Thanks for the query to H.C.M. Forum.Missed abortion
may be due to many reasons .
1 Therapeutic incompatability , diagnosis can be confirmed by blood examination for grouping .
2 Any abnormality during implantation
, diagnosis can be confirmed by ultrasound
3 Uterine pathology, diagnosis can be confirmed by physical as well as ultrasound of uterus.
In my opinion sperms are not responsible for missed abortion. Once fertilization , no role of sperm in missed abortion.
In my opinion consult a gynecologist and get his opinion.