USE OF THE ACROSOME REACTION TO IONOPHORE CHALLENGE TEST IN MANAGING PATIENTS IN AN ASSISTED REPRODUCTION PROGRAM - A PROSPECTIVE, DOUBLE-BLIND, RANDOMIZED CONTROLLED-STUDY

Objective: To assess the utility of the acrosome reaction (AR) to iono phore challenge test in determining the sperm treatment protocols for patients undergoing assisted reproduction. Design, Setting, Patients: One hundred twenty-one couples undergoing an IVF-ET or GIFT procedure from January to July 1992 were included in this prospective study. All cases had a preliminary semen analysis within the previous 3 months a nd an AR to ionophore challenge test was carried out unless an accepta ble fertilization rate occurred on previous IVF. For those patients wh ose AR to ionophore challenge score was below the accepted fertile ran ge of greater than or equal to 10%, a second AR to ionophore challenge test was performed after exposure of sperm to the stimulant pentoxify lline. Couples then were managed by assisted reproduction with randomi zed allocation of oocytes for fertilization with a standard sperm prep aration or with added sperm stimulants, either 3.6 mM pentoxifylline a lone or combined with 3.0 mM 2-deoxyadenosine. The study was double-bl ind with neither the patients nor the embryologist knowing the AR to i onophore challenge result at the time of the IVF procedure. Main Outco me Measures: Data from the preliminary semen analyses and AR to ionoph ore challenge scores were correlated with the fertilization rates achi eved using control and treated sperm preparations. The rates of total fertilization failure and the numbers of clinical pregnancies occurrin g in each subgroup were also recorded. Results: All AR to ionophore ch allenge groups showed normal sperm counts except the groups with poor AR to ionophore challenge, which demonstrated reduced sperm counts. Th e group with normal AR to ionophore challenge scores or previous norma l fertilization showed satisfactory fertilization rates with either co ntrol or treated sperm, although some individual cases showed reduced fertilization with treated sperm. The fertilization rate for the group with low AR to ionophore challenge scores improved significantly with pentoxifylline, and the benefit was greatest when this had been predi cted from the AR to ionophore challenge studies. Cases with persisting poor AR to ionophore challenge despite pentoxifylline showed no signi ficant improvement in fertilization rates with sperm exposed to either sperm stimulant regimens. Poor AR to ionophore challenge scores were also predictive of total fertilization failure, but this problem was r educed by sperm stimulation. The AR to ionophore challenge score at 10 % cutoff level showed optimal levels of sensitivity (82.1%), highest n egative predictive value (82.1%), and lowest false negative rate (17.9 %). Conclusions: The AR to ionophore challenge test is useful in the a ssessment and management of the male factor in assisted reproduction. It can be used to identify the majority of cases who will benefit from the use of sperm stimulants.