Intra-uterine insemination (IUI), also known as artificial insemination, consists in placing selected sperm in the uterus. These sperm present excellent chances of fertilization and are previously isolated in the laboratory after collection of semen.
With this technique, Medicine only makes it easier for the sperm to fertilize the egg. Fertilization may not be occurring in an adequate manner for several reasons:
When using husband’s semen:
- Cervix factor – Some women secrete hostile cervical mucus which inhibits the passage of sperm. It is necessary for the sperm to overcome this barrier in order to swim freely towards the egg.
- Ovulatory factor – Ovulation is not always regular. Hormones may not be released at the right time or in the right amount to induce ovulation. When this occurs it becomes necessary to stimulate and monitor ovulation, as well as place sperm close to the egg in the tube.
- Slight male factor – To obtain spontaneous fertilization of the egg around 100 thousand extremely mobile sperm are necessary in the egg micro-environment. Reduction in the number or motility of sperm may result in an inadequate number reaching this environment. Preparation of semen and placement of top quality sperm in the uterus close to the tubes may solve this problem.
- Slight and moderate endometriosis – This disease affects 35% of fertile women and the meeting of the egg and the sperm may be jeopardized by the inflammation caused by the disease. In many of these cases fertilization may be optimized through intra-uterine insemination.
- Immunological factor – Anti-sperm antibodies interfere with fertilization. The preparation of semen may free a good number of sperm of attached antibodies. This procedure followed by the placement of sperm near the ovulation site optimizes fertilization.
When using donor’s semen:
- Absence of sperm
- Single woman
- Repeated pregnancy loss due to genetic factor
- HIV serodiscordant couple