In most instances, we are unable to determine the exact cause of the miscarriage.
The pregnancy that miscarries is probably abnormal from the beginning. At the time of conception, the baby receives half the genes form the sperm and half from the egg. For unknown reasons, at this crucial time of the baby's development, some of the genetic information is lost. This results in a baby that has no chance of developing normally, resulting eventually in a miscarriage.
Certain maternal medical conditions may predispose to miscarriage including uncontrolled severe diabetes, thyroid disease or autoimmune disease.
Another possible cause of miscarriage is that the baby did not implant or bury itself in the womb lining properly.
What is certain is that a miscarriage does NOT result from eating specific foods, carrying heavy things, exercise or sexual intercourse. In short, a miscarriage does not occur as a direct result of something you or your partner has done during the pregnancy.