my girlfriend had a misscarege what could have caused this
It may be difficult for health care providers to know what caused a particular miscarriage. But we do know some things that make miscarriage more likely in general:
Many of us who experience miscarriage are not aware that it is fairly common. For every 10 pregnancies, one to two end in miscarriage. Miscarriage is most likely to happen early in pregnancy — in fact, eight out of 10 miscarriages happen in the first three months of pregnancy.