Final answer:
IVF is a procedure where an egg and sperm are fertilized outside the body in a lab, and the embryo is then transferred to the uterus.
Step-by-step explanation:
In vitro fertilization (IVF) refers to a procedure where fertilization of an egg by a sperm takes place outside the body, in a laboratory setting. Specifically, IVF involves collecting mature eggs from the ovaries after extensive hormonal treatment, combining them with sperm in a Petri dish, and supporting their development through several cell divisions. Once the embryos reach the eight-cell stage, one or more are implanted into the woman's uterus for potential pregnancy. Conditions warranting the use of IVF include blocked fallopian tubes, low sperm counts, and other infertility issues that prevent natural conception. If IVF does not result in fertilization, a specialized procedure called intracytoplasmic sperm injection (ICSI) may be used, where a single sperm is directly injected into an egg.