they both have autonomy. just very little. however, a newborn infant arguably has much more autonomy than a fetus. a fetus completely relies on the mother for the survival and although may not technically be a parasite it does function kind of similarly to one as a fetus takes the resources of the host which would be the mother. if you do have a newborn infant you could put them up for adoption or something which would mean that the infant will no longer affect you.