Which sequence correctly lists the steps of in vitro fertilization (IVF)?

• A. Ovarian stimulation; Egg retrieval; Insemination/Fertilization; Embryo Transfer; Embryo culture
• B. Ovarian stimulation; Embryo culture; Egg retrieval; Insemination; Embryo transfer
• C. Ovarian stimulation; Egg retrieval; Insemination/Fertilization; Embryo culture; Embryo transfer
• D. Egg retrieval; Ovarian stimulation; Embryo culture; Insemination/Fertilization; Embryo transfer

Answer: (C)

IVF follows a strict workflow where each step depends on the one before it. You start by stimulating the ovaries to produce multiple eggs, then retrieve those eggs from the ovaries. After retrieval, the eggs are fertilized in the lab with sperm, and the resulting embryos are allowed to develop in culture. Finally, one or more healthy embryos are transferred into the uterus.

This order is best because you can’t fertilize eggs you haven’t retrieved, you can’t culture embryos before they are fertilized, and you can’t transfer embryos until they have developed in culture. The other sequences mix up these dependencies—placing culture before retrieval, or transfer before culture, or retrieving eggs before stimulation—so they don’t reflect how IVF actually progresses.