What is in vitro fertilisation (IVF)?

Fertilisation outside the body.

The correct answer is Option (3) – Fertilisation outside the body.

In vitro fertilization (IVF) is a fertility treatment where fertilization occurs outside the body, typically in a laboratory setting.

Fertilization inside the body: This refers to natural fertilization, which happens inside a woman's body when sperm from a male partner meets an egg in the woman's fallopian tube or uterus.

Embryo formation without fertilization: This statement doesn’t align with the natural biological process. Embryo formation typically occurs after fertilization, where a sperm cell penetrates an egg, leading to the formation of an embryo.

Fertilisation outside the body: This is the correct description of IVF. It involves combining eggs and sperm outside the body in a laboratory dish ("in vitro"), allowing fertilization to occur. Once fertilization occurs and embryos develop, they are then transferred to the woman's uterus to establish a pregnancy.

Prevention of fertilisation: This refers to methods or interventions aimed at preventing the union of sperm and egg, hence preventing fertilization. Contraceptive methods like condoms, birth control pills, intrauterine devices (IUDs), and certain emergency contraception pills work by preventing fertilization.

IVF, on the other hand, facilitates fertilization by bringing eggs and sperm together outside the body in a controlled environment, offering hope to individuals or couples facing infertility issues. It's a multi-step process involving hormone stimulation, egg retrieval, fertilization in a laboratory setting, embryo culture, and embryo transfer into the uterus for potential implantation and pregnancy.