Introduction

Advances in obstetrical ultrasound, combined with ancillary magnetic resonance imaging and rapid molecular testing of amniotic fluid, have greatly improved our diagnostic capabilities when assessing the fetus with suspected intrauterine growth restriction (IUGR). Despite these advances, several frustrating issues confront clinicians when managing suspected IUGR as follows. First, an unacceptably high false-positive rate for the diagnosis of IUGR in later gestation increases unnecessary interventions (induction of labor and/or Cesarean delivery) and iatrogenic morbidity in small-for-gestational-age newborns. As an example, 33.4% of 650 women recruited to the recently published DIGITAT (Disproportionate Intrauterine Growth Intervention Trial at Term) trial had no postnatal evidence of IUGR (birth weight <10th percentile) [1]. Second, clinician uncertainty regarding cause or prognosis for suspected IUGR may trigger frequent short-term tests of fetal well-being (biophysical profile ultrasounds and non-stress tests) even via hospital admission, in the absence of any objective diagnosis. Third, in the absence of a perinatal and placental pathology service, clinicians have only proxy markers of disease, reflected by performance in labor and short-term neonatal morbidity, to audit their decision-making. A common solution to improving clinical practice in IUGR management may therefore be found in a reappraisal of the value of placental pathology to guide maternal-fetal medicine and obstetric practice. This chapter will review the pathological basis of placental IUGR that is meaningful to everyday practice, so that “placentology” can be integrated into obstetric and postpartum care.