What is the difference between In Vitro Fertilization (IVF) and Intrauterine Insemination (IUI) for fertility treatment?

From the Guidelines

In cases of unexplained infertility or mild male factor infertility, IUI is recommended as the initial treatment due to its cost-effectiveness and similar success rates compared to IVF, as supported by high-quality evidence from the FASTT trial 1. The main difference between In Vitro Fertilization (IVF) and Intrauterine Insemination (IUI) lies in their procedures, success rates, and costs. IUI is a less invasive procedure where washed sperm is directly inserted into the uterus during ovulation, while IVF involves stimulating the ovaries to produce multiple eggs, which are then fertilized with sperm in a laboratory and transferred back to the uterus.

Key Considerations

• IUI is typically recommended for unexplained infertility, mild male factor issues, or cervical factors, with success rates ranging from 5-20% per cycle 1.
• IVF is more suitable for complex issues like blocked fallopian tubes, severe male factor infertility, diminished ovarian reserve, or after multiple failed IUI cycles, with success rates of 40-50% per cycle for younger patients.
• The cost of IUI is significantly lower, ranging from $500-$4,000 per cycle, compared to $12,000-$20,000 for IVF.

Evidence-Based Recommendations

• According to the FASTT trial, clomiphene citrate-IUI seems to be the best first-line therapy for couples with unexplained infertility, and if not pregnant after three cycles, moving directly to conventional IVF is the most cost-effective approach 1.
• A recent multi-centre randomized non-inferiority trial found that IUI-OS was non-inferior to IVF with SET or IVF in a MNC, with a reasonably low multiple birth rate and was a more cost-effective strategy for heterosexual couples with mild male factor or unexplained infertility with a poor prognosis of becoming pregnant with expectant management 1.

Clinical Implications

• IUI should be withheld when more than two dominant follicles >15 mm or more than five follicles >10 mm at the time of HCG injection or LH surge are present to maintain singleton delivery rates 1.
• The definition of mild male factor infertility is crucial, with some studies using a TMSC of between 3 and 10 million, while others define it as a TMSC above 10 million 1.

Patient Preferences

• Patients prefer IUI over expectant management when their chance of spontaneous conception is below 50 or 40%, and they prefer IUI over IVF up to six treatment cycles 1.
• Clinicians also seem to believe in IUI as a first-line treatment option, with only 4% following the National Institute for Health and Clinical Excellence (NICE) guidelines that advised to stop IUI in cycles with OS 1.

From the Research

Overview of IVF and IUI

• In Vitro Fertilization (IVF) and Intrauterine Insemination (IUI) are two common fertility treatments used to help individuals or couples conceive.
• The main difference between IVF and IUI lies in the method of fertilization and the level of invasiveness [ 2 ].

Effectiveness of IVF and IUI

• IUI is often recommended as the first-line treatment for unexplained infertility, especially in women under 38 years old, due to its lower invasiveness and cost [ 3 ].
• However, IVF is generally more effective than IUI, especially in cases of severe male factor infertility, tubal damage, or advanced maternal age [ 4 ].
• The effectiveness of IUI and IVF also depends on factors such as sperm quality, ovulation, and the presence of any underlying medical conditions [ 2 ].

Treatment Recommendations

• For couples with unexplained infertility, 3-4 cycles of IUI with ovarian stimulation may be recommended before considering IVF [ 4 ].
• In women over 40 years old, IVF is often recommended as the primary treatment option due to the declining efficacy of IUI with advancing age [ 5 ].
• The choice of treatment ultimately depends on individual circumstances, including the woman's age, duration of infertility, and underlying medical conditions [ 6 ].

Considerations for Treatment Choice

• IUI is generally less expensive and less invasive than IVF, but may require multiple cycles to achieve pregnancy [ 3 ].
• IVF, on the other hand, offers a higher success rate per cycle, but is more expensive and invasive [ 2 ].
• The decision to pursue IUI or IVF should be made after careful consideration of these factors and discussion with a healthcare provider [ 4 ].