Multiple studies have reported on the impact of factors such as female age, duration of infertility, type of infertility, hormone levels (i.e. AMH, FSH, estradiol, progesterone), use of different ovarian stimulation protocols, timing/induction of ovulation, number of pre-ovulatory follicles, endometrial thickness by the time of ovulation, sperm parameters (i.e. concentration, progressive motility, morphology, total motile sperm count [TMSC], inseminating motile count [IMC]) and sperm washing procedures. Also the influence of body mass index and smoking on IUI outcome have been studied before. However, results on the predictive value of these parameters remain highly contradictory. The aim of the study is to examine the value of different variables in the prediction of IUI success to develop a clinically useful predictive model of pregnancy and live birth.

Inclusion Criteria:

• couples had been diagnosed with infertility according to WHO definition (failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse)
• at least one permeable tube
• a motile sperm concentration post treatment of 1×106/mL on the day of the semen analysis

The included couples were subjected to an infertility diagnostic work-up. The tests included collecting medical history, physical examination, transvaginal ultrasound, serum hormone assays between day 2 and 4 of the menstrual cycle, semen analysis, uterine cavity and tubal patency evaluation with hysterosalpingography (HSG) or hysterosonosalpingography (HSSG) and/or hysteroscopy and video laparoscopy. Assessment of vaginal infection with cervico-vaginal swab and cultures