In vitro fertilization
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 fertilized egg (zygote) undergoes embryo culture for 2–6 days, it is implanted in the same or another woman’s uterus, in those cases where the woman’s natural uterus is absent or otherwise unsuitable.
IVF is a type of assisted reproductive technology used for infertility treatment and gestational surrogacy. A fertilized egg may be implanted into either a surrogate’s uterus, or transferred to the uterus of the woman who provided the eggs.
Some countries have been using this method to create “designer babies”, where the selection of genetic traits are controlled.
In IVF, after stimulation of the ovaries, eggs are retrieved through a minor surgical procedure. They are then fertilized by sperm in a lab, and the resulting embryos are cultured for three to five days until they reach the proper stage for implantation into the uterus.
IVF is a major cause of multiple births in developed countries. Due to the costs and risks associated with multiple births, many IVF babies are now delivered as singletons.
When implantation is successful, pregnancy begins. If implantation is unsuccessful, the egg and sperm are usually washed away and the process begins anew. If the IVF process results in the birth of multiple babies, as is often the case, those babies are usually delivered by Caesarean section.
IVF is usually performed as a cycle, with one egg retrieval and one embryo transfer per cycle. The average success rate for each cycle is about 30%.