Article Female Fertilization in Vitro Humans Oocytes Placenta Placenta Diseases Pregnancy Pregnancy, Multiple Retrospective Studies adult adverse event autologous IVF autotransplantation clinical effectiveness cohort analysis controlled study donor IVF donor selection female fetus death high risk pregnancy human in vitro fertilisation in vitro fertilization ischaemic placental disease ischemic placental disease major clinical study mediation analysis multifoetal gestations