Tubal Infertility
IVF was originally developed to help women whose fallopian tubes are blocked and for whom surgery to overcome the blockage is not possible, or unsuccessful. It is now also used for:

Endometriosis
This is a condition when the tissue that lines the uterus (called the endometrium) is found outside of the uterus. It is 'trapped' in the pelvic area and can affect the ovaries, uterus, and nearby structures. It often causes lower abdominal pain and/or painful periods. This condition is often associated with infertility even when the tubes are open and the woman is ovulating regularly.

Unexplained Infertility
Couples who have been fully investigated and for whom no cause for fertility problems is found.

Male Factor
Current assisted reproductive techniques have meant that egg fertilisation can be achieved with very low numbers of motile ejaculated sperm and even sperm surgically retrieved from the testicles. 

Ovulatory Disorders
Where an egg is not released from the ovary (ovulation) naturally/regularly.

If you wish to read more general information regarding fertility issues you can go to the following link