Placenta membranacea is associated with a very poor fetal outcome.
[aafp.org]
[…] fetal outcome Placental bleeding (e.g., abruption) Clot, especially an adherent clot toward the center of the placenta, with distortion of placental shape Associated with
[aafp.org]
Fibrin deposits are gray and, if extensive, may be associated with intrauterine growth retardation and other poor fetal outcomes.
[aafp.org]