What is the IVF (In Vitro Fertilization) process?

In Vitro Fertilization (IVF) Process

In vitro fertilization (IVF) is an established assisted reproductive technology that allows fertility for couples where natural pregnancy has not previously occurred, involving the fertilization of eggs outside the body followed by embryo transfer into the uterus. 1, 2

Overview of the IVF Process

• IVF involves retrieving oocytes (eggs), fertilizing them outside the body, growing embryos in a laboratory environment, and subsequently transferring them into the woman's uterus 2
• The procedure has resulted in thousands of successful pregnancies since the first IVF baby was born in 1978 3
• Success rates have steadily improved over decades due to advances in laboratory procedures and technology 2

Key Stages of IVF Treatment

1. Ovarian Stimulation

• Controlled ovarian hyperstimulation is used to produce multiple oocytes, which improves pregnancy rates by increasing the number of high-quality embryos available for transfer 3

• Common stimulation agents include:

  • Gonadotropins such as human menopausal gonadotropin (hMG/menotropins) 3
  • Follicle-stimulating hormone (FSH) analogs, including recombinant human FSH 3, 4
  • GnRH agonists or antagonists to prevent premature ovulation 4

• Personalized stimulation protocols are designed based on the woman's age and ovarian reserve to maximize the efficacy of the IVF process 5

2. Monitoring Follicular Development

• Serial ultrasounds and blood tests are performed to monitor follicular growth and hormone levels 4
• This monitoring ensures proper timing of the ovulation trigger 4

3. Ovulation Trigger

• Human chorionic gonadotropin (hCG) or GnRH agonists are administered to trigger final oocyte maturation before retrieval 3
• Timing is critical to ensure oocytes are at the optimal stage of development 3

4. Oocyte Retrieval

• Eggs are collected via transvaginal ultrasound-guided needle aspiration 2
• The procedure is typically performed under conscious sedation with medications such as midazolam, pethidine, or fentanyl 3

5. Fertilization

• Retrieved eggs are fertilized in the laboratory using either:
  • Conventional IVF: Eggs and sperm are placed together in a culture dish 2
  • Intracytoplasmic Sperm Injection (ICSI): A single sperm is directly injected into each mature egg, particularly useful for male factor infertility 2, 1

6. Embryo Culture

• Fertilized eggs are cultured in the laboratory for 3-5 days as they develop into embryos 2
• Embryo quality is assessed based on morphological criteria and development rate 2

7. Embryo Transfer

• Selected embryos are transferred into the woman's uterus using a thin catheter 2
• The number of embryos transferred is carefully considered to balance pregnancy success rates against the risk of multiple pregnancies 1
• Progesterone supplementation is generally used in the luteal phase of the IVF cycle to support implantation 3

8. Cryopreservation

• Extra high-quality embryos can be cryopreserved (frozen) for future use 2
• This allows for additional transfer attempts without requiring another ovarian stimulation cycle 1

Special Considerations

• For men with infertility, IVF with ICSI can overcome many male factor issues as long as adequate viable sperm are present 1
• Men interested in current or future fertility should avoid testosterone monotherapy as it can suppress spermatogenesis 1
• For women with reduced ovarian reserve or advanced maternal age, modified protocols such as DuoStim (double stimulation in the same ovarian cycle) may be considered to improve oocyte yield 5
• Embryo cryopreservation after IVF has been highly successful in women younger than 40 years of age 1
• Mature oocyte cryopreservation is an alternative for single women but, like embryo cryopreservation, requires hormone stimulation 1

Success Rates and Outcomes

• IVF success rates vary based on multiple factors including:
  • Woman's age
  • Cause of infertility
  • Quality and number of embryos transferred 1
• Live birth is considered the most important outcome measure in IVF treatments 1
• Men with low total motile sperm count (<5 million motile sperm after processing) will have limited chances of contributing to pregnancy rates after intrauterine insemination (IUI), making IVF with ICSI a more appropriate option 1

Alternative Approaches

• For patients with specific fertility challenges, variations of the standard IVF protocol may include:
  • In vitro maturation (IVM) of immature oocytes 1
  • Use of donor eggs, sperm, or embryos 1
  • Gestational carriers when indicated 1

Fertility Preservation Considerations

• IVF techniques are also used for fertility preservation before cancer treatments or for other medical indications 1
• Options include embryo cryopreservation, oocyte cryopreservation, and ovarian tissue cryopreservation 1
• These procedures should ideally be performed before the start of treatments that may affect fertility 1