IUI intrauterine insemination: what it is and how it works

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Philippe Gloaguen
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IUI intrauterine insemination

L'intrauterine insemination (IUI) it is one of the simplest methods of assisted reproduction, crowned with success especially when it is associated with hormonal induction of ovulation. Let's see how it works, what are the chances of success and the testimonies of those who managed to become a mother with this technique.

In this article

  • What's this
  • Cost
  • Controindicazioni
  • Success rates 
  • Testimonials

What's this

The IUI is one XNUMXst level technique of medically assisted procreation which consists in the introduction of treated male gametes into the uterine cavity. This increases the chances that the sperm will be able to meet and fertilize the egg in the fallopian tubes. IUI can be performed with the partner's (homologous) or donated (heterologous) gametes.

IUI is indicated when the spermatozoa are unable to penetrate through the cervical mucus. However, IUI is increasingly being used successfully to treat:

  • Infertility with no clear cause;
  • mild endometriosis;
  • presence of antisperm antibodies;
  • male infertility with poor quality sperm production.

In the simpler version of the IUI technique, the spermatozoa are introduced directly into the uterus through a thin catheter, shortly after the time of natural or induced ovulation. The seminal fluid can be obtained from the partner or it can come from a donor (not in Del Paese, where this practice is prohibited by law 40/2004). Semen is always "treated" in the laboratory with a process called capacitation. This means:

  1. Washing to separate the seminal fluid from the spermatozoa; the first, in fact, contains proteins and prostaglandins (possibly also bacteria) that can cause immune reactions, uterine contractions and infections. The seminal fluid also contains inhibitory factors that prevent the full development of spermatozoa
  2. selection of spermatozoa with normal shape and greater motility.

Since conception occurs naturally after IUI (in the fallopian tubes), it is very important that the woman does not have anatomical anomalies that could prevent the oocytes from reaching the uterus.

Read also: ICSI


In an assisted reproduction clinic or center, the IUI costs approx 750 €, while in public centers you only pay the ticket.


The main contraindications at the IUI are:

  • Age of the woman over 40 years
  • Tubal sterility
  • Severe endometriosis (Stadio III-IV)
  • Failure of previous IUI attempts

Success rates

IUI can successfully treat infertility caused by antisperm antibodies present in the cervical mucus.

The probability of success for a single cycle is 10-15% and reaches about 25% after 6 IUI attempts, provided that both sperm and fallopian tubes are normal. As with other fertility treatments, IUI tends to be more successful in young women. On average it is estimated that within 4 attempts 85% of successes are achieved: after which it is passed to in vitro fertilization. 


Here is the story of a mother who managed to fulfill her dream thanks to intrauterine insemination: after a year of failed attempts and the diagnosis of varicocele for her husband, the couple turned to a specialized clinic. 

Our last intercourse was two days before the operation, then we did the "iui" (intrauterine insemination). At that moment I prayed. In the meantime, they called my husband for surgery. After a few days, I took the beta Hcg test. They were positive!


  • Intrauterine insemination

  • assisted fertilization
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