The IVF Process. Step by Step
Definition
IVF Process is defined as: the complete clinical sequence of in vitro fertilization, consisting of eight stages: fertility testing, ovarian stimulation, egg retrieval, fertilization, embryo development, genetic testing (optional), embryo transfer, and pregnancy confirmation. Each stage introduces biological attrition: not every egg becomes an embryo, and not every embryo becomes a pregnancy.
IVF is often described as a treatment, but it is better understood as a sequence of medical stages. Each stage depends on the one before it. Not every egg becomes an embryo, and not every embryo becomes a pregnancy. Understanding the full process helps intended parents set realistic expectations and make informed decisions at every checkpoint.
Step 1.Fertility Testing and Diagnosis
Before IVF begins, both partners undergo diagnostic testing to identify the cause of infertility and assess ovarian reserve, sperm quality, and uterine health. Baseline blood work (FSH, AMH, estradiol) and imaging (antral follicle count, hysteroscopy) establish the clinical starting point.
Step 2.Ovarian Stimulation
Injectable FSH medications are administered for 8 to 14 days to recruit multiple follicles simultaneously. Monitoring via ultrasound and blood work every 2 to 3 days tracks follicular growth and estradiol levels. GnRH agonists or antagonists suppress premature ovulation during this phase.
Step 3.Egg Retrieval
When lead follicles reach 17 to 20 mm, a trigger shot (hCG or dual trigger) is administered. Approximately 36 hours later, eggs are retrieved through a transvaginal ultrasound-guided aspiration under sedation. Not every follicle yields a mature egg.
Step 4.Fertilization
Retrieved eggs are assessed for maturity. Mature oocytes are fertilized using conventional insemination or ICSI. Fertilization is confirmed the following morning by the presence of two pronuclei (2PN). Not all mature eggs will fertilize normally.
Step 5.Embryo Development
Fertilized eggs are cultured in specialized incubators for 5 to 6 days. Embryologists monitor cleavage, compaction, and blastocyst formation. Not all fertilized eggs reach the blastocyst stage: developmental arrest is a normal part of the attrition process.
Step 6.Genetic Testing (Optional)
If PGT is planned, a small number of cells are biopsied from the trophectoderm of each blastocyst. Embryos are vitrified while awaiting results. PGT-A screens for chromosomal number; PGT-M and PGT-SR test for specific genetic conditions or structural rearrangements.
Step 7.Embryo Transfer
A selected embryo is transferred to the uterus using a thin catheter guided by ultrasound. The transfer can be a fresh transfer (same cycle as retrieval) or a frozen embryo transfer (FET) in a subsequent cycle. Progesterone supplementation supports the endometrial lining.
Step 8.Pregnancy Test
Approximately 9 to 14 days after embryo transfer, a blood test measures beta-hCG to determine whether implantation has occurred. A positive result leads to ongoing monitoring. A negative result initiates a clinical review before any subsequent cycle.
Understanding Attrition
At every stage of IVF, biological attrition reduces the number of potential outcomes. Not every follicle contains a mature egg. Not every egg fertilizes. Not every fertilized egg reaches blastocyst. Not every blastocyst is chromosomally normal. And not every transferred embryo implants. This is not a failure of IVF: it is a reflection of human reproductive biology that IVF makes visible but cannot override.
Knowledge Graph
Related reference pages and tools in this system.
Legal and Governance
Sources
- Society for Assisted Reproductive Technology (SART) national reports, https://www.sart.org
- Human Fertilisation and Embryology Authority (HFEA) statistics, https://www.hfea.gov.uk
- European Society of Human Reproduction and Embryology (ESHRE), https://www.eshre.eu