The effects of vaginal lubricants on sperm function: an in vitro analysis

Despite being marketed as "sperm friendly", some vaginal lubricants are known to be detrimental to sperm function and therefore could negatively affect fertility. Many others have not yet been assessed in regards to their effect on sperm function. This issue may concern couples trying to conceive both naturally and via artificial reproductive technologies (ART).

The aim of this research was to analyse the effects that lubricants, commonly used in the setting of natural conception and ART, have on sperm function in an in vitro setting. This was done by assessing sperm motility, vitality and DNA fragmentation following treatment with commercial lubricants or control preparations. We have attempted to mimic the conditions of the vaginal environment in our clinical trial, and so have compiled a list of lubricants that are likely to have minimal negative effect on sperm function in vivo or are "sperm friendly".

Ten samples were obtained for the study from patients attending a fertility clinic. Once collected, the sperm samples were prepared by density gradient centrifugation and incubated with 11 different lubricants including positive and negative controls for 30 min at 37 °C to mimic the temperature inside the female reproductive tract. Sperm motility, vitality and DNA fragmentation were assessed to determine the effects of the lubricants on sperm function and DNA integrity.

Nine lubricants were investigated including Sylk™, Conceive Plus®, glycerol, Johnson's® Baby Oil, SAGE® Culture Oil, Yes®, Forelife™, MaybeBaby® and Pre-seed®. The lubricant which had the best results in terms of vitality, at 92%, was Pre-seed® and the worst was Forelife™ with 28% vitality. In terms of motility, Pre-seed® resulted in the highest percentage of spermatozoa with progressive motility at 86% and Sylk™ resulted in the lowest percentage of progressively motile cells in the sample with 31% of sperm progressively motile. There were no significant effects on DNA integrity.

Pre-seed® was the lubricant which had the least negative effect on sperm function, with Conceive Plus® a close second, due to the significantly higher sperm motility and vitality parameters measured following lubricant exposure.