Assisted fertilization

IUI: Intrauterine insemination, what it is, when it is expected and success rates

Intrauterine insemination (IUI) consists of inserting a sample of seminal fluid into the uterus after appropriate preparation, through a specific catheter.

The IUI, intrauterine insemination is a minimally invasive medically assisted procreation technique , it is part of those defined level I techniques.

The purpose of IUI is to increase the number of sperm with a high percentage of normal forms at the fertilization site.

In fact, it allows the seminal liquid , suitably prepared, to be deposited closer to the oocytes , thus reducing the distance between the gametes and bypassing the vaginal acidity and any hostility of the cervical mucus.

The guidelines containing the indications of the procedures and techniques of medically assisted procreation of 2015 , ask to use in the first instance the simplest , least invasive and least expensive therapeutic options, taking due account of the age of the woman and the cause, when known, of infertility and sterility of the couple.

What are the first level techniques?

  • IUI on natural cycle : intracervical/suppervical insemination in natural cycle performed using semen preparation techniques;
  • IUI on induced ovulation: multiple ovulation induction associated with supracervical insemination performed using semen preparation techniques;
  • possible cryopreservation of male gametes.

In practice, IUI consists of inserting a sample of seminal fluid into the uterus after appropriate preparation, through a specific catheter.

This technique must be performed at the correct moment of the menstrual cycle under ultrasound and/or hormonal monitoring. To verify pregnancy, a blood test of beta HCG is required.

When is IUI used?

In order to use this method, some assumptions are necessary which must be carefully evaluated:

  • age of the woman and the finding of an adequate ovarian reserve ,
  • presence of at least one patent and functional tube
  • absence of intracavitary uterine pathologies
  • adequate number of motile and morphologically normal spermatozoa recovered after capacitation.

Semen capacitation is a treatment performed in order to select the “best” sperm by separating them from dead sperm, debris and other non-sperm cells, thus making them capable of fertilization.

Once these conditions have been met, intrauterine insemination can be used in the case of:

  • unexplained infertility;
  • mild to moderate male infertility;
  • stage I-II endometriosis and selected cases of stage III-IV of the American Fertility Society (AFS) classification, especially after surgery;
  • repeated failures of pregnancy induction with ovulation stimulation and targeted intercourse;
  • sexual and coital pathologies that have not found benefit from simple intracervical insemination;
  • cervical factor.
  • Prevention of the risk of transmission of infectious diseases in serodiscordant couples (HIV)

Attention, in case of multiple follicular growth induction ultrasound and/or hormonal monitoring is mandatory in order to reduce the risk of multiple pregnancies and severe ovarian hyperstimulation syndrome .

The advantage of IUI is that it is a non-invasive technique with a good cost-benefit ratio and can also be practiced by a second or third level infertility center.

On the other hand it does not have the same success rate as in vitro fertilization, it does not give information on the quality of oocytes and embryos, and there must be at least one functioning tube and acceptable sperm quality.

What are the parameters of male fertility that allow for the use of IUI?

In the guidelines for resorting to IUI it is specified that male infertility must be mild or moderate.

What are the references that can tell us if it is possible to resort to IUI with that seminal fluid?

In practice, the indispensable minimum number of motile spermatozoa  after preparation is 0.8 -5 million and as a percentage of physiological forms that of  4% according to WHO criteria.

How is an IUI performed?

Intra uterine insemination can be performed on a spontaneous cycle or following ovarian stimulation.

The steps are as follows:

  • spontaneous cycle or with pharmacological induction of ovulation
  • ultrasound and/or hormonal monitoring of follicular growth;
  • preparation of the semen sample observing the following indications: the collection container must bear the identification data of the person concerned; must be registered on a special form:
    • name, surname, date of birth of the female partner;
    • name, surname, date of birth of the male partner;
    • the period of abstinence observed; the time and place of collection (with particular regard for those samples that are not collected directly in the center);
    • the time elapsed between collection and preparation of the sample;
    • the following must also be recorded: the parameters of the semen, the method of preparation of the sample including in detail any possible variation from the standard laboratory product, the post-preparation sperm parameters;
    • possible evaluation of the semen to be donated (sperm sharing) for the purpose of heterologous assisted procreation;
  • introduction of sperm into the uterine cavity.

