Book excerpt: "1 Clinical history, clinical correlations with placental pathology and prematurity The initial steps in the process of perinatal nervous system evaluation, namely the planning of the optimal approach and choice of samples to be obtained, are driven by the clinical context. Of key importance are the following data: a. Gestational age at time of demise (if stillborn); or gestational age and postnatal age (if liveborn), for comparison with normative standards of development (see Appendix); b. State of maternal health (age, parity, pre-existing medical conditions or ones appearing during gestation or around the time of delivery, exposure to medications/toxins/infections), and of health of siblings or other family members: - Concerns for inherited (i.e., genetic) conditions, metabolic disorders, congenital infections, etc., may indicate the need for special testing; c. Details of prenatal course, including any imaging, amniocentesis, or monitoring: - Prenatal imaging modalities most commonly consist of transabdominal ultrasonography, generally done at the time of the first prenatal visit (to confirm pregnancy) or more usually in the mid-second-trimester for detection of fetal or placental anomalies"--