According to Doula UK , a doula is someone who supports women and their families during pregnancy, childbirth and early parenthood. This support is practical and emotional but non-medical in nature.
Basically, a doula is someone who is there for the mother. Though on a whole, a doula is there for the entire family, first and foremost a doula is there for the mother. A doula is not someone that can do examinations or any interventions of a medical nature (midwives are great at their jobs and a doula is not a midwife!), or make decisions for someone else. A doula can be what you need her to be, whether this is, for example, a listening ear, someone to lean on (literally!), someone to entertain an older child, someone to help guard your personal space.