Is the IUI process more painful

IUI: Intrauterine Insemination

What is an IUI?

Intrauterine insemination is one of the oldest reproductive medicine techniques. With the help of a syringe and a long, thin tube (catheter), the semen is introduced directly into the uterus at the perfect time, i.e. immediately after ovulation. There used to be two other variants: In one case, the sperm was only introduced up to the cervix (intracervical), in the other only in the vaginal entrance (intravaginally). However, both methods are no longer practiced today.

The semen sample for the IUI can come from one's own husband (homologous insemination) or a donor from another person (heterologous insemination).

How does an IUI work?

First, the semen sample is prepared in the laboratory for the IUI. The further course of the IUI depends on whether the woman has a normal monthly cycle or whether ovulation has to be artificially induced.

Semen sample

Frozen (cryopreserved) or fresh semen obtained on the day of intrauterine insemination by masturbation are suitable for the IUI.

Before the IUI, the sperm must be cleaned in the laboratory and separated from the semen. This is important because the semen sample contains substances that can impair the success of the implantation (germs, prostaglandins, cytokines).

In addition, in these initial processing steps, the doctors try to optimize the number of sperm cells in order to obtain as many fertilizable sperm cells as possible from the ejaculate even with a low number of sperm cells. Most laboratories use the so-called "swim-up" method for this. A layer of culture medium is poured over the seminal fluid, into which only the mobile sperm swim. After this procedure, between 200 and 300 microliters of cell suspension with potent sperm cells are ready for the IUI.

IUI procedure without hormone treatment (spontaneous cycle)

If the woman has a normal, spontaneous cycle, the semen is transferred at the time of ovulation: between the 11th and 13th day of the cycle, the doctor uses vaginal ultrasound to check the maturation of the follicles and the structure of the uterine lining. If everything is ready for the fertilized egg to implant and if the hormone concentration in the blood (estrogen, progesterone, LH) indicates that ovulation is imminent, the IUI can begin.

IUI procedure with hormone treatment (induced ovulatory cycle)

In the event of menstrual cycle disorders or if the partner's sperm quality is not optimal, the doctor recommends hormonal treatment for the woman before intrauterine insemination: The hormones, which are administered in the form of injections (gonadotropins) or tablets (clomiphene), stimulate the maturation of follicles (follicles) ) in the ovaries. This should increase the IUI success.

Whether and to what extent the egg cells respond to the hormonal stimulation can be checked using ultrasound through the vagina (vaginal) and a blood analysis of the hormone level. If the egg is large enough (15 to 20 millimeters), the doctor triggers ovulation hormonally (ovulation induction). The actual insemination must begin immediately afterwards, but at the latest within 36 hours.

IUI process

The doctor administers the prepared sperm with a syringe and through a thin catheter, which he pushes vaginally directly to the uterus. Intrauterine insemination is usually painless and uncomplicated and only takes a few minutes. If you lie there for a while after that, it will increase the chances of IUI success.

Who is an IUI suitable for?

Semen transfer is suitable for couples in whom, after a thorough examination, no serious causes for childlessness can be determined (idiopathic sterility).

In women, menstrual cycle disorders, endometriosis, anatomical changes in the cervix or poorly permeable cervical mucus may make fertilization more difficult. In men, it can be due to a low sperm count, slow sperm or a lack of ejaculation if the child's witness does not work.

Sometimes it is also necessary to avoid direct sexual contact, for example with couples who are infected with HIV. Even then, intrauterine insemination can fulfill the desire to have children.


Simply transferring semen is not enough, however. Both men and women must meet some organic requirements.

For women these are:

  • continuous functional fallopian tubes (tube function)
  • uterine mucus has built up sufficiently for implantation
  • Ovulation (spontaneous or hormonally induced)

The man needs:

  • fertilizable (potent) sperm
  • motile sperm
  • Sufficient sperm count in the sperm analysis (otherwise an intracytoplasmic sperm injection, ICSI may be more useful)

In a detailed consultation, you should clarify with your doctor whether nothing stands in the way of an IUI treatment (physical resilience, age of the woman, costs).

IUI: Chances of Success

The success rate per treatment cycle and with hormonal stimulation of women is around seven to 15 percent. After several treatment cycles, up to 40 percent can be achieved. However, only up to a woman's age of about 35 years. In older women, the chances of conceiving with 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 the IUI, it is essential to have stimulated follicles. If more than two follicles mature, however, the risk of multiple pregnancy increases, which is why doctors advise against insemination in this case.

Repeated insemination within a cycle does not bring any additional benefit, as IUI studies have shown. Multiple inseminations are therefore not used today.

How often a couple should try to get pregnant using IUI also depends on the woman's age. Around 80 percent of couples become pregnant after three to four cycles. If the woman is younger, she and her partner can try it for a while. Doctors recommend a maximum of six attempts. However, women over 35 should not waste too much time after the first unsuccessful cycles and think about other methods of artificial insemination in good time. Perhaps, for example, in vitro fertilization (IVF) or ICSI have a better chance of success.

Advantages and disadvantages of the IUI

The advantage of the IUI method is that many potent sperm cells enter the uterus at the perfect time. This increases the chances of getting pregnant.

If hormone treatment is necessary as part of the IUI, it must be 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 the result, with an increased risk for mother and children. In the worst case, ovarian hyperstimulation syndrome develops, which is associated with pain, water retention in the abdomen, breathing problems or nausea and can become life-threatening.

The real one Intrauterine Insemination (IUI), i.e. pure semen transfer, is relatively uncomplicated to carry out, inexpensive, safe and usually does not cause any pain.

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