatment. Also, fibroids may block one or both Fallopian tubes.
- Low sperm quality
Abnormal sperm count, motility or morphology is mostly unexplained. However, this could be related to factors such as a degree of testicular failure, undescended testis, abnormal chromosomal make up or a problem affecting the Y-chromosome which is the chromosome responsible for sperm production.
- Absence of sperm in the ejaculate (Azoospermia)
This could be due to obstruction of the tubes the sperm travel down to become part of the ejaculate (obstructive azoospermia). Another reason is testicular failure which is a problem of sperm production by the testis (non-obstructive azoospermia). Genital examination and a blood hormone test can differentiate between the two problems. Also, a blood test to check for the chromosomes, Y-chromosome microdeletion and cystic fibrosis are required before offering treatment to surgically retrieve sperm from the tubes and/or testis.