Adverse Pregnancy Outcome

The goal of this randomized clinical trial is to evaluate if we can use placental pathology in a prior pregnancy which had an adverse outcome, such as early delivery, stillbirth, a baby born smaller than expected, or severe forms of high blood pressure during pregnancy, to guide treatment in the subsequent pregnancy and reduce risk of recurrent adverse pregnancy events. The main questions it aims to answer are: * Whether enoxaparin prevents recurrent adverse pregnancy outcomes among patients with a prior adverse pregnancy outcome that occurred in the setting of maternal vascular malperfusion (MVM). * If enoxaparin reduces the occurrence or severity of MVM among patients with a prior adverse pregnancy outcome that occurred in the setting of MVM.