Assisted fertilization: what it consists of

What does assisted fertilization consist of?

“Assisted fertilization” is not an absolute concept, but a sort of “umbrella expression” which contains within it various techniques and variants, all aimed at conception.

The Ministry of Health speaks of  Medically Assisted Procreation (MAP) and explains that this includes “all those procedures that involve the treatment of human oocytes, sperm or embryos as part of a project aimed at achieving a pregnancy”. Sometimes, in fact, as is known, there are personal stories or physiological situations that prevent you from achieving the goal of a pregnancy in the traditional way. In these cases, the use of one of the different PMA techniques can allow the dream of having a child to come true.

Who is Assisted Reproduction (MAP) indicated for?

Medically assisted procreation can be used in all those cases in which spontaneous conception has proved impossible, or remote, despite the use of specific treatments or drugs. The cases are varied: they range from full-blown infertility to cases in which, despite the lack of apparent causes, attempts to conceive are unsuccessful despite long periods of attempts, from sperm values ​​that are too low in men to women with blocked tubes or too much damaged.

In all cases, before evaluating whether to resort to assisted procreation and eventually deciding which procedure to apply, the available data will also have to be cross-referenced with those relating to the woman’s age and the time to seek conception, as well as obviously other personal characteristics such as body mass, ovarian morphology and any pathologies.

In vivo and in vitro (first and second level)

Generally, two levels of PMA are identified. The so-called  first level assisted fertilization  includes the whole set of techniques and methods carried out “in vivo”, ie inside the female body.

On the other hand, the so-called “in vitro” techniques are of  second level  , ie when fertilization – or rather the meeting between sperm and oocyte – takes place outside the body, in the laboratory. The doctor who performs it and the reproductive assistance facility will take care, after careful diagnosis and interviews, to establish from time to time whether to prefer in vivo fertilization or opt for in vitro fertilization, and from there move towards the specific technique .

There is also, much rarer, third-level fertilization  , which includes procedures that represent a real operation, complete with hospitalization and complete sedation. We will not go into the merits of the latter in this article, limiting ourselves to mentioning the techniques that include: laparoscopic intratubal transfer of male and female gametes (GIFT), microsurgical collection of gametes from the testicle and laparoscopic oocyte retrieval.

The main forms of fertilization

Among the main forms of ART performed in vivo are  ovarian stimulation  and intrauterine insemination .

The first, which can be a treatment on its own or the first part of a more complex programme, consists of a hormonal therapy aimed at inducing ovulation, or more specifically the maturation of several ovarian follicles, all aimed at having more oocytes for fertilization. Ovarian stimulation by subcutaneous route, with daily injections (for 14-day cycles) that can be done alone.

Intrauterine insemination instead involves, after the subcutaneous introduction of a follicle-stimulating hormone, the transfer into the uterus through the use of a catheter of the sperm previously treated in the laboratory, during the periovulatory period: the idea is to make it more the path of the sperm towards the oocytes is short and easy, favoring the meeting of the gametes for the purpose of conception. It is a rather simple and not particularly invasive technique.


Among the main in vitro ART techniques, we find above all IVF and ICSI, two methods of conception with a similar starting point and some significant differences.

IVF, which stands for “in vitro fertilization with embryo transfer”, allows the encounter between the sperm and the embryo outside the uterus, passing through different phases: after a phase of ovarian stimulation, we move on to the “Pick-up ”, the collection of oocytes through transvaginal collection, and parallel to the collection of seminal fluid, to then proceed to in vitro fertilization and, subsequently, after a period that can vary, to the transfer of the embryo into the uterus, while the remaining embryos are frozen.

ICSI (acronym for  Intracytoplasmic Sperm Injection , or intracytoplasmic injection of sperm) differs from the previous practice because in this case the meeting between the gametes takes place mechanically, precisely by directly injecting the sperm into the egg in a test tube, while the subsequent phases are analogous.

More recent than IVF, the ICSI technique is generally preferred in cases of male infertility. In any case, as always, it will be the specialist center you go to to recommend the most appropriate procedure depending on the case.

Homologous and heterologous

In addition to the distinction between in vivo and in vitro, when the macro-categories of assisted fertilization are outlined, there is also a tendency to make the division between homologous and heterologous.

The first, the so-called homologous PMA, includes procedures and techniques which include the use of the gametes (spermatozoa or oocytes) of the members of the couple.

The second, the heterologous PMA, instead requires the use of oocytes or spermatozoa of external origin.

When to use the heterologous

In heterologous PMA, external donation of gametes is used, i.e. the use of a sperm donor or an oocyte donor. The first case is allowed when the male partner has proven high-grade infertility, severe ejaculatory dysfunction, genetic problems, an incurable and sexually transmitted infection, or even in cases where the male partner is Rh-positive and the female partner she is Rh-negative and severely isoimmunized.

Oocyte donation, on the other hand, is accessed in the following cases: reduced ovarian reserve after homologous fertilization failure, female hypogonadism, advanced reproductive age, genetic problems and iatrogenic infertility factor (ie caused by previous medical treatments).

A complex scenario

Although legal in Italy (a  2014 Constitutional Court ruling  dropped the ban on the use of such techniques), heterologous fertilization can encounter various obstacles, including the difficulty of finding donors, especially among women.

In fact, to avoid the trade in gametes, donations must be voluntary and free, and it is not immediate to find a donor willing to undergo hormonal treatments and treatments in the operating room to help another couple have a child.

In Italy, then, [appeals to surrogate mothers are prohibited] (
il-riconoscimento-dello-status-filiationis-del-minore-nato-mediante-pratica-di-maternita-surrogata -al-vaglio-delle-sezioni-united/), the donation of embryos, fertilization if one of the two partners is deceased, the heterologist for singles or homosexual couples.

It is an evolving scenario and a very vast field that includes not only various specificities within it, but also ramifications that impact on political, social and even ethical discourse.

Katherine Johnson, M.D., is a board-certified obstetrician-gynecologist with clinical expertise in general obstetrics and gynecology, family planning, women’s health, and gynecology.

She is affiliated with the Obstetrics and Gynecology division at an undisclosed healthcare institution and the online platform,

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