What is Intrauterine Artificial Insemination?

By (embryologist) and (babygest staff).
Last Update: 10/24/2019

Artificial insemination or intrauterine insemination (IUI) is defined as a simple, low-cost assisted reproductive technique. It consists of depositing the semen sample inside the woman's uterus. The sperm used can be from the couple or from a donor. Although its effectiveness is not high, it is the reproductive solution for many couples with infertility.

In this article we discuss the main features of this technique, as well as the types and steps followed to carry it out.

Indications and requirements

Due to its simplicity, IUI is not a suitable technique for many reproductive problems. It is only used when there are fertility alterations in which the main problem is that the sperm are not able to reach the egg to fertilize it.

Some common examples are:

  • Mild male Sterility: low-severity alterations in seminal quality
  • Inability to deposit semen in the vagina: impotence, retrograde ejaculation, vaginal dysfunction, etc.
  • Sterility of unknown origin.
  • Mild female infertility: low-grade endometriosis, alterations of the cervix, uterine problems or malformation, etc.

When there’s no male partner, a serious infertility of the male or genetic alteration likely to be inherited by the offspring, artificial insemination of the donor may be performed.

In any case, for both the homologous insemination and the donor insemination, IUI can only be applied if the woman meets the following requirements:

  • Being over 35 years of age
  • Having the capacity to ovulate
  • Having tubal permeability, meaning that the fallopian tubes are functional (the fallopian tubes are the place where the natural union of egg and sperm occurs).
  • Having a good ovarian reserve.

In the case of men it is necessary that they do not suffer from any contagious disease (HIV, syphilis, hepatitis...) and that their sperm sample has a motile sperm count greater than 3 million motile sperm. If this requirement is not met, it will be possible to perform IUI with donor sperm.


Although artificial insemination is generally known as intrauterine insemination, there are other types of AI depending on where sperm are deposited: intratubal (fallopian tubes), intracervical (cervix or cervix), intravaginal (vagina), or intrafollicular (ovarian follicle).

These rates apply only in specific cases where IUI cannot be performed. For this reason, when we refer to Insemination without any other qualifier, we speak of intrauterine.

There are also two types of artificial insemination depending on the origin of the semen:

  • Heterologous or donor artificial insemination (DI): a sperm sample from a healthy young boy who has decided to donate part of his male gametes (sperm) is used to allow another person or couple to undergo assisted reproductive treatment. Thus, the genetic endowment of the child born of the donation will not be that of the future father but that of the donor.
  • Homologous artificial insemination (AIH): the sperm deposited in the patient comes from her partner. Therefore, the child will share the genetic burden of both parents.

Surrogacy is the assisted reproduction treatment that generates the most deception and doubts. Therefore, it is essential to choose a clinic and an agency that transmits transparency and avoids deception.

How is intrauterine insemination performed?

The steps to follow to perform an artificial insemination are simple. In fact, no hospital admission or anesthesia is required. It is usually performed in the gynecological practice itself and lasts about 10 minutes.

The procedure is as follows:

Controlled ovarian stimulation

The patient is given mild hormonal medication subcutaneously so that the ovary is able to produce one to three mature eggs in the ovarian follicles (structures of the ovary where the eggs grow and mature before ovulation).

Thus, we control the exact moment of ovulation (expulsion of the egg) and increase the possibilities with respect to a natural cycle.

It is essential to have a rigorous control of the stimulation to avoid multiple pregnancies (twins, triplets...). For this reason, the doses of medication are soft and the patient undergoes continuous ultrasound and analytical controls during the time that the stimulation lasts (from 7 to 10 days)

Ovulation induction

Once the specialist considers that these follicles have the right size, about 16-18 millimeters, is administered the hormone hCG that is responsible for triggering ovulation about 36 hours after its application.

It will be at that time when the insemination is programmed to facilitate the encounter between egg and sperm.

Capacitation of the sperm sample

The sperm sample, collected by masturbation after a period of sexual abstinence of between 3 and 5 days, undergoes a preparation process known as sperm capacitation.

It consists of the sample of the best spermatozoa, eliminating the seminal plasma and those spermatozoa with bad qualities (mobility, vitality, etc.).

Thus, the already capacitated sample will contain the spermatozoa with the best characteristics, i.e. those with the greatest fertilizing capacity.

If the semen is from a donor, it will have been previously processed and, therefore, it will only be necessary to thaw it, as all donor semen samples are frozen for at least 6 weeks.

Intrauterine insemination

Intrauterine insemination does not require any special treatment. The processed semen sample (normally 0.5 ml) will be introduced into the insemination cannula. Then, when the patient is in a gynecological position, the insemination cannula is passed through the cervix and once the cervix is reached, the contents of the cannula are discharged with the capacitated sperm.

The woman will rest in the practice afterwards for 15-30 minutes. After this time she will be able to return to her daily routine but always avoiding great efforts.

Supporting the luteal phase

After insemination, the patient will receive hormonal medication (different from stimulation) to prepare the endometrium and thus promote implantation.

