In-vitro fertilization (IVF) is a process of fertilization where an egg is combined with sperm outside the body, in vitro (“in glass”). The process involves monitoring and stimulating a woman’s ovulatory process, removing an ovum or ova (egg or eggs) from the woman’s ovaries and letting sperm fertilize them in a liquid in a laboratory. After the fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is implanted in the same or another woman’s uterus, with the intention of establishing a successful pregnancy.
IVF as a treatment for infertility
IVF is a major treatment in infertility when other methods of assisted reproductive technology have failed. The process may be used to overcome female infertility when it is due to problems with the fallopian tubes, making direct fertilisation in vivo impossible. It can also assist in male infertility, in those cases where there is a defect in sperm quality; in such situations intracytoplasmic sperm injection (ICSI) may be used, where a sperm cell is injected directly into the egg cell. This is used when sperm has difficulty penetrating the egg.
IVF success rates
The success of IVF depends on a number of factors. These include the cause of infertility, the age of the woman, the number of eggs retrieved, sperm quality, and the number of embryos transferred.
Age is the most significant factor affecting the chance of having a baby. The chance of a live birth decreases rapidly after age 35. Also, as women get older, they are more likely to have miscarriages or babies with birth defects.
The cause of infertility also affects the chances of having a baby. For example, if a woman has blocked fallopian tubes, the chance of a live birth is about 35%. If a man has a low sperm count, the chance of a live birth is about 10%.
The number of eggs retrieved also affects the chances of a live birth. The more eggs that are retrieved, the more likely it is that one of them will be fertilized and grow into a baby.
The quality of the sperm also affects the chances of a live birth. If the sperm are of poor quality, they are less likely to fertilize the eggs.
The number of embryos that are transferred also affects the chances of a live birth. The more embryos that are transferred, the more likely it is that one of them will implant in the uterus and grow into a baby.
The chance of a live birth with IVF also depends on the IVF center where the treatment is done. IVF success rates vary from center to center and from year to year.