Intrauterine insemination (IUI) is very often the first assisted reproduction procedure used in the treatment of infertility. The principle of homologous IUI is based on the injection of the husband's sperm into the woman's uterine cavity.
The purpose of the IUI is to make it easier for the sperm to meet the egg and thus increase the chances of pregnancy. IUI is a simple procedure that can be used in certain situations:
- Unexplained infertility.
- Infertility related to certain female medical causes (e.g. minimal to mild endometriosis with at least one patent fallopian tube, previous cervical surgery, etc.).
- Male infertility associated with mild to moderate reduction in sperm concentration and/or motility.
- Infertility due to the impossibility of having sexual intercourse (e.g. erectile dysfunction, vaginismus, psychogenic factors, etc.).
The IUI process requires the control of two parameters essential to its success: the moment of insemination and the preparation of the spermatozoa.
Thetime of insemination
In order to allow spermatozoa to meet the egg, IUI must be performed close to ovulation. To determine when the expulsion of the egg will take place, there are two main methods of synchronization: the urine ovulation detection test or an ultrasound monitoring of the maturation of the ovarian follicles.
The urine ovulation test is the easiest and most convenient method. This test is available at Fertilys, in pharmacies or in supermarkets. It can usually be done at home. The principle of this test is based on the detection of the level of luteinizing hormone (LH) in the urine. An LH surge usually occurs 24 to 36 hours before ovulation, allowing you to estimate when the egg can be fertilized.
Ovulation can also be determined by ultrasound monitoring. Thanks to a series of ultrasounds, we can thus visualize the number of ovarian follicles that are developing and observe the evolution of their size. When a dominant follicle reaches a size between 18 and 25 mm, ovulation can be artificially triggered using an injection of the hormone chorionic gonadotropin (hCG). The hCG indeed mimics a pre-ovulatory LH peak. The hCG will thus induce ovulation instead of the naturally secreted LH. As ovulation takes place approximately 36 hours after the injection, an appointment for IUI is scheduled the next day or two.
Preparation of spermatozoa
During IUI, the sperms are deposited directly into the uterine cavity, allowing them to pass through the cervix without difficulty. To do this, the sperm must first undergo adequate preparation which will ensure better success during insemination.
When the sperm sample is produced by the spouse, it must first be liquefied before processing. It is generally recommended to produce the sample on site at the clinic. It is then placed in an incubator at 37oC for 30 minutes to allow it to liquefy.
If the sample is produced at home, it should be transported at body temperature, under the armpit or on the stomach, to optimally maintain its integrity and allow it to liquefy. In the laboratory, after liquefaction, a drop of the sample is first placed on a counting slide which allows the concentration and mobility of the spermatozoa to be assessed under the microscope. The rest of the sample is deposited on a solution, in the form of increasing density gradients, which will allow the mobile spermatozoa to be concentrated in the bottom of the tube, by centrifugation (Figure 1). Once concentrated, the mobile spermatozoa are deposited in a washing solution which makes it possible to eliminate the impurities and the seminal liquid. You should know that the seminal fluid must be eliminated from the preparation since it can cause uterine contractions and expose the woman to more thanrisk of pelvic infections following insemination. When finished, the solution containing the motile sperm is drawn into a flexible tube called a “catheter”. The insemination will then be performed by the doctor and the sperm will be deposited in the uterine cavity through the catheter (Figure 1). Catheter insertion is directed after insertion of a speculum, and the procedure generally produces no major discomfort.
When combined with ovulation stimulation, IUI is more likely to be successful. According to studies, the success rates in insemination vary between 10 and 15%. A third of women under the age of 40 will become pregnant during their first 3-4 insemination cycles. If no positive result is observed after these insemination cycles, in vitro fertilization is then considered.
By Rachel Richard, biochemistry laboratory technician at Fertilys, T. M, R. T
Fabien Joao, biochemistry laboratory technician at Fertilys, M. Sc.
