In-vitro fertilization (IVF) is a method of assisted reproduction, in which an egg is combined with sperm outside the body. Typically, during IVF, medication is used to stimulate the ovaries to produce multiple eggs. The eggs are removed directly from the ovaries before being combined with the sperm in a laboratory environment to fertilize. The resulting embryo(s) can then be frozen or placed into the uterus in hopes of achieving pregnancy.
Considered the most powerful and effective form of assisted reproductive technology, in vitro fertilization (IVF) uses a combination of medication and surgical procedures to produce multiple eggs, help sperm fertilize an egg, and help the fertilized egg successfully implant in the uterus. IVF is often used by individuals with such issues as poor egg quality or low ovarian reserve, endometriosis, ovulation disorders, low sperm counts, or other male-factor infertility. In addition to treating infertility, IVF is also used by some individuals to prevent passing down genetic diseases.
One full cycle of IVF takes 2–3 weeks. During IVF, a patient’s ovaries are stimulated to produce multiple mature eggs, via daily injectable fertility drugs. These eggs are retrieved from the ovaries surgically.
The eggs are then fertilized by sperm in a lab by a scientist called an embryologist. The embryologist will mix the sperm and eggs in a carefully controlled lab dish (resulting in the name in vitro, which means “in glass” in Latin). Sperms surround the egg until one of them successfully penetrates its protective barrier.
The fertilized egg or eggs are then allowed to develop into blastocysts, and can be frozen or transferred to a uterus for pregnancy 3–6 days after fertilization. Alternately, blastocysts can undergo genetic screening, known as preimplantation genetic testing, to determine that they’re genetically healthy before using for pregnancy.
IVF can help with male fertility in cases of poor sperm motility, a condition in which the sperm do not swim efficiently toward the egg. During IVF, sperm and egg are mixed in a small container in the lab, so sperm do not have to travel far to reach the egg and fertilize it. Conventional IVF requires a total motile sperm count of 10,000 sperm per egg.
In cases of severe male-factor infertility, IVF paired with intracytoplasmic sperm injection (ICSI) can help. ICSI entails injecting a single sperm directly into each mature egg, and therefore facilitates fertilization even in the case of very low sperm count or motility.
Research into the possibility of IVF began as early as the late 1800s. Preliminary attempts at animal IVF began in the early 1930s, with the first mammalian IVF birth achieved in rabbits by researchers Austin and Chang in 1959.
The first IVF human birth was recorded in England in 1978. The procedure was carried out by British gynecologist Patrick Steptoe and British medical researcher Robert Edwards. While their primary aim was to bypass blocked fallopian tubes, IVF soon became an appealing reproductive technology for treating many conditions impeding fertility. Robert Edwards was awarded the Nobel Prize for Physiology or Medicine in 2010 for his work on the development of IVF.