Is there a statistic available for patients with unexplained infertility who actually fall pregnant using IUI? Is there an average amount of IUI cycles it took to achieve pregnancy?
Should a patient with unexplained infertility rather move on to IVF sooner? How soon?
In-utero insemination (IUI) is the appropriate assisted reproduction option in the context of normal (patent) fallopian tubes and mild male factor infertility, for mild endometriosis (without anatomic distortion), following failed ovulation induction cycles and in unexplained infertility. IUI with controlled ovarian stimulation does have significantly higher pregnancy rates than ovulation induction alone. The pregnancy rate will depend on the age of the female partner (including assessment of ovarian reserve) and the extent of a male factor (sperm count, motility, morphology etc). The pregnancy rate per treatment cycle is 20% for women <35 years of age, 16% for 35-39 years of age and 9% for women older than 39. There is, however, a plateau in the pregnancy rate with IUI – i.e. if pregnancy is not achieved within the first 3-4 treatment cycles, there is a diminishing chance of pregnancy in subsequent cycles. This is reflected in the cumulative pregnancy rate after 6 months of treatment with IUI, which is 40% for women <35, 26% for women 35-39 years of age and 12% for women older than 39.
Pregnancy rate is also affected by the duration of infertility, with couples who have been struggling to conceive for 3 or more years having a lower pregnancy rate.
If IUI is not successful after 3-4 treatment cycles, then the next assisted reproduction option is in-vitro fertilisation (IVF) with/without intra-cytoplasmic sperm injection (ICSI). This recommendation would be the same for patients with unexplained infertility. Women older than 39 may be encouraged to proceed directly to IVF/ICSI, due to the lower pregnancy rates for IUI in this age group.