Is It Safe For The Fetus To Be Inside The Womb After Miscarriage?

how long can the baby stay inside moms tummy?i had a miacarriage yesterday(april 4)..no bleeding..my baby had no heart rate.but my doctor said that i need an observation until on monday( april 11) waiting for my bleeding..because he wanted a natural procedure for me.until now my baby is still inside my womb. is it safe for me?