An Overview of Intrauterine Insemination (IUI)

Medically reviewed by Eduardo Hariton, M.D., M.B.A.

When you first begin your conception journey, one of the first lines of defense taken by a fertility doctor is often Intrauterine Insemination (IUI). Sperm is placed directly into the uterus using a small catheter during this procedure. This treatment aims to improve the chances of fertilization by increasing the number of healthy sperm that reach the fallopian tubes when a woman is most fertile.

6 Second Snapshot

  • IUI places sperm inside the uterus during ovulation, making the distance it needs to travel to meet the egg much shorter.
  • There are several medication options when it comes to IUI, including forgoing medication altogether.
  • If you’re over 40 years old, you may want to ask your doctor if IVF is a better option for you.
  • It's recommended to stop after 3-4 IUIs as the likelihood of success with additional tries significantly decreases.

The IUI Procedure

IUIs, unlike IVF, do not require injectable medications to increase egg production, but most women use some form of oral medication to maximize IUI pregnancy potential.

IUI is planned around a woman's ovulation cycle. While ovulation is tracked, sperm is collected (either fresh or frozen) and washed in a lab to concentrate the best quality sperm available. The actual IUI procedure involves a doctor placing the sperm in the uterine cavity through a small catheter – essentially fast-tracking the sperm's journey to meet the ovulated egg(s). Some women describe the procedure as feeling similar to a pap smear.

While the laboratory portion of the IUI procedure is now complete, the sperm still has a lot of work to do! It must:

  1. Reach the fallopian tubes (where fertilization happens)
  2. Combine with an egg to form an embryo (fertilization)
  3. Attach to the uterus and grow (implantation)

Different IUI Protocols

Deciding which medication protocol is right for you should be determined with your doctor.

Non-Medicated Cycle: Forgoing medication altogether might make sense for single mothers by choice, same-sex couples, and male partners with mild infertility for a first IUI cycle.

Medicated Cycle: A medicated cycle is when IUI is done in conjunction with fertility drugs that stimulate your body to mature and ovulate multiple eggs. This process goes by many names, including superovulation, controlled ovarian hyperstimulation, and ovulation induction by hormone therapy.

  • Oral medications: Clomiphene Citrate (Clomid) or Letrozole (Femara) are most common.
  • Injectable medication: Gonadotropins (FSH/LH) are more typically used in IVF but can often be used in IUI cycles for patients who do not respond to oral medication.
  • Trigger cycle: HCG hormone that can be used in conjunction with a medicated IUI cycle to kick start ovulation.

How much does IUI cost?

The cost range of an IUI cycle can vary vastly — from approximately $200 to $6,000 — depending on various factors, including medication protocol and monitoring frequency.

How successful is IUI?

IUI success rates can be very deceiving. Studies reflect a range of ages, fertility factors, and medication protocols, making it extremely difficult to find reliable statistics.

When looking at IUI data, make sure you read the fine print. IUI can be successful but often requires multiple attempts to achieve pregnancy. Based on quantifiable data (time to pregnancy and cost) vs. unquantifiable data (physical and emotional toll), it is important to decide with your provider what the best first step is for you.

One commonly cited reference is The New England Journal of Medicine's 2015 "AMIGOS" trial, which provides data on the efficacy of IUI over four cycles. This data is compiled from 4 cycles of IUI or until reported pregnancy.

Live Birth percentage: 4 Cycles of IUI

Live birth rateLive births with multiples
Live birth rate
Live births with multiples

Source: NEJM, 2015

What risks are associated with IUI?

Because ovarian stimulation medications put your ovaries into overdrive, more than one egg can be released during an IUI cycle, dramatically increasing the chance of twins or even multiple babies. Taking injectable medications during an IUI makes this risk even greater, as more follicles typically grow.

In contrast, IVF, previously associated with multiple births, has moved toward the standardization of SET (single embryo transfer), significantly lowering the risk of multiples and higher-risk pregnancies.

Should women over 40 try IUI?

It depends. Women 40 and older are more likely to forgo IUI and proceed straight to IVF, but one size does not fit all, and it's best to discuss this with your doctor.

  1. Time: Trying 2-4 cycles of IUIs will take time, and women over 40 years old may experience a more meaningful decline in ovarian reserve during that period. – a very valuable commodity when going through IVF.
  2. Genetic testing: Unlike IVF, you cannot do genetic testing in an IUI cycle. Since chromosomal abnormalities increase the older, a woman gets, genetically screening embryos before a transfer is typically done for most women over 40.
  3. Multiples: Some women do not feel comfortable carrying or having twins, and for some, this can be very risky in pregnancy, given pre-existing conditions. In those instances, IVF with single embryo transfer upfront may be preferred.

When does it make sense to move onto IVF?

After 3 to 4 failed IUI cycles, it is typically recommended that a patient moves onto IVF. There are a few reasons this makes sense:

  1. Cost: Due to laws of diminishing return, more than three failed IUIs not only begins to get expensive, but your chance of success with each additional IUI attempt significantly decreases.
  2. Embryo storage: Unlike IVF, with IUI, you will not have extra embryos to freeze for another attempt. This may be an important consideration from a financial standpoint and a physical and emotional impact.

For a comparison of IVF vs. IUI, click here.


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