What causes miscarriageNew clinical research centers all over the county are helping women solve the mystery of miscarriages. Nearly one in four pregnancies end in miscarriage and about 5% of couples experience recurrent pregnancy losses. For half of these losses, the reasons are unclear. The centers then might conduct genetic testing, look for hidden infections or hunt for mysterious immune disorders, among other techniques. “Just knowing a cause, giving an explanation even before there’s a treatment is often very helpful,” says Dr. Zev Williams, director of The Program for Early and Recurrent Pregnancy Loss, or Pearl, located at Albert Einstein College of Medicine and Montefiore Health System in New York City.