Recurrent obstetric complications: how placental pathology can contribute to cost-effective clinical evaluation and a rational clinical care plan.

When a pregnancy is delivered with unexpected outcomes and the potential for newborn risk (growth restriction, preterm birth, preeclampsia) or a pregnancy fails, this fact carries risks for future obstetric complications. There is an ever-expanding range of laboratory tests for patients with "obstetric compromise, not otherwise specified." How can you interpret these test results to give surveillance and treatment only to those patients who will benefit? Four major patterns of placental tissue injury may be distinguished reliably by routine microscopy (acute inflammation, chronic inflammation, maternal/uteroplacental vascular pathology, and clotting problems). For the clinician, this information may serve as a guide to cost-effective and rational patient evaluation and next-pregnancy management.