ICSI – Intracytoplasmic sperm injection (test tube insemination by means of sperm microinjection)
Conventional IVF and ICSI
The base therapy for ICSI is IVF. The only difference from IVF is that in the case of ICSI, rather than introducing 100,000 sperm cells to each egg cell, only a single sperm is injected into the egg cell. In the text that follows, the ONLY difference from IVF is highlighted in a different colour. The remainder of the text is identical!
1. Initial treatment with medications
In conventional IVF, initial treatment with medications is used to create the optimal hormonal conditions and to generate a relatively high number of egg cells. For this purpose, patients are usually given daily subcutaneous injections of 150 -225 IU of FSH (Gonal-F or Puregon) or a FSH/LH mixture (Menogon). Various additional medications will be required to prevent premature ovulation (Synarel spray, Zoladex, Enantone, Decapeptyl).
If enough follicles (egg vesicles) have grown, the so-called “ovulation injection” (Brevactid, Pregnesin, Ovitrelle) is administered to end the egg cell maturation phase. With the help of follicular aspiration, multiple egg cells are now retrieved.
2. Egg retrieval
Ultrasound-guided transvaginal follicular aspiration (puncture) generally requires the patient to be under anaesthesia for a short amount of time. This procedure takes place 32 to 36 hours after the hCG injection.
This involves advancing the aspiration needle with an ultrasound transducer through the vaginal wall to the ovary. There, one follice (egg vesicle) after another is aspirated. The liquid is drawn out and passed directly to the biologist so that it can be determined immediately whether the follicle contains an egg cell.
In the laboratory, a complex microscope is used to inject a single sperm into each egg cell. The dishes are incubated (cultured) in an incubation cabinet overnight.
… a glass capillary is then used to inject the sperm directly into the egg cell.
After it has been determined 19 – 21 hours later how many cells have reached what is known as the pronucleus (PN) stage, a maximum of 3 PN-stage cells (this is the case in Germany, at least) must be selected to complete the fertilisation process. The pronuclei each contain the chromosomes of the egg cell and the sperm cell.
On day 2 or 3 after the sperm has been introduced, when one or more embryos have developed, the embryo(s) are transferred into the uterine cavity. A transfer on day 5 is also possible and is advisable if one or more blastocysts have developed at that time.
Click here for more information on blastocyst transfer
4. Embryo transfer
Embryo transfer is performed on day 2, 3 or 5 after the sperm has been introduced. This is an entirely pain-free procedure during which a catheter is advanced into the uterine cavity, if necessary with ultrasound guidance. The embryo(s) are carefully positioned there. To prepare for the transfer, the woman can take medications to relax the muscles in the womb. Over the next 14 days, progesterone (luteinising hormone: Crinone-Gel, Utrogest) should be added to achieve optimal conditions in the mucous lining for implantation (nidation) of the embryo.
During the time following embryo transfer, patients should avoid excitement and excessive activity. They should also avoid cardiovascular exertion such as sports and severe increases in temperature (such as saunas or hot baths). Otherwise, there are no specific recommendations. Even sex is more likely to have a positive effect.
12 to 14 days after fertilisation, a urine pregnancy test or a blood test can be performed to determine whether the woman is pregnant.