Insemination is used especially if sperm production is mildly impaired or the cause of infertility remains unexplained. With insemination, the probability of pregnancy is about 10–15 percent per attempt. Most pregnancies begin during the first 3–4 treatment cycles.
In insemination, the most motile sperm are separated from the seminal fluid by means of a technique known as sperm washing and injected into the uterine cavity at the time of ovulation. Insemination may be carried out within the natural menstrual cycle or, if necessary, together with ovulation induction treatment.