What is IUI?
Intrauterine insemination is one of the oldest reproductive techniques. It involves using a syringe and a long thin tube (catheter) to deliver semen directly into the uterus at the perfect time, just after ovulation. In the past, there were two other variants: In one, the sperm was inserted only as far as the cervix (intracervical), and in the other, only into the vaginal entrance (intravaginal). However, both methods are no longer practiced today.
The sperm sample for IUI can come from the patient’s own husband (homologous insemination) or from a foreign donor (heterologous insemination).
What is the procedure for IUI?
First, the sperm sample is prepared for IUI in the laboratory. The rest of the IUI procedure depends on whether the woman has a normal menstrual cycle or whether ovulation has to be induced artificially.
Semen sample
Frozen (cryopreserved) or fresh semen obtained by masturbation on the day of intrauterine insemination is suitable for IUI.
Before IUI, the semen must be cleaned and separated from the seminal fluid in the laboratory. This is important because the semen sample contains substances that can affect the success of implantation (germs, prostaglandins, cytokines).
IUI procedure without hormone treatment (spontaneous cycle).
If the woman has a normal, spontaneous cycle, sperm transfer takes place at the time of ovulation: approximately between the 11th and 13th day in the cycle, the doctor checks follicle maturation and the structure of the uterine lining via a vaginal ultrasound. If everything is ready for implantation of the fertilized egg and the hormone concentration in the blood (estrogen, progesterone, LH) indicates impending ovulation, IUI can begin.
IUI procedure with hormone treatment (induced ovulatory cycle).
In case of cycle disorders or if the partner’s sperm quality is not optimal, the doctor recommends hormone treatment to the woman before intrauterine insemination: the hormones, administered in the form of injections (gonadotropins) or tablets (clomiphene), stimulate the maturation of follicles in the ovaries. This is thought to increase IUI success.
Whether and to what extent the eggs respond to hormonal stimulation can be checked by ultrasound through the vagina (vaginal) and by blood analysis of hormone levels. If the egg is large enough (15 to 20 millimeters), the doctor triggers ovulation hormonally (ovulation induction). Immediately afterwards, or within 36 hours at the latest, the actual insemination must begin.
IUI procedure
For whom is IUI suitable?
Sperm transfer is suitable for couples in whom no serious causes of infertility can be identified after a thorough examination (idiopathic infertility).
In women, fertilization may be hampered by cycle disorders, endometriosis, anatomical changes in the cervix or cervical mucus that is difficult to pass. In men, it can be due to a low sperm count, slow sperm or a lack of ejaculation if childbearing does not work out.
Sometimes it is also necessary to avoid direct sexual contact, for example in couples affected by HIV infection. Even then, intrauterine insemination can fulfill the desire to have a child.
Requirements
Simply transferring sperm is not enough, however. Both man and woman must meet some organic requirements.
For the woman, these are:
- continuous functioning fallopian tubes (tubal function)
- sufficiently built up uterine mucus for implantation
- ovulation (spontaneous or hormonally induced)
The man needs:
- fertilizable (potent) spermatozoa
- motile sperm
- sufficient sperm count in the spermiogram (otherwise intracytoplasmic sperm injection, ICSI may be more appropriate)
IUI: Chances of success
The success rate is about seven to15 percent per treatment cycle and with hormonal stimulation of the woman. After several treatment cycles, even up to 40 percent can be achieved. However, only up to an age of about 35 years. In older women, the prospect of pregnancy via intrauterine insemination drops to four percent per cycle.
The drug used for hormonal stimulation and the number of stimulated follicles also play a role. To be successful with IUI, stimulated follicles must be present. However, if more than two follicles mature, the risk of a multiple pregnancy increases, which is why doctors advise against insemination in this case.
Multiple inseminations within a cycle do not provide any additional benefit, as IUI studies have shown. Multiple inseminations are therefore not used today.
Advantages and disadvantages of IUI
Advantage of the IUI method is that at the perfect time, many potent sperm cells enter the uterus directly. This increases the chances of pregnancy.
If hormone treatment is necessary as part of IUI, it is essential that it is carefully monitored by a doctor (using ultrasound and hormone analysis). This is because overstimulation can occur, causing more than two to three follicles to mature at the same time. Multiple pregnancies are then the result, with an increased risk for mother and children. In the worst case, an ovarian hyperstimulation syndrome develops, which is associated with pain, water retention in the abdomen, breathing problems or nausea and can become life-threatening.
However, the actual intrauterine insemination (IUI), i.e. the pure sperm transfer, is relatively uncomplicated to perform, inexpensive, safe and usually does not cause any pain.