The medication used is progesterone, which is usually administered in the form of vaginal ova or tablets, and not subcutaneously (injections) as is the case with medication for stimulation.

Once the insemination has been carried out, we wait 15-17 days to carry out a pregnancy test and find out what the result has been.

Advantages and disadvantages

Among the main advantages of artificial insemination, we highlight the following:

  • Simplicity: it does not hurt, does not require anesthesia, the duration is short and does not require instruments or specific machinery.
  • Low cost: being a simple technique, its costs are low. The homologous insemination usually costs between 300 and 800 $; Using insemination with donor sperm may vary in price.
  • It is very similar to the natural process.
  • Ovarian stimulation is gentle, as the doses of medication are low.
  • Few associated risks.

Despite these advantages, the low success rate and stringent requirements mean that it is not the ideal technique for many women and couples.

In addition, artificial insemination does not allow the use of egg donation.

Potential Risks

As mentioned above, artificial insemination is a low-complexity technique and therefore serious problems or complications do not usually arise. In any case, it is not completely risk-free.

The main problems that can arise are:

  • Ovarian Hyperstimulation Syndrome (OHSS): This is uncommon due to the low doses of hormonal medication used and the rigorous controls of the stimulation process. This is an excessive response of the body to ovarian stimulation that can lead to different symptoms in women.
  • Ectopic pregnancy: also known as extrauterine pregnancy, occurs when the embryo implants in a place other than the uterine endometrium, the most common being the fallopian tubes. There is a 4% risk with artificial insemination, whereas in a natural cycle it would be 0.8%.
  • Multiple pregnancy: either twin pregnancy, triplet pregnancy, etc. In this sense it is essential to adequately control the stimulation, because if there is spontaneous ovulation of more than one egg, the risk of double pregnancy is greater.
  • Abortion: the probability is approximately 20%

Results and likelihood of pregnancy

The probability of success of artificial insemination depends on a number of factors including the age of the patient, the quality of the sperm used, the cause of infertility or the qualities of the uterus.

Apart from that, results vary from clinic to clinic. Despite this, a number of overall success rates are established. Thus, a woman under the age of 35 has a 13 to 25% chance of achieving pregnancy if she uses her partner's semen and between 18 and 29% if the semen used comes from a donor.

Besides, there is the so-called cumulative success rate. This means that the probability of pregnancy increases when consecutive inseminations are performed, up to a maximum of 4.

If the pregnancy does not come after 4 artificial inseminations, it will be time to consider other reproductive paths to achieve gestation such as in vitro fertilization.

The cumulative pregnancy rate in these four cycles of homologous insemination is 50-60% and 60-70% if performed with sperm donation.

FAQs from users

Why isn't artificial insemination done to reduce the price of surrogacy?

By Andrea Rodrigo (embryologist).

Generally, and this is what is recommended, surrogacy is performed through in vitro fertilization (IVF), as this reduces the genetic link between the pregnant woman and the baby who is pregnant. In addition, in this way, the future mother can provide the eggs for the creation of the embryo that will give rise to the birth of her child, in other words, mother and child will be able to share the genetic load.

Surrogacy through artificial insemination is known as traditional surrogacy.

What is the difference between artificial insemination and in vitro fertilization?

By Andrea Rodrigo (embryologist).

The main difference between both assisted reproduction techniques is that in AI, fertilization takes place inside the female reproductive tract, while in IVF, fertilization takes place in the laboratory and it is later when the embryos created in vitro are transferred to the woman's uterus.

In addition, the ovarian stimulation doses are different as well as the requirements and indications, among other aspects.

What are the symptoms of a pregnancy through AI?

By Andrea Rodrigo (embryologist).

The symptoms of pregnancy are not different if it has been achieved naturally or through a process of assisted reproduction such as artificial insemination. It is possible that the hormonal medication used for the treatment slightly alters the symptoms, but in general, they are the same.

It is important to note that there is a lot of variety in terms of pregnancy symptoms between women and also between pregnancies of the same woman. You can read more about this here: What are the most common Symptoms of Pregnancy?

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inviTRA.com, 2019: What is artificial insemination (AI)? -Process, Cost & Types. Antonio Forgiarini, Patricia Recuerda y Rebeca Reus, https://www.invitra.com/en/artificial-insemination-ai/

inviTRA.com, 2019: What is assisted reproductive technology (ART)? Techniques & Costs. Blanca Paraíso, Miguel Dolz, Sara Salgado y Zaira Salvador, https://www.invitra.com/en/assisted-reproduction/

FAQs from users: 'Why isn't artificial insemination done to reduce the price of surrogacy?', 'What is the difference between artificial insemination and in vitro fertilization?' and 'What are the symptoms of a pregnancy through AI?'.

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 Andrea Rodrigo
Andrea Rodrigo
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia along with the Valencian Infertility Institute (IVI). Postgraduate course in Medical Genetics. More information about Andrea Rodrigo
Adapted into english by:
 Romina Packan
Romina Packan
Babygest Staff
Editor and translator for the Babygest magazine in English and German. More information about Romina Packan

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