SPERM WITH VERY LOW MOTILE DENSITY (MD) MAY BE A CAUSE OF REDUCED CHANCE OF LIVE DELIVERY DESPITE TRANSFER OF NORMAL MORPHOLOGIC EMBRYOS

Abstract

To determine if a male factor, specifically low MD, can reduce the chance of a live baby despite normal fertilization and the production of embryos with good morphology. Prospective comparison study. To eliminate an oocyte factor as a confounding variable, the study selected pairs of patients sharing donor oocytes. The only couples selected were those where the male partners of 1 couple had a MD below <10x106/mL and the other male partner ≥10x106/mL. The low MD group when evaluating outcome was further divided into very low MD of <5x106/mL and 5-9.9x106/mL. Only cycles where both couples had a fresh embryo transfer (ET) on day 3 were included. Intracytoplasmic sperm injection (ICSI) was used for couples where MD was <10x106/mL unless strict morphology was ≤4% when ICSI was used even with normal MD. There were 242 ETs in low MD groups and 245 in normal MD group.Tabled 1Comparison of in vitro fertilization (IVF) outcome according to MD in pairs sharing oocytesMotile Density (10x106/mL)<55-9.9≥10# transfers14399245% fertilized72.1%70.9%70.9%% 6-8 cell day 357.3%60.2%62.4%% clinical preg./transfer47.6%49.5%56.3%% miscarriage/clinical preg. live20.6%8.2%16.7%% delivered37.8%45.5%46.9%% implantation26.5%26.7%30.9%Chi-square = NS. Power analysis showed one would need to triple the number of subjects to show that the difference in live delivery rates comparing very low MD vs. normal MD was significant. Evaluating a subset with normal morphology using strict criteria, the live delivered pregnancy rate for very low MD was 36.1% (26/72) vs. 48.3% and miscarriage rate was 29.7% vs. 13.3%. Thus, low strict morphology was not a confounding variable. Since both low MD groups had ICSI performed, and the less severe group did as well as the normal MD group, ICSI did not seem to be a confounding variable. There was an average of 1.8 embryos transferred in the very low MD group vs. 1.9 in the normal MD group. Open table in a new tab Chi-square = NS. Power analysis showed one would need to triple the number of subjects to show that the difference in live delivery rates comparing very low MD vs. normal MD was significant. Evaluating a subset with normal morphology using strict criteria, the live delivered pregnancy rate for very low MD was 36.1% (26/72) vs. 48.3% and miscarriage rate was 29.7% vs. 13.3%. Thus, low strict morphology was not a confounding variable. Since both low MD groups had ICSI performed, and the less severe group did as well as the normal MD group, ICSI did not seem to be a confounding variable. There was an average of 1.8 embryos transferred in the very low MD group vs. 1.9 in the normal MD group. Though the differences were not significant, possibly the results could suggest that even using the best quality oocytes, males with very low MD may be responsible for unexplained failure to achieve a live birth even with the transfer of normal quality embryos by morphologic criteria. Since good oocytes can sometimes correct sperm defects, it may be that these differences may be even greater if the oocytes retrieved are of less quality. Thus, in cases of repeated failure to achieve live deliveries in couples where the sperm has very low MD, instead of switching to donor oocytes, one could consider first trying donor sperm. A larger possibly multicenter study is needed to support or refute this suggested cause of unexplained infertility.