Doctors urge sperm DNA damage testing after repeated miscarriages

A new clinical guideline says men should get tested for sperm DNA damage if their partners suffer repeated miscarriages. The advice, published this week by the European Society of Human Reproduction and Embryology, marks the first time major fertility bodies have recommended routine sperm DNA fragmentation testing after two or more unexplained losses.

The shift comes after dozens of studies over the past decade showed that damaged sperm DNA—caused by oxidative stress, smoking, obesity or chemotherapy—can stop an embryo from implanting or trigger early miscarriage, even when standard semen tests look normal. Guidelines previously focused only on the woman’s age, hormone levels and uterus. Now experts say half of couples with recurrent miscarriage may get no clear answer unless the man is tested too. The new rule applies to couples trying naturally or through IVF; testing costs about $200 and is not yet widely covered by insurance.

In one 2022 study of 350 couples, 45% of men whose partners had three or more miscarriages had high DNA fragmentation scores, compared with 20% in the general population. Fertility doctors report that when men with high scores switch to antioxidant therapy or use donor sperm in IVF, the next pregnancy succeeds in roughly two-thirds of cases. Still, many clinics have been slow to adopt the test because they lack standardized thresholds for what counts as “high damage.”

Next year the World Health Organization plans to publish its first manual on sperm DNA testing, which should set global cut-offs and push more labs to offer the assay. Until then, fertility centers in Europe and North America are quietly adding the test to standard work-ups for recurrent miscarriage. Experts say the change could spare thousands of couples months of uncertainty and unnecessary hormone treatments while steering more men toward lifestyle fixes that improve sperm quality.