The Hypo-osmotic Swelling Test in Recurrent Miscarriage

Objective: To determine whether there is any association between sperm membrane integrity as determined by the hypo-osmotic swelling test score and unexplained recurrent miscarriage.

Design: Prospective observational study.

Setting: Tertiary referral center for recurrent miscarriage.

Patient(s): Semen samples from 20 male partners of women who had had three or more first trimester miscarriages of unexplained etiology and semen samples from 20 prospective semen donors of unknown fertility potential.

Main Outcome Measure(s): Sperm density, sperm motility, sperm morphology, and hypoosmotic swelling test score.

Result(s): There was no difference in the median sperm density, the mean sperm motility, or the mean sperm morphology between the two groups. However, the recurrent miscarriage group had a significantly lower hypo-osmotic swelling test score than the control group.

Conclusion(s): The hypo-osmotic swelling test score is significantly lower in samples from men whose partners have had unexplained recurrent spontaneous abortions. With the exception of cytogenetic abnormalities in peripheral blood karyotype, this is the first study to identify a male factor component in recurrent miscarriage.