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How does in vitro fertilization fertilize an egg outside the body?
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infertility
Major structures and hormones involved in the initiation of pregnancy. Also seen, at right, is the development of an egg cell (ovum) from follicle to embryo.
In vitro fertilization (IVF) is a medical procedure used to treat infertility by facilitating the union of sperm and egg cells outside the human body.12
The process typically involves the following steps:
- Recovery and Preparation: Mature eggs are surgically removed from a woman's ovary, often via needle aspiration. Simultaneously, a sperm sample is collected and prepared in a laboratory.2
- Incubation: The retrieved eggs are placed in a culture medium, where the prepared sperm is added. The environment is designed to support the fertilization process.2
- Fertilization: In standard IVF, the sperm and eggs are mixed in the medium, allowing fertilization to occur naturally within 12 to 48 hours.2
- Alternative Technique: In cases of low sperm count or other fertilization difficulties, intracytoplasmic sperm injection (ICSI) may be used, where a single sperm is injected directly into the cytoplasm of an egg.23
Once fertilization is successful, the resulting embryo is observed in a growth medium before being transferred into the uterus for gestation.2