How can you prove a mother is causing harm to her unborn child?

You didn't explain what this young mother-to-be was doing to harm her baby. Smoking, drugs, alcohol, trying to get rid of the baby. There isn't much you can do as she's the mother and has a right to her own body. When the baby is born and if she mistreats her newborn then you can call Children's Aid. == More Contributor Input== Unfortunately, in the US a woman cannot be legally forced to follow a healthy live style when she is pregnant. In the majority of US states when a baby is born addicted to drugs or AFS, the attending physicians/hospital are required to notify authorities.