From the Guidelines
At least three cycles of Intrauterine Insemination (IUI) are recommended for couples with unexplained infertility and a total motile sperm count (TMSC) of >10 million, as this has been shown to be the most effective option. This recommendation is based on the most recent and highest quality evidence available, including a study published in the Human Reproduction Update journal in 2018 1. The study suggests that IUI is a cost-effective first-line therapy for heterosexual couples with infertility linked to cervical factor, endometriosis, unexplained infertility, and relatively mild male factor infertility.
When considering IUI, several factors influence the success rates, including:
- Age of the female partner
- Fertility diagnosis
- Use of fertility medications
- TMSC of the male partner Each IUI cycle typically takes 2-4 weeks to complete and involves ovulation monitoring, possible fertility medication administration, and the insemination procedure itself. The actual insemination procedure is quick, taking only about 5-10 minutes in a doctor's office.
It is essential to note that the cumulative success rate of IUI increases with each attempt, which is why multiple cycles are typically recommended before moving to more invasive treatments like IVF. However, if no pregnancy occurs after 3-4 IUI cycles, doctors often recommend reassessing the treatment plan or considering more advanced options. A study by Reindollar et al. (2010) found that clomiphone 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 was the most cost-effective approach 1.
In addition, another study by Bensdorp et al. (2015) showed that IUI-OS was non-inferior to IVF with SET or IVF in a MNC, with an outcome indicator of a healthy live birth, 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. Therefore, at least three cycles of IUI are recommended before considering other fertility treatments, taking into account the individual circumstances and fertility status of each couple.
From the Research
Number of Intrauterine Insemination (IUI) Cycles
- The optimal number of IUI cycles is a topic of ongoing debate, with various studies providing different recommendations 2, 3, 4, 5, 6.
- A study published in 2022 found that approximately 98% of pregnancies occurred in the first 3 cycles of IUI, and recommended three attempts of IUI for PCOS women before switching to IVF/ICSI 2.
- Another study from 2015 suggested performing up to four insemination cycles before proceeding to IVF/ICSI cycle, as the increment of the cumulative biochemical pregnancy rate was observed up to four cycles 3.
- A systematic review from 2022 recommended considering OI/IUI for up to 4 cycles in women using partner sperm or 6 cycles with donor sperm, as the majority of pregnancies occurred in the first 6 cycles 4.
- A retrospective multicentric cohort study from 2019 found that live birth rate (LBR) was below 7% from 40 years of age on, and no significant differences were observed among populational groups studied 5.
- A multicentre, retrospective cohort analysis from 2008 found that ongoing pregnancy rates (OPR) in high-order IUI cycles were acceptable, and did not offer a rationale for cancellation before nine cycles 6.
Factors Affecting IUI Success
- Female age is a significant factor affecting IUI success, with LBR decreasing with advancing age 3, 4, 5.
- The type of subfertility, diagnosis, use of hyperstimulation, or cycle number did not have a significant impact on OPR after the sixth treatment cycle 6.
- The use of gonadotropins does not appear to be more effective than oral agents in women over 40 years old 4.