Ovarian stimulation (ovulation induction) is performed by administering clomiphene, or a combination of clomiphene and gonoadotropins , or gonadotropins alone, or aromatase inhibitors (letrozole), or gonadotropins and metformin, or clomiphene and metformin. The therapy must be decided by the medical team on the basis of the complete anamnesis of the couple.

In the case of stimulation, a single dose of hCG is usually administered 36 hours before ovulation in order to optimize follicle maturation and bursting.

IUI requires accurate transvaginal ultrasound monitoring to ensure correct administration of hCG and verify the number of follicles obtained by stimulation. Usually there must be one (or at most two) growths greater than or equal to 17mm in size.

In case of excessive ovarian response to stimulation and therefore with excessive production of follicles, IUI is postponed to avoid multiple pregnancies.

Success rates

The success of this technique depends on various factors, and not only on the age of the woman and the quality of the semen:

  • Cause of infertility
  • Age of partners
  • Duration of infertility
  • Treatment cycle
  • Seed parameters

The success rate therefore ranges from 2.7% to  20.5%.  

In Italy,  based on the most recent data contained in the 13th ACTIVITY REPORT OF THE ITALIAN NATIONAL REGISTER OF MEDICALLY ASSISTED REPRODUCTION    for IUI, there is a  10.7% pregnancy rate on cycles started.

In general the pregnancy rate per cycle is about 12% (Kalil et al,2001)

The cumulative pregnancy rate depends a lot on the problem that led the couple to resort to this first-level technique:

  • 12.3% for unexplained infertility
  • 16.4% for cervical mucus hostility
  • 10% for immunological causes
  • 21% for mild male infertility
  • 13.3% for ejaculatory failure

The chances of pregnancy are lowest after the third cycle of IUI , regardless of the method of ovulation induction

71% of IUI pregnancies occur in the first 2 cycles

85% of IUI pregnancies occur in the first 4 cycles

The IUI is not indicated in case of

  • Cervical atresia
  • Cervicitis
  • Endometritis
  • Closed tubes
  • amenorrhea
  • Severe oligospermia (number of spermatozoa < 1 million/ml)

What happens after the IUI?

Once the insemination has been completed, normal daily activities can be resumed.

Could occur:

  • abdominal discomfort, mild cramping pain.
  • Spotting, slight bleeding

Avoid intercourse if you have pelvic pain due to enlarged ovaries.

When to do beta HCG?

After 2 weeks of insemination.

If ovulation was induced with gonase, the pregnancy test could be positive even 12 days after administration.

Complications

This technique does not involve particular complications.

The main ones, in addition to uterine contractions and obviously the psychological impact of having to make use of external help to be able to conceive, are the complications of stimulation, represented by multiple pregnancy and ovarian hyperstimulation syndrome (OHSS) .

The risk of multiple pregnancy exists if the woman is under 30, has 6 mature follicles, estradiol > 1000 pg/ml (3671 pmol/L)

The risk of OHSS occurs mainly with gonadotropins, it is rare with stimulation with clomifen.

Centers typically expect a twin pregnancy rate of 10-15% and triplet pregnancy rates of less than 1%. More frequent twin pregnancies are usually due to inappropriate ultrasound monitoring.

It is therefore essential that the centers carefully take care of the correct administration of drugs and ultrasound checks.

IUI could also cause ectopic pregnancies and therefore many doctors propose precise ultrasound checks, at 6-7 weeks of gestation in patients with a positive pregnancy test.

Dr Kathryn Barlow

Kathryn Barlow is an OB/GYN doctor, which is the medical specialty that deals with the care of women's reproductive health, including pregnancy and childbirth.

Obstetricians provide care to women during pregnancy, labor, and delivery, while gynecologists focus on the health of the female reproductive system, including the ovaries, uterus, vagina, and breasts. OB/GYN doctors are trained to provide medical and surgical care for a wide range of conditions related to women's reproductive health.

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