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How does in vitro fertilization help people with blocked fallopian tubes or low sperm counts?

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Diagram showing the female reproductive system with labeled ovaries, fallopian tubes, uterus, and vagina, alongside hormone pathways and the process from ovulation to fertilization and early embryo development. — 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 that bypasses natural reproductive obstacles by facilitating fertilization outside the body.12

For individuals with blocked or absent fallopian tubes, IVF is an effective solution because it removes the need for sperm and eggs to meet within the tubes. Mature eggs are retrieved directly from the woman and fertilized with sperm in a laboratory setting. Once fertilization occurs and the resulting embryo reaches a suitable stage, it is transferred directly into the uterus for gestation.12

In cases of low sperm counts, IVF can be paired with intracytoplasmic sperm injection (ICSI). During this process, a single sperm is injected directly into the cytoplasm of a retrieved egg. This technique ensures that fertilization can occur even when sperm quality or quantity is insufficient for natural conception. By managing the fertilization process in a controlled environment, these methods provide a pathway to pregnancy for couples facing these specific medical challenges.312