What is IUI?
Intrauterine insemination (IUI) is a procedure in which processed sperm sample is placed inside a woman’s uterus. The objective of IUI is to increase the number of motile sperm that reaches the egg in the fallopian tubes to facilitate fertilisation. It is usually the first-line approach for couples seeking assisted reproductive treatment.
Timing for IUI
For a successful insemination, it is important to time the IUI accurately—when the egg has ovulated into the fallopian tubes. IUI is done either in a natural cycle or an ovarian-stimulated cycle.
In a natural cycle, the timing of ovulation is predicted using a ovulation predictor kit that measures the LH surge. If the test returns positive, the insemination is done the next day. Alternatively, a hCG trigger for ovulation can be used.
In a stimulated cycle, medication such as clomiphene citrate, letrozole or FSH is administered to promote follicular growth. When the follicles grow to a certain size, a hCG injection trigger is given to induce maturation and ovulation. The IUI is then performed 36 hours post-hCG.
Another strategy is to have two inseminations per cycle to increase the window of fertilisation. This procedure is termed ‘Double IUI’.
Success rates for IUI
The success rates of IUI depend on several factors:
- Female factors such as age, ovarian function, fallopian tube blockage, endometriosis, uterine abnormalities and other related factors.
- Male factors such as sperm parameters. A higher number of progressively motile sperm favours the chances to pregnancy.
- The timing of insemination.
How is IUI performed?
The semen sample is collected through masturbation into a sterile container. If the male spouse is unable to provide a sample in the clinic, he is permitted to produce at home or use a non-spermicidal condom. However, the semen sample must arrive at the clinic within an hour and submitted in person.
Semen collection is scheduled approximately 2 hours before the IUI treatment. The laboratory uses this time to process the semen sample and prepare a final sample with highly motile sperm.
Insemination is then completed within a couple of minutes with minor discomfort. The clinician inserts a small catheter into the uterine cavity through the cervix and releases the processed sperm sample. Following the procedure, the patient is able to resume normal daily activities.
Difficult IUI procedures
In certain cases, it can be difficult to manoeuvre the catheter into the uterus. This may be due to the anatomical position of the uterus or a narrow cervix.
To overcome this, the clinician uses a catheter which is fitted with a flexible wire to increase rigidity and allow bending of the catheter to specific shapes. Apart from that, the clinician may use a tenaculum to get a hold of the cervix and straighten the angle between the cervix and uterus. This makes it easier for the catheter to pass through. These interventions may cause more discomfort.