AQA GCSE Biology 3 Views 1 Answers
What is In Vitro Fertilisation (IVF), and what steps are involved in this procedure?
What is In Vitro Fertilisation (IVF), and what steps are involved in this procedure?
Answered step-by-step
In vitro fertilization (IVF) is a widely used assisted reproductive technology that helps individuals or couples conceive by fertilizing an egg with sperm outside the body. The process involves several key steps, each designed to optimize the chances of successful fertilization and implantation. Here’s a detailed overview of the IVF procedure:
Steps Involved in In Vitro Fertilization (IVF)
- Ovarian Stimulation:
- Purpose: The first step in IVF is to stimulate the ovaries to produce multiple eggs instead of the single egg typically released during a natural menstrual cycle.
- Medications: Patients receive hormonal medications, usually gonadotropins (FSH and LH), to promote the growth of multiple follicles in the ovaries. This phase typically lasts about 10-14 days and involves regular monitoring through blood tests and ultrasounds to assess follicle development .
- Triggering Ovulation: Once the follicles reach an appropriate size, a trigger injection (often hCG) is administered to induce final maturation of the eggs. Egg retrieval is scheduled approximately 34-36 hours after this injection .
- Egg Retrieval:
- Procedure: Egg retrieval is performed under sedation, using a transvaginal ultrasound-guided aspiration technique. A thin needle is inserted through the vaginal wall into the ovarian follicles to collect the eggs .
- Collection: The fluid from the follicles, which contains the eggs, is suctioned into test tubes and handed over to embryologists for further processing.
- Fertilization:
- Methods: The retrieved eggs are then fertilized with sperm in the laboratory. There are two primary methods:
- Standard Insemination: A specified number of motile sperm are added to a dish containing the eggs, allowing natural fertilization to occur.
- Intracytoplasmic Sperm Injection (ICSI): If sperm quality is a concern, a single sperm is directly injected into each mature egg using a fine glass needle. This method increases the chances of fertilization when sperm parameters are abnormal .
- Embryo Culture: After fertilization, the resulting embryos are cultured in a controlled environment for several days (typically 2-6 days) to monitor their development.
- Methods: The retrieved eggs are then fertilized with sperm in the laboratory. There are two primary methods:
- Embryo Transfer:
- Selection: The best-quality embryos are selected for transfer based on their development stage and morphology.
- Procedure: One or more embryos are transferred into the uterus using a soft catheter under ultrasound guidance. This procedure is generally painless and does not require anesthesia .
- Luteal Phase Support: Hormonal support (such as progesterone) may be provided after transfer to help prepare the uterine lining for implantation.
- Pregnancy Test:
- After about 10-14 days post-embryo transfer, a blood test is performed to determine if implantation has occurred and if pregnancy has been achieved.
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