D3.1.7 Use of hormones in in vitro fertilization (IVF) treatment Notes

Hormones in IVF Treatment Controls the Process of Fertilization

1. Hormones play a critical role in IVF, enabling doctors to control and optimize egg production and fertilization.

Why Are Hormones Needed in IVF?

1. In a natural menstrual cycle, a woman typically releases only one egg per month.
2. However, IVF requires multiple eggs to increase the chances of successful fertilization.
3. Hormones are used to:
   1. Suppress the natural menstrual cycle to gain control over egg production.
   2. Stimulate the ovaries to produce multiple eggs (a process called superovulation).
   3. Prepare the uterus for embryo implantation.

Steps in IVF Hormonal Treatment

1. Downregulation: Suspending the Natural Cycle

1. The first step in IVF is to suspend the woman's natural menstrual cycle.
2. This is achieved through a process called downregulation.
3. How It Works:
   1. A drug is administered (via injection or nasal spray) to suppress the pituitary gland's production of FSH and LH.
   2. This stops the secretion of oestradiol and progesterone, halting the menstrual cycle.

2. Superovulation: Stimulating Egg Production

1. Once the natural cycle is suppressed, the ovaries are stimulated to produce multiple eggs.
2. How It Works:
   1. Daily injections of FSH are given for 7 to 12 days.
   2. The goal is to achieve a higher concentration of FSH than in a normal cycle, promoting the development of multiple follicles (each containing an egg).

3. Maturation: Preparing the Eggs for Collection

1. When the follicles reach an optimal size (approximately 18 mm in diameter), they are triggered to mature.
2. How It Works:
   1. An injection of human chorionic gonadotropin (hCG) is given.
   2. hCG mimics the natural surge of LH, stimulating the final maturation of the eggs.

4. Egg Collection and Fertilization

1. Egg Collection:
   1. Eggs are retrieved from the follicles using a micropipette guided by an ultrasound scanner.
   2. This minor surgical procedure is performed 34 to 35 hours after the hCG injection.
2. Fertilization:
   1. The collected eggs are mixed with sperm in a laboratory dish and incubated at 37°C.
   2. If fertilization is successful, embryos begin to develop.

5. Embryo Transfer and Uterine Preparation

1. Embryo Transfer:
   1. One or more embryos are placed into the uterus when they are about 48 hours old.
2. Uterine Preparation:
   1. Since the woman's natural cycle has been suppressed, progesterone is administered to maintain the uterine lining and support implantation.

Why Is Superovulation Important?

1. Superovulation is a key component of IVF because it increases the number of eggs available for fertilization.
2. This improves the chances of:
   1. Successful fertilization: More eggs mean a higher likelihood that at least one will be fertilized.
   2. Viable embryos: Multiple embryos can be assessed for quality, increasing the chances of selecting a healthy one for transfer.
   3. Future attempts: Extra embryos can be frozen for use in later IVF cycles if needed.

Ethical Considerations in IVF

1. IVF raises several ethical questions, such as:
   1. Embryo selection: What should be done with unused embryos?
   2. Access to treatment: Should IVF be available to everyone, regardless of cost?
   3. Egg donation: How can we ensure the safety and fair treatment of egg donors?