The ICSI treatment procedure can be clearly understood with the following points.
1. Ovarian Stimulation (Ovulation Induction)
The ICSI cycle begins with ovarian stimulation, also known as ovulation induction. This phase involves self-administered daily injections of follicle-stimulating hormone (FSH), usually starting on Day 2 or 3 of the menstrual cycle.
The goal is to encourage the ovaries to develop multiple follicles, each potentially containing a mature egg. Ovarian stimulation generally lasts between eight and 14 days, depending on how the ovaries respond.
2. Control and Monitoring
Throughout ovarian stimulation, the fertility specialist closely monitors follicle development using ultrasound scans and/or blood tests. This careful observation helps the team track the number and size of growing follicles. Based on these results, medication dosages may be adjusted to optimize the response and reduce risks such as overstimulation.
3. Egg Release (The Trigger Injection)
When the follicles reach the appropriate size, a final injection commonly called the “trigger injection” is administered. This medication, typically hCG or Lupron, supports the final maturation of the eggs and helps loosen them from the follicle walls. Timing is essential, as this prepares the eggs for retrieval.
4. Egg Retrieval
Egg retrieval is scheduled approximately 36 hours after the trigger shot. This short procedure is performed under light sedation or mild anesthesia for comfort.
Using transvaginal ultrasound guidance, a thin needle is passed through the vaginal wall into the ovaries. A suction device then collects the follicular fluid containing the eggs. It is important to note that not every follicle will contain a mature egg.
5. Sperm Collection and Preparation
Sperm is usually collected on the same day as egg retrieval, unless previously frozen sperm is being used. The individual providing the sample is advised to abstain from ejaculation for two to three days beforehand. Once collected, the sample must reach the laboratory within 60 minutes.
A semen analysis is performed immediately to evaluate sperm count, motility, and morphology. In cases where no sperm are present in the ejaculate or ejaculation is not possible, surgical retrieval methods such as Microsurgical Testicular Epididymal Sperm Extraction (micro TESE) may be used.
6. Insemination via ICSI
The defining feature of ICSI is the injection of a single, carefully selected sperm directly into each mature egg. The embryologist selects a sperm with a normal appearance and suitable movement.
The egg is held steady with a pipette while a fine needle introduces the sperm into its cytoplasm. The needle is then withdrawn, and this process is repeated for all mature eggs.
7. Fertilization and Embryo Culture
Injected eggs are placed in an incubator, and fertilization is checked 16-18 hours later. Normally, fertilized eggs continue to develop over the next 5 days, ideally reaching the blastocyst stage by Day 5 or 6. Not all eggs will fertilize, and not all embryos will progress to this stage.
8. Embryo Transfer and Vitrification
On Day 5, embryos are assessed for quality, and the best embryo is selected for transfer into the uterus using a thin catheter. This quick, generally painless procedure usually involves transferring a single embryo, unless otherwise planned. Embryos of sufficient quality that are not transferred are vitrified through Embryo Freezing for future use, with high survival rates upon thawing.
9. Pregnancy Test
The cycle concludes with the two-week luteal phase following embryo transfer. A blood test is then performed to confirm pregnancy, marking the final step of the ICSI process.
Read More: Tests Prior to IVF – ICSI