Assisted fertilization

ICSI: intracytoplasmic sperm injection

ICSI is very similar to IVF, only that in this case there is no spontaneous fertilization by one of the many spermatozoa with which the oocyte is incubated, but there is an intracytoplasmic injection of a single mature sperm of good quality inside of the oocyte

ICSI (Intracytoplasmic Sperm Injection) is a medically assisted procreation technique developed way back in 1976, but you have to wait until 1992 to see it used on humans thanks to the Italian Giampiero Palermo.

Nowadays it is the most used technique in ART, not only in cases of severe male infertility and in cases of previous IVF failures.

It is fundamentally very similar to IVF, only that in this case there is no spontaneous fertilization by one of the many spermatozoa with which the oocyte is incubated, but there is an intracytoplasmic injection of a single mature sperm of good quality inside the oocyte (subject to specific treatment).

When is ICSI used?

Indications to ICSI are

  1. Severe male infertility;
  2. obstructive and secretory azoospermia (testicular or epididymal sperm recovery)
  3. missed or reduced fertilization in previous cycles of in vitro fertilization (IVF)
  4. thawed oocytes;
  5. reduced number of oocytes;
  6. cryopreserved semen in relation to semen quality following thawing.

There is a tendency to increasingly resort to ICSI even in the absence of these indications despite the fact that there is no evidence that resorting to this technique improves fertilization rates, pregnancy rates and the percentage of children born.

How does ICSI happen?

ICSI is very similar to IVF in the first part, up to the egg pick-up . While in IVF the capacitated spermatozoa are put in contact with the oocytes, in ICSI, the spermatozoa are selected one by one. Each selected sperm is microinjected into the cytoplasm of the oocyte.

In practice , ICSI completely skips the process of natural selection which in any case occurs in IVF, such as sperm-oocyte recognition and sperm penetration into the egg cell.

The overall procedure includes:

  1.  spontaneous cycle or with induction of follicular growth and maturation of several oocytes by administering ovulation-inducing drugs;
  2. control of ovarian response to such therapy by ultrasound monitoring and/or estradiol dosage;
  3. 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 ;
  4.  possible identification of oocytes to be donated (egg sharing) for the purpose of heterologous assisted procreation ;
  5. semen sample preparation;
  6. removal of the cumulus-corona complex in oocytes;
  7. oocyte insemination by intracytoplasmic microinjection technique of a single sperm;
  8. verification of the fertilization of each oocyte;
  9. transfer of embryos to the uterus .

In the case of azoospermia, one of the following techniques is used to obtain sperm:

  • Percutaneous Testicular Sperm Aspiration (TESA),
  • Testicular sperm extraction (TESE and micro-TESE),
  • Microsurgical Epididymal Sperm Aspiration (MESA),
  • Percutaneous Epididymal Sperm Aspiration (PESA);

Before proceeding with ICSI for severe male infertility, it is essential that the couple be prescribed genetic tests and genetic counseling. It is usually required

  • male karyotype
  • genetic testing for cystic fibrosis. screening for cystic fibrosis is particularly suitable for people with azoospermia
  • test for the detection of microdeletions of the Y chromosome in selected cases characterized by azoospermia or severe oligozoospermia (< 5 million/ml)

Results

The latest annual data collected by ESHRE from European national registries (for 2016) show an increase in the cumulative use of IVF in the treatment of infertility.

Success rates after IVF or ICSI appear to have peaked, with per-treatment pregnancy rates of 27.1% after IVF and 24.3% after ICSI.

Nevertheless, according to ESHRE data, clinics in Europe continue to favor ICSI over IVF with a ratio of about two to one (359,858 ICSI and 128,626 IVF), a trend that mirrors what is happening in the rest of the world.

ICSI and congenital anomalies in children

There is currently little long-term follow-up data on the health of children born with this technique.

The study of congenital anomalies or malformations in children born thanks to assisted fertilization techniques has brought controversial results. There appears to be an increased risk of congenital anomalies in babies born with IVF compared to those conceived naturally.

It remains to be understood whether the increase in these anomalies is linked to the technique or to the altered quality of the paternal seminal fluid.

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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