Effectiveness of pentoxifylline in semen preparation for intrauterine insemination

Pentoxifylline, an inhibitor of cAMP phosphodiesterase activity, favours intracellular cAMP concentration increase. In-vitro treatment of semen with pentoxifylline leads to marked augmentation of sperm motility, enhancement of acrosome reaction, increase of sperm penetration into zona-free hamster oocytes, and protection of the sperm plasma membrane. Such properties indicate that the drug may be a useful tool for semen preparation in assisted reproduction, but its real effectiveness in improving fertilization rates is still uncertain, mainly in association with intrauterine insemination (IUI). Theoretically sperm motility should play an extremely important role for positive results in IUI. Therefore, a retrospective clinical trial was planned in order to evaluate whether addition of pentoxifylline to the previously standardized in-vitro treatment of semen had improved the percentage of pregnancies after homologous IUI. The study involved 55 sterile couples (33 classified infertile for male factor and 22 for other factors) who underwent a total of 150 cycles of homologous IUI: 101 for male factor infertility and 49 for other factors (anovulation n = 26, endometriosis n = 2, idiopathic n = 21). Out of the 101 cycles performed for male factor infertility, 61 underwent the standard preparation of semen and were followed by seven pregnancies (pregnancy rate = 11.5%) while 40 had a semen preparation with pentoxifylline addition and were followed by 11 pregnancies (pregnancy rate = 27.5%) with a significant difference between the two procedures (P < 0.05). Out of the 49 cycles carried out for factors different from male infertility, 10 underwent the standard preparation of semen and were followed by two pregnancies (pregnancy rate = 20.0%), while 39 had pentoxifylline addition and were followed by nine pregnancies (pregnancy rate = 23.1%). The difference between the two groups was not significant. Abortions and malformations were equally distributed in the standard treatment and in the pentoxifylline group.