What's the Difference Between IVF and IUI?

“Intrauterine insemination (IUI) and in vitro fertilization (IVF) are two commonly used methods to increase the chance of pregnancy,” says Aaron K. Styer, M.D., reproductive endocrinologist and co-medical director of CCRM Boston. But the similarities pretty much end there.

Often referred to as “artificial insemination,” IUI is a procedure during which processed and concentrated motile sperm (think: the best and fastest swimmers) are inserted directly into a woman’s uterus, Dr. Styer explains. It’s timed according to a woman’s ovulation since, after that, her egg—or eggs—are picked up by the fallopian tube, where they then sit and wait for the sperm.

“Because IUI deposits higher concentrations of good quality sperm close to where the egg is waiting, the chance that the egg and sperm will find one another is increased,” Dr. Styer says.

The IVF process, meanwhile, includes stimulation of the ovaries to produce multiple eggs at a time, removal of the eggs from the ovary (a.k.a., egg retrieval), fertilization of the eggs in the laboratory, and subsequent placement of the resulting embryos into the uterus (a.k.a., embryo transfer).

The chance of pregnancy from IVF primarily depends on the woman’s age, the cause of infertility, and the quality of the IVF laboratory. The Society for Assisted Reproductive Technology (SART) publishes all fertility clinics’ IVF success rates and also has a handy online tool that offers a prediction of IVF success rates based on an individual’s medical history and age.

Still have questions about getting pregnant? Check out our fertility FAQ here.

Editors’ note: We use the terms “woman” and “female” in this article to refer to people with internal reproductive organs; however we understand that not everyone with internal reproductive organs identifies as a woman or a female. We use the terms “man” and “male” to refer to people with external reproductive organs; however we understand that not everyone with external reproductive organs identifies as a man or a male.