Pregnancy loss remains common around the world. About 15 percent of known pregnancies end in miscarriage , although the true number is likely much higher, since many pregnancies are lost before they are discovered. In a new study, researchers uncovered key information about genetic factors related to aneuploidy, or an abnormality in the number of chromosomes in a cell – one of the most common causes of pregnancy loss. A miscarriage can occur for a variety of reasons , but chromosomal