Notes on IVF and Reproductive Medicine

Introduction to IVF

• Louise Brown: First baby born via in vitro fertilization (IVF) in 1978.
• IVF has revolutionized reproductive medicine.
• Approximately 1 in 8 heterosexual couples face difficulties in conceiving.
• High demand for IVF, also relevant for homosexual couples and single parents.
• Over 5 million babies have been born through IVF.

Natural Process of Conception

Role of the Brain

• Begins with the anterior pituitary gland releasing Follicle Stimulating Hormone (FSH) about 15 days before fertilization.
• FSH ripens ovarian follicles, leading to estrogen production.
• Each follicle contains one egg; usually, only one matures fully.

Ovulation Process

• High estrogen levels trigger a surge of Luteinizing Hormone (LH) from the anterior pituitary, causing ovulation.
• The egg is directed to the fallopian tube by fimbriae (finger-like structures).
• If unfertilized within 24 hours, the egg dies and the cycle resets.

Egg and Sperm Interaction

• Egg: Largest cell in the body, protected by zona pellucida.
• Zona pellucida prevents entry of multiple sperm.
• Sperm production takes 2-3 months; each ejaculation releases over 100 million sperm.
• Only about 100 sperm reach the egg, and only one penetrates the zona pellucida to fertilize the egg.

Development Post-Fertilization

• Zygote develops into an embryo and requires about 3 days to reach the uterus.
• Embryo takes another 3 days to implant into the endometrium.
• Implantation signals the corpus luteum to produce progesterone, maintaining pregnancy for 6-7 weeks until the placenta develops.

IVF Process

Ovarian Stimulation

• FSH levels are artificially increased to overstimulate ovaries, producing multiple eggs.
• Eggs retrieved just before natural ovulation using an ultrasound-guided needle.

Fertilization Techniques

1. Natural Fertilization: Eggs incubated with sperm in a petri dish.
2. Intracytoplasmic Sperm Injection (ICSI): A single sperm is injected directly into the egg for higher fertilization certainty.

Post-Fertilization Options

• Embryos can be screened for genetic suitability, frozen, or transferred into the uterus via catheter.
• Common to transfer embryos on day 3 (8 cells) or day 5 (blastocysts).

Use of Donor Eggs and Surrogates

• Donor eggs may be used if the mother's eggs are of poor quality.
• Gestational carriers can be used if the intended mother has a problematic uterus.

Success Rates of IVF

• Success rates can be as high as 40% for women under 35.
• Transferring multiple embryos increases chances of multiple pregnancies (twins, triplets).
• Clinics often aim to minimize the risks associated with multiple pregnancies.

Conclusion

• Millions of healthy babies have been born through IVF.
• Long-term health effects of ovarian stimulation in IVF are still being studied, but IVF appears safe.
• Advances in genetic testing and accessibility could lead to IVF outpacing natural reproduction in the future.