To demonstrate a possible beneficial impact of pertubation we designed a randomized prospective study, in which uterine washing was administered prior to insemination in patients diagnosed with unexplained infertility.

Inclusion Criteria:

• age of 18-44 years; presence of regular menstrual cycles and ovulation; absence of tubal occlusion on HSG; sperm concentration >15 million spermatozoa/ml and total sperm number >39 million/ml according to WHO criteria

Exclusion Criteria:

• the presence of endocrinologic disease; use of nonsteroidal anti-inflammatory drugs (NSAIDs) or corticosteroids; clinical findings suggestive of pelvic inflammatory disease; and the presence of undiagnosed uterine bleeding