IUI vs. IVF vs. ICSI vs. PICSI—What is What? And Why So Many Acronyms?


Looking into fertility treatments can feel a lot like you’re trying to make sense out of all those noodles floating around a bowl of alphabet soup. There’s IUI vs. IVF vs. ICSI vs. PICSI…yeah, that’s a lot of letters.

At first glance, it seems like IUI vs. IVF are similar. They both have an I in them…so maybe they’re related? And what’s with ICSI and PICSI? Is that P just a typo? Don’t worry, you don’t need a crystal ball to figure all of this out. Consider this your secret decoder ring for all those fertility treatment acronyms.

There are plenty of new terms to learn when you’re starting the fertility journey—or at least terms to dig out of your brain from your high school science class days. But there are four major acronyms that tend to come up when you sit down with a fertility doc to talk options.


Short for: Intrauterine insemination (although it’s also sometimes called artificial insemination)

How it works:

  • IUI involves donated or a partner’s sperm being placed in the uterus. Sperm are “washed” (essentially, sorted to weed out the strongest, best swimmers) and injected through a catheter up through the cervix directly into the uterus, at the time of ovulation. That’s the end of expert intervention when it comes to IUI—the goal is for fertilization to occur in the body, up in the fallopian tube, in the same exact way it would if the sperm swam there on its own.
  • This procedure may be combined with medications to induce ovulation, such as Clomid or Letrozole, typically given for three to five days, or medication prescribed after the procedure, like progesterone (which can be used during IUI or IVF).

Who does it: Usually a reproductive endocrinologist, though it can also be performed by a general OB/GYN.


Short for: In vitro fertilization

How it works:

  • IVF typically involves stimulating the ovaries with medications in order to boost the number of eggs you produce and mature them enough to the point of almost ovulating. However, donor eggs can also be used with IVF. If a donor egg is used, the mother-to-be will typically take medications meant to sync her cycle with that of her donor.
  • Next step? A mom-to-be or her donor has to undergo minor surgery to retrieve the eggs. “The eggs are collected using ultrasound guidance, using a syringe to withdraw the eggs from the ovaries,” says Dr. Mary Jane Minkin, M.D., a clinical professor of obstetrics, gynecology and reproductive sciences at the Yale School of Medicine.
  • Eggs are later mixed with donor or a partner’s sperm in a lab—this process is called insemination.
  • If insemination is successful and the embryo continues to mature after a few days, the embryo (or sometimes more than one, depending on your situation) is transferred directly into the uterus by a specialist, again using a catheter. Some first undergo genetic testing to ensure the embryo is chromosomally normal and/or isn’t a carrier for certain conditions. If all goes well, the embryo will implant in the uterus, getting you pregnant.

Who does it: The retrieval and embryo transfer portions of IVF are typically performed by a reproductive endocrinologist, while the insemination process is handled by a clinical embryologist in the fertility clinic lab.


Short for: Intra-cytoplasmic sperm injection (usually pronounced ick-see)

How it works:

  • The ICSI procedure is a part of the IVF cycle that’s often used in cases of male factor infertility, such as poor sperm count or quality, says Dr. Alyssa Dweck, M.D., an OB/GYN at CareMount Medical in Westchester County, NY.
  • A male partner’s sperm is usually collected into a collection cup, though it may be retrieved surgically by a urologist from a male partner’s testes or epididymis (that’s a tube in his testicles where sperm collects).
  • It is then studied in a lab to determine which specific sperm cell (sometimes called the spermatazoa) is the best candidate for potentially inseminating the eggs retrieved during the IVF process. “This technique allows a single sperm to be injected directly into a mature egg,” Dr. Dweck says, hopefully resulting in a fertilized egg.
  • The fertilized egg develops into an embryo, which is then placed in the uterus via the IVF process. And you know where this is going now, right?

Who does it: The ICSI process is typically performed in a fertility clinic or center’s lab by an embryologist.


Short for: Physiological intra-cytoplamsic sperm injection (usually pronounced pick-see)

How it works:

  • No, that P isn’t a typo. PICSI is essentially ICSI with an extra step, says Dr. Jaime Knopman, M.D., a reproductive endocrinologist at New York fertility clinic Colorado Center for Reproductive Medicine (CCRM).
  • This procedure involves adding a special enzyme to the sperm to enhance insemination chances, but it otherwise mirrors ICSI. After an embryo forms, it’s transferred to the uterus, and all fingers crossed…pregnancy hopefully occurs.

Who does it: Like ICSI, PICSI is typically performed by lab specialists called embryologists.

Summing it all up

Starting your fertility journey is a lot like learning a new language, and it can feel a little overwhelming at times. Don’t be afraid to ask your fertility specialist to slow down, back up, and explain if you didn’t understand the medical jargon they threw at you or simply spoke too fast.

And hey, now that you’ve got the big four acronyms under your belt, you can start dropping some knowledge on those Facebook support groups like you’re a pro…or at least understand what the heck they’re all talking about.

Jeanne Sager

Jeanne Sager is a writer and photographer from upstate New York. She's strung words together for The New York Times, The Atlantic, The Washington Post, and more.