Development and in vitro testing of a new method of urine preparation for retrograde ejaculation; the Liverpool solution

Objective To design a new method for oral preparation of urine for sperm retrieval after retrograde ejaculation (RE) and to test the motility of sperm exposed to prepared and unprepared urine. Design In vitro testing of urine conditions and sperm motility. Setting Assisted conception unit at a teaching hospital in the United Kingdom. Patient(s) Ten healthy volunteers to provide urine and sperm specimens from men attending the unit for semen analysis. Intervention(s) Various solutions of sodium bicarbonate and sodium chloride were drunk by a single subject until a suitable regimen was achieved. This regimen (called the Liverpool solution) was then tested on 10 volunteers. Samples of sperm were then added to prepared urine, unprepared urine, and culture medium, and the motility was analyzed. Main Outcome Measure(s) Urinary pH and osmolarity, sperm motility. Result(s) Urine produced by the 10 volunteers had a mean pH of 7.47 (range, 7.23–7.79) and a mean osmolarity of 289 mOsmol/L (range, 225–412 mOsmol/L), similar to that of medium. The progressive motility of sperm exposed to the unprepared urine was reduced (42.4% of sperm in medium), whereas that in the prepared urine was similar to that in the control medium. Conclusion(s) Liverpool solution can be used in any unit treating couples with RE, and it is a noninvasive and inexpensive regimen that may optimize urine pH and osmolarity for sperm survival after RE.