In vitro fertilization is an assisted fertilization technique based on the surgical removal of mature oocytes (pick-up) and fertilization in the laboratory with the partner’s sperm. The first IVF in history was obtained in 1978 and since then about 2 million babies have been born with this technique.
When is in vitro fertilization used?
It is recommended for severe endometriosis, severe tubal diseases such as obstruction, moderate male fertility problems, IUI failure and unexplained infertility.
In particular, IVF (or ICSI) is necessary to achieve pregnancy in case of:
- tubal-peritoneal factor: acquired or congenital tubal pathology (previous ectopic pregnancy, previous tubal abortions, history of pelvic inflammation, surgery on the pelvis);
- moderate male infertility: when medical and surgical treatment or intrauterine inseminations have failed or have been judged inappropriate;
- endometriosis of III or IV degree;
- endometriosis if surgery or intrauterine inseminations have failed or have been judged inappropriate;
- unexplained infertility if previous treatment (eg, insemination cycles) failed or was judged inappropriate;
- cryopreserved semen in relation to semen quality after thawing;
- failure of the low-tech therapeutic process.
3 different types of protocols are mostly used in this technique:
- On a natural cycle
- long protocol: cycle with GnRH agonist
- short protocol: cycle with GnRH antagonist
The procedure will include:
- in a spontaneous cycle or with induction of follicular growth and maturation of several oocytes through the administration of drugs that induce ovulation;
- control of the ovarian response to such therapy by ultrasound monitoring and / or estradiol dosage;
- transvaginal oocyte retrieval, under ultrasound control, under local anesthesia and / or deep sedation, or laparoscopic or transabdominal retrieval in cases where the trans-vaginal technique is not applicable
- possible identification of the oocytes to be donated (egg sharing) for the purposes of assisted procreation of the heterologous type;
- preparation of the semen sample;
- choice of oocytes;
- union and extracorporeal culture of gametes (oocytes and spermatozoa);
- verification of the successful fertilization of each oocyte;
- transfer of embryos to the uterus.
THE long protocols they are the most commonly used. It involves the administration of a GnRH agonist. The purpose of prolonged administration is to achieve the absence of ovarian stimulation and the suppression of folliculogenesis. In about 3 weeks, estradiol levels are similar to those of menopause.
Once ovarian suppression has been verified, ovarian stimulation with gonadotropins can be performed.
THE protocols with antagonists are recently introduced. The advantage is that their action on the pituitary is practically immediate, protecting the patient from having a premature LH surge and therefore spontaneous ovulation. The advantages of this short protocol are the absence of side effects (similar to menupausals), no risk of cysts, shorter duration of stimulation, lower total gonodatropin dosage per cycle and therefore cost savings.
As in the IUI it is important to constantly monitor follicular growth during stimulation, via transvaginal ultrasound. Scheduled estradiol assays can also be used to add information to ultrasound monitoring.
Egg retrieval (pick-up)
To achieve the final maturation of the oocyte, hCG is administered. This administration should be done when one or two dominant follicles with a diameter equal to or greater than 17 millimeters are reached. Usually the administration takes place about 34 hours before egg retrieval.
The sampling is carried out with modern techniques, through ultrasound-guided transvaginal probes.
The collection is usually done under local anesthesia and takes 20 to 30 minutes depending on the number of oocytes to be collected. Patients are usually discharged a few hours after the procedure.
The embryo transfer:
The collected oocytes are fertilized in the laboratory
In a standard in vitro fertilization the oocytes are incubated with a concentration of motile spermatozoa equal to 100000 / ml. Otherwise, proceed for an ICSI.
Incubation must take place under specific conditions of temperature, PH and gas content.
Incubation leads to the formation of embryos that must be transferred to the uterus. To the second day they are in the 4 cell stage, on the third day they are in the 8 cell stage, on the third day they are in the morula stage and on the fifth day they are in the blastocyst stage.
The embryo transfer takes place either on the third day after oocyte retrieval or on the fifth day at the stage of blastocyst. The advantage of the transfer on the fifth day is that the embryo is placed in the uterus in a phase in which it would physiologically be there. The transfer of the blastocyst also also allows better selection of embryos as between the 2nd and 5th day the abnormal ones stop their development.
The transfer is performed without anesthesia using a special catheter.
When can you take the pregnancy test?
It is recommended to do it no earlier than 12 days after the embryo transfer. If the test is positive, an ultrasound scan is performed after 2-3 weeks to assess the state of pregnancy. If the blood beta is measured, if the beta hCG value is low, it must be repeated 48 hours later to evaluate its progress.
The success of this technique depends a lot on the woman’s age (the more the woman’s age increases, the lower the chances of success) and on the cause of infertility. Smoking and obesity are also parameters that undermine the success of IVF. Obviously the role of the laboratory is crucial.
The latest annual data collected by ESHRE from European national registries (for 2016) success rates after IVF or ICSI appear to have reached a peak, with pregnancy rates per treatment initiated of 27.1% after IVF and at 24.3% after ICSI.
From the Italian PMA register:
Table 4.28 shows the pregnancy percentages according to the age groups of the patients with respect to the cycles started, the samples taken and the transfers performed only for fresh IVF and ICSI techniques.
What are the complications associated with in vitro fertilization?
As with any medical procedure, there are risks which mainly include:
- multiple pregnancies (the incidence decreases by transferring a single embryo at a time)
- low birth weight and premature birth
- ectopic pregnancy
- ovarian hyperstimulation syndrome (OHSS), a rare condition involving excess fluid in the abdomen and chest
The decision to undergo any assisted fertilization treatment, whatever it is, is very important because it requires physical, emotional and even economic commitment.
Always discuss with your doctor not only the best options available, but also whether assisted fertilization is the right path for you. A support group and / or a psychotherapist who specializes in couple infertility can also be of great help throughout the process.
ACTIVITIES OF THE ITALIAN NATIONAL REGISTER OF MEDICALLY ASSISTED REPRODUCTION
GUIDELINES CONTAINING THE INDICATIONS OF MEDICALLY ASSISTED PROCEDURES AND TECHNIQUES Art. 7 – Law no. 40/2004 2015 GUIDELINES
Bibliography: DeWURST et all. Treatise on gynecology and obstetrics