treatments
Fertilização in vitro (FIV/ICSI)
In vitro fertilization consists of the fertilization of an oocyte by a sperm, in a laboratory (outside the woman's body), in order to obtain embryos that will later be transferred (usually 1 or 2) to the uterus in the hope of obtaining a pregnancy.
In in vitro fertilization, gametes (sperm and oocytes) from both members of the couple can be used, or gametes can be donated.
Fertilization of oocytes can be achieved using two different laboratory techniques, IVF (in vitro fertilization) and ICSI (intracytoplasmic sperm microinjection).
IVF consists of the joining of oocytes with sperm in an appropriate culture medium for fertilization to occur. It is the technique of choice in cases of tubal obstruction, some cases of endometriosis and in cases of mild male factor.
ICSI consists of injecting a single sperm into the oocyte. It is indicated in cases of infertility due to severe male factor, fertilization failures in previous IVF and in cases of poor egg quality.
In addition to treatments in the context of infertility, in vitro fertilization (IVF/ICSI) can also be used in other contexts:
- Treatments for female couples (reciprocal fertilization or shared motherhood - ROPA): a woman receives embryos created from her partner's oocytes and sperm donation);
- Treatments for women without a partner: embryos created from the woman's own or donor's oocytes and sperm donation.
In IVF/ICSI treatments, the average pregnancy rate is around 35 to 40%. The woman's age is the factor that most influences the success rate, which can be greater than 40% in women with a good prognosis (less than 35 years old), while in women over 42 years old, with their oocytes, the probability is around 10%.
Indications
- Previous failure in ovulation induction treatments or IUI;
- Situations of tube obstruction;
- Moderate (IVF) to severe male factor (ICSI);
- Endometriosis;
- Treatments using pre-implantation genetic testing (PGT);
- Treatments using egg donation.
Procedure
Ovarian Stimulation
To increase the success of an IVF/ICSI cycle, it is necessary to stimulate the ovaries so that they produce a significant number of oocytes. Stimulation is carried out using daily administration of injectable hormonal medication (gonadotropins) that allows the growth of several follicles simultaneously.
The dose of hormonal medication varies according to the clinical situation and response of the ovaries, hence the importance of a personalized approach to treatment, with constant medical monitoring.
The response of the ovaries (number and size of growing follicles) is monitored through ultrasound at intervals of approximately 3 days.
When a reasonable number of follicles reach the pre-ovulatory state (dimensions greater than 18 mm on an ultrasound image), ovulation is triggered through the administration of another injectable hormonal medication.
Follicular Puncture
Follicular puncture is a quick surgical procedure that allows aspiration of follicles (containing oocytes). It is performed under brief general anaesthesia, vaginally, through a needle attached to the probe, usually approximately 35 hours after ovulation triggering.
The aspirated follicular fluid is immediately taken to the laboratory for examination under a microscope and identification and collection of oocytes.
After a recovery period, the patient can resume normal life.
Depending on the defined treatment, additional medication may be prescribed to promote uterine receptivity for fresh embryo transfer.
Laboratory Procedure
Fertilization
In the case of IVF, previously treated sperm are placed together with the oocytes for fertilization to occur.
In the case of ICSI, before proceeding with microinjection, it is necessary to denude the oocytes. This process consists of removing all the cells surrounding the oocyte in order to assess its maturity and quality. Only mature oocytes can be subjected to microinjection, as they are the only ones capable of fertilization.
Microinjection consists of injecting a sperm into an oocyte with the help of two micropipettes, one to hold the oocyte and the other to introduce the sperm into the cytoplasm.
Processing of oocytes and sperm
In the embryology laboratory, the follicular fluid is observed under a magnifying glass in order to find the oocytes, which are placed in an appropriate culture media and maintained in an incubator, in a controlled environment.
In an intramarital cycle, after collecting the oocytes, it is necessary to collect the ejaculate sample. The collection is carried out, preferably, on the clinic premises, by masturbation and after a period of abstinence of two days. In exceptional cases, the collection can be carried out outside the CEIE facilities, as long as it is delivered by the person and upon signature of a document for this purpose.
The ejaculate sample is processed according to specific protocols in order to select sperm based on specific parameters such as concentration, motility and morphology.
In other situations, the sample used may come from sperm donation.
Fertilization Assessment and Embryo Culture
The day after IVF/ICSI, fertilization is assessed by observing two nuclei, the male and the female.
In the following hours, the process of cell division begins, which continues for the following days. The embryos are maintained in culture in the incubator and their development (several cell divisions) is monitored using time-lapse technology.
Embryo Transfer
Three to five days after collecting the oocytes, the selected embryo(s) is transferred.
Transfer is a simple procedure in which an embryo is placed in the uterine cavity with the help of a flexible catheter that is introduced through the cervix. In some cases, based on clinical indication, two embryos may be transferred.
After the transfer, the woman resumes her normal life. Twelve days after the transfer, through a blood test, it is possible to know if you are pregnant, by measuring a hormone, beta-hCG, the pregnancy hormone. Twenty-one days later, it is now possible to confirm the pregnancy by ultrasound, confirming the clinical pregnancy.
Embryo Cryopreservation
In IVF/ICSI cycles, embryo cryopreservation can be carried out using the vitrification technique for different reasons:
- Existence of a higher number of good quality embryos than those transferred (supernumerary embryos).
- Impossibility of transferring due to ovarian hyperstimulation syndrome, endometrial inadequacy, or other reason.
- Prior decision to carry out a cycle with total cryopreservation of the embryos (called freeze-all cycle).
In the last two cases, the embryo transfer is delayed from the fresh cycle, taking place later, after preparing the endometrium with an appropriate protocol and thawing the embryo(s).
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