Evaluation of the effect of a cervical cap device on sperm functional characteristics in vitro

Intracervical insemination continues to be employed for homologous and donor insemination in natural and stimulated cycles. Efficacy studies for potential fertility involve in vivo assessment; however, in vitro testing of particular sperm function(s) critically involved in fertilization is an important component of such evaluation. We report here on the in vitro evaluation of the effects of the silicone Veos cervical cap (Veos, London, UK) on sperm function. Donor semen was exposed to the Veos cervical cap or a sterile 15-cc centrifuge tube (control), or treated with the spermicide nonoxynol-9 (5 mg x ml(-1) in saline) for 4 h at 37 degrees C and 5% CO2 in water-saturated air. After exposure, motility characteristics, both in semen and in spermatozoa processed by standard swim-up procedure, cervical mucus penetration and sperm-zona pellucida interaction using the hemizona assay were assessed. Results indicated that exposure to the Veos cervical cap had no effect on either sperm motility characteristics or sperm-zona pellucida interaction. A small but significant difference was observed for cervical mucus penetration (P = 0.05); however, for both the control and treated groups, vanguard spermatozoa exceeded manufacturer's guidelines for a normal test, a penetration distance of > or = 30 mm. As expected, nonoxynol-9 was a potent inhibitor of sperm function. Lack of adverse effects on in vitro spermatozoa functional characteristics after exposure to the silicone Veos cervical cap supports its addition to the repertoire of fertility treatment modalities when cervical insemination is indicated.