Two methods of achieving pregnancies despite subnormal hypo-osmotic swelling test scores

To determine whether either the use of intracytoplasmic sperm injection (ICSI) or chymotrypsin-galactose pretreatment of sperm before IUI can improve pregnancy results in female partners of men with sperm with subnormal hypo-osmotic swelling test scores.

Randomized controlled study.

University-based private practice of an infertility center and IVF center.

Couples with infertility who presented during a specific time interval and in whom the male partner had a hypo-osmotic swelling score of < 50% in two consecutive cycles.

Controls were treated by conventional IUI. Members of the treatment group were given an option of treatment of sperm with chymotrypsin-galactose before undergoing IUI or of undergoing IVF-ET with ICSI.

Pregnancy rate (PR) per patient and per cycle.

None of the 14 control patients conceived despite 38 IUI cycles, whereas conception occurred for 4 (50%) of 8 couples in whom sperm was pretreated with chymotrypsin-galactose and for 2 (50%) of 4 couples who underwent ICSI. Patients who had enzymatic sperm treatment underwent 12 IUI cycles and 4 ICSI cycles; the PR per cycle was 33.3% in the former and 50% in the latter.

These data suggest that treating sperm with chymotrypsin-galactose before IUI or injecting only one sperm into the oocyte overcomes to some degree the block to successful pregnancy seen in women whose male partners have subnormal hypo-osmotic swelling tests.