Table of Contents
- After the egg retrieval process during in vitro fertilization (IVF), the real magic begins in the embryology lab. This is where the complex and delicate work of fertilizing the eggs and monitoring their development takes place. Understanding what happens behind the scenes can help you feel more informed and confident throughout your IVF journey. Here's a detailed look at the steps that take place after your eggs are retrieved.
- 1. Identification of Eggs
- 2. Sperm Collection and Preparation
- 3. ICSI: Fertilization by Direct Sperm Injection
- 4. Fertilization: Watching for Early Signs of Life
- Why Some Eggs Don’t Fertilize
- 5. Continuous Monitoring of the Developing Embryo
- 6. Assisted Hatching: Giving the Embryo a Helping Hand
- 7. Blastocyst Biopsy for Preimplantation Genetic Testing (PGT)
- The Final Step: Embryo Transfer or Freezing
- Comprehensive IVF Care at Sama
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After the egg retrieval process during in vitro fertilization (IVF), the real magic begins in the embryology lab. This is where the complex and delicate work of fertilizing the eggs and monitoring their development takes place. Understanding what happens behind the scenes can help you feel more informed and confident throughout your IVF journey. Here's a detailed look at the steps that take place after your eggs are retrieved.
1. Identification of Eggs
Once your eggs are retrieved during a minor surgical procedure, they are immediately handed over to the embryology team. The first task is to carefully identify and examine the eggs under a microscope. The retrieved fluid from the follicles is inspected to find and isolate the mature eggs, as only mature eggs are capable of being fertilized. Eggs are categorized based on their maturity, and immature eggs may be cultured for a short period to allow for further maturation.
2. Sperm Collection and Preparation
While your eggs are being prepared, your partner (or donor) provides a sperm sample, which is carefully processed in the lab. The healthiest, most motile sperm are selected using specialized techniques to ensure the highest quality sperm are available for fertilization. In cases of male factor infertility, or when sperm are collected through surgical procedures, ICSI (intracytoplasmic sperm injection) is often used.
3. ICSI: Fertilization by Direct Sperm Injection
In most cases at Sama, eggs are fertilized using intracytoplasmic sperm injection (ICSI). ICSI involves injecting a single, high-quality sperm directly into the center of the egg using a tiny, specialized needle. This technique is essential for overcoming fertilization challenges such as low sperm count, poor sperm motility, or prior failed attempts at fertilization.
If conventional fertilization is used, sperm are introduced into the same dish as the egg, allowing fertilization to occur naturally. This process mimics what happens in the body, but ICSI is typically preferred for its increased success rate.
Read more about ICSI at Sama.
4. Fertilization: Watching for Early Signs of Life
Once fertilization occurs, the eggs are monitored for the first signs of development, which happen within the first 16-20 hours. Successful fertilization is indicated by the appearance of two pronuclei—one from the sperm and one from the egg. These early fertilization markers show that the genetic material from both parents is combining, setting the stage for embryo development.
Why Some Eggs Don’t Fertilize
It’s important to remember that not all eggs will fertilize, even with ICSI. There are several reasons for this:
- Egg Immaturity: Sometimes, even if an egg looks mature, it may still be incomplete in terms of its ability to fuse with the sperm’s DNA.
- Sperm Quality: While ICSI can overcome many male factor infertility issues, if the sperm’s DNA is damaged or if there are underlying genetic issues, fertilization may fail.
- Egg Quality: The quality of the egg is also crucial. Poor egg quality due to age, ovarian health, or other factors may result in unsuccessful fertilization, even if the sperm is healthy.
5. Continuous Monitoring of the Developing Embryo
After fertilization, embryos are carefully monitored as they grow and divide. This development occurs over the course of 5-6 days in the lab, where embryologists check on the embryos daily. Some of the stages of monitoring include:
- Cleavage Stage (Days 1-3): The fertilized egg divides into two cells, then four, then eight, as it moves through early cell divisions.
- Blastocyst Stage (Days 4-5): By day 5 or 6, the embryo reaches the blastocyst stage, a key point where the embryo begins to differentiate into the cells that will form the fetus and the placenta. A blastocyst contains hundreds of cells and has a high chance of implantation during an embryo transfer.
Sama embryologists use time-lapse imaging technology to monitor embryos continuously without disturbing their development. This allows for precise tracking of growth and the ability to select the most viable embryos for transfer.
6. Assisted Hatching: Giving the Embryo a Helping Hand
In some cases, the embryo's outer shell, called the zona pellucida, may be too thick, which can prevent it from properly hatching and implanting into the uterine lining. Assisted hatching involves making a small incision in the zona pellucida to help the embryo hatch, increasing the chances of implantation. Assisted hatching is especially helpful for patients with previous failed IVF cycles, women over 35, or those with thick zona pellucida.
Read more about Assisted Hatching at Sama.
7. Blastocyst Biopsy for Preimplantation Genetic Testing (PGT)
For patients undergoing preimplantation genetic testing (PGT), a small sample of cells from the outer layer of the blastocyst is biopsied and sent for genetic analysis. This biopsy doesn’t harm the embryo and provides valuable information about its chromosomal health. PGT can screen for aneuploidy (abnormal number of chromosomes), as well as specific genetic disorders, helping to select the healthiest embryos for transfer.
By identifying chromosomally normal embryos, PGT can increase the chances of a successful pregnancy and reduce the risk of miscarriage. For patients with recurrent pregnancy loss, advanced maternal age, or a family history of genetic disorders, PGT offers an added level of assurance.
The Final Step: Embryo Transfer or Freezing
After the embryos are monitored and tested, a decision is made about which embryo(s) to transfer. The healthiest embryo(s) are selected for embryo transfer, while the remaining viable embryos can be frozen for future use through cryopreservation. This allows patients to have additional chances at pregnancy without undergoing another IVF stimulation cycle.
Comprehensive IVF Care at Sama
At Sama, our embryology lab uses the latest technology and techniques to ensure the highest chances of success. From ICSI and continuous embryo monitoring to assisted hatching and PGT, our lab is equipped to handle every step of your IVF journey with precision and care.
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