How It Works: The IVF Process Step by Step

How It Works: The IVF Process Step by Step

IVF (in vitro fertilisation) bypasses the natural fertilisation process by combining egg and sperm outside the body, then returning the resulting embryo to the uterus.

Step 1 — Stimulation: The woman is given injections of FSH (and sometimes LH) to stimulate the ovaries to produce multiple eggs at once, rather than the single egg normally released each cycle. This increases the number of eggs available for collection and improves the chance of at least one successfully fertilised embryo.

Step 2 — Egg collection: Eggs are collected from the ovaries using a fine needle, guided by ultrasound. This is done under sedation.

Step 3 — Fertilisation: The collected eggs are mixed with sperm in a laboratory dish (in vitro = "in glass"). A single sperm may be injected directly into an egg (ICSI technique) if sperm motility is a problem. The fertilised eggs are observed as they divide.

Step 4 — Embryo development: Fertilised eggs develop into embryos over 2-5 days in a temperature-controlled incubator. Embryos can be screened at this stage for genetic conditions (preimplantation genetic diagnosis).

Step 5 — Implantation: One or two healthy embryos are selected and transferred into the woman's uterus. The remaining embryos may be frozen for future use, donated, or discarded — this is a key source of ethical debate.