What is the Difference Between IUI and IVF?

When it comes to fertility treatments, two of the most common options are Intrauterine Insemination (IUI) and In Vitro Fertilization (IVF). Each has its unique approach, success rates, and suitability based on individual circumstances. Dr. Adrienne Neithardt, a reproductive endocrinologist at Boston IVF, provides insight into the key differences between these treatments and how to determine which one might be right for you.

What is IUI?
Intrauterine Insemination (IUI) is a less invasive fertility treatment where sperm is collected and directly inserted into the uterus around the time of ovulation. This procedure can be done with a natural cycle or combined with medications like Clomid or Letrozole to stimulate ovulation.

IUI is often a starting point for:

• Couples with unexplained infertility.
• Individuals with ovulation issues, where oral fertility drugs can help regulate egg release.
• Couples with mild male factor infertility (low sperm count or motility).
• Single individuals with a uterus or couples using donor sperm.

For IUI to be effective, it’s essential that the patient has open Fallopian tubes, as fertilization takes place within the tubes after the sperm meets the egg.

What is IVF?
In Vitro Fertilization (IVF) is a more advanced treatment where eggs are retrieved from the ovaries, fertilized with sperm in a lab, and then an embryo is transferred to the uterus. IVF involves several steps, including ovarian stimulation with injectable fertility drugs, egg retrieval, fertilization in the lab, and embryo transfer.

IVF is recommended in cases such as:

• Blocked Fallopian tubes where natural fertilization is impossible.
• Severe male factor infertility, where sperm may need to be injected directly into the egg (ICSI).
• Advanced maternal age or diminished ovarian reserve, where the chances of natural conception are lower.
• Genetic conditions, where preimplantation genetic testing (PGT) can ensure only healthy embryos are transferred.
• Repeated IUI failures, where a more aggressive treatment may offer better chances.

Comparing Success Rates
One of the biggest factors in choosing between IUI and IVF is success rates. IVF tends to have higher success rates per cycle than IUI. Dr. Neithardt explains that IUI aims to bring a patient back to a "normal" fertility rate of about 10-20% per cycle, similar to the chances a fertile straight couple has of conceiving each month. IVF, on the other hand, offers success rates between 25-60% per cycle, depending on age and diagnosis.

When to Consider IUI
IUI is a good first step for younger people with no significant fertility issues or those using donor sperm. It’s less invasive and less expensive than IVF, making it a popular initial treatment for couples trying to conceive.

When to Skip IUI and Go Straight to IVF
For some patients, particularly those with diminished ovarian reserve, older reproductive age, or severe male infertility, Dr. Neithardt advises skipping IUI and moving directly to IVF. IVF can offer a much higher chance of success, especially for those facing more time-sensitive or complex fertility challenges​.

The Advantage of IVF for Family Planning
One benefit of IVF is that it often results in extra embryos, which can be frozen for future use. This can be especially advantageous for couples planning multiple children. Rather than starting from scratch with IUI each time, IVF allows for embryo preservation, providing a quicker and more efficient path to building a family over time.

Final Thoughts
Choosing between IUI and IVF depends on many factors, including your age, fertility diagnosis, and personal goals. While IUI is less invasive and more cost-effective, IVF offers higher success rates and is more suitable for complex fertility issues. Dr. Neithardt emphasizes the importance of discussing your unique situation with a fertility specialist to determine the best course of action.