Intrauterine insemination (IUI) is in essence the direct injection of spermatozoa into the inner cavity of the uterus (endometrium) and aims at increasing the number of sperm that enter the fallopian tubes therefore improving the chances of egg fertilisation. Whether a semen specimen is disposed raw or thawed from a frozen cohort for insemination, it must be processed for separating the motile spermatozoa from the rest of the constituents of the ejaculate. If raw semen is introduced into the uterus then certain compounds namely prostaglandins which are present in the seminal fluid will cause it to contract and expel the inseminated sperm. Moreover such practice is associated with increased risks for infection.
There are two conventional methods for processing semen specimens for insemination. The simplest and commonest approach is the wash and swim up technique where the ejaculate is diluted in specialty culture media (containing mainly water, salt solutions, albumin protein, antibiotics and energy producing ingredients – sodium pyruvate) before is centrifuged to concentrate all cellular components inclusive of sperm. The pellet which forms is carefully layered with fresh culture medium where motile spermatozoa can swim. Following approximately 1 hour of incubation at standard conditions (36°C at 6% CO2 in air and 99% humidity) the swim up product is concentrated again using centrifugation prior to becoming available for the insemination procedure. The swim up technique is more effective with specimens of optimal count and motility. An alternative approach is the discontinuous gradient centrifugation technique where colloidal suspensions of different viscosity are layered superimposed into a sterile culture tube and the seminal fluid is positioned on the top. Separation is based on size and density, with larger and denser particles forming residues at lower centrifugal forces. This technique is more suitable for poorer quality semen specimens although it works well with good samples too.
IUI can be implemented during a natural cycle or following controlled ovarian stimulation similarly to the timed-intercourse approach. It is more beneficial to younger couples when the major cause of infertility is low sperm count and/or suboptimal motility but it can also be advantageous to couples where the cause of infertility could not be elucidated following preliminary assessment, when anti-sperm antibodies have been diagnosed in the cervical mucus and to candidates presenting ovarian dysfunction due to polycystic ovarian condition. This approach to treatment is not suitable for recipients with blocked fallopian tubes.
A fine and flexible catheter is firstly introduced through the cervical canal into the uterus. Once the correct position of the catheter has been confirmed with the use of abdominal ultra sound scanning the sperm suspension is injected with the use of a syringe into the endometrium. The successful implementation of the procedure can be visualised on the monitor of the ultrasound scanner at the time.
An obvious disadvantage of IUI in stimulated cycles is the likelihood of multiple pregnancies and their associated risks, such as ovarian hyperstimulation, premature labour and increased rates of miscarriage.
Success rates using IUI vary with recipient’s age, fertility manifestation and whether the treatment incorporates ovarian stimulation or managed through a natural cycle. While these variables are important denominators for a successful outcome a maximum rate of 20% should be contemplated for each fresh attempt. The standpoint of Genesis is that IUI does not substantially improve the chances of conception when compared to timed-intercourse when the male partner’s semen quality is optimal