How should I do heparin injections while pregnant?

Notvsure. Must be given a reason to be treated with Heparin it is usually given subctaneously.
Consult with a nurse. Nurses know a lot more about how to give shots than doctors since we don't usually give medications. I would review with a registered nurse. Briefly you rotate sites on your abdomen. You want to pinch a generous amount of skin between your fingers to give the shot. Avoid a place that looks bruised. Do not aspirate or pull back before giving the shot.