Chapter 2: The Newborn Infant

INTRODUCTION

The newborn period is defined as the first 28 days of life. In practice, however, sick or very immature infants may require neonatal care for many months. There are four levels of newborn care. Level 1 refers to basic care of well newborns, neonatal resuscitation, and stabilization prior to transport. Level 2 refers to specialty neonatal care of premature infants greater than 1500 g or more than 32 weeks’ gestation. Level 3 is subspecialty care of higher complexity neonates without limitations based on newborn size and gestational age. Level 4 includes availability of specialized pediatric surgery, cardiac surgery, and extracorporeal membrane oxygenation (ECMO). Level 4 care is often part of a perinatal center offering critical care and transport to the high-risk mother and fetus as well as the newborn infant.

THE NEONATAL HISTORY

The newborn medical history has three key components:

1. Maternal and paternal medical and genetic history

2. Maternal past obstetric history

3. Current antepartum and intrapartum obstetric history

The mother’s medical history includes chronic medical conditions, medications taken during pregnancy, unusual dietary habits, smoking history, substance abuse history, occupational exposure to chemicals or infections of potential risk to the fetus, and any social history that might increase the risk for parenting problems and child abuse. Family illnesses and a history of congenital anomalies with genetic implications should be sought. The past obstetric history includes maternal age, gravidity, parity, blood type, and pregnancy outcomes. The current obstetric history includes the results of procedures during the current pregnancy such as ultrasound, amniocentesis, screening tests (rubella antibody, hepatitis B surface antigen [HBsAg], serum quadruple screen for genetic disorders, HIV [human immunodeficiency virus]), and antepartum tests of fetal well-being (eg, biophysical profiles, nonstress tests, or Doppler assessment of fetal blood flow patterns). Pregnancy-related maternal complications such as urinary tract infection, pregnancy-induced hypertension, eclampsia, gestational diabetes, vaginal bleeding, and preterm labor should be documented. Significant peripartum events include duration of ruptured membranes, maternal fever, fetal distress, meconium-stained amniotic fluid, type of delivery (vaginal or cesarean section), anesthesia and analgesia used, reason for operative or forceps delivery, infant status at birth, resuscitative measures, and Apgar scores.

ASSESSMENT OF GROWTH & GESTATIONAL AGE

It is important to know the infant’s gestational age because normal behavior and possible medical problems can be predicted on this basis. The date of the last menstrual period is the best indicator of gestational age with early fetal ultrasound providing supporting information.

Commonly accepted definitions of term and preterm gestation are as follows:

• Term infants: delivery at or beyond 37 weeks; gestation

• Preterm infants: delivery before 37 weeks’ gestation

  • Late preterm infants: delivery between 34 and 37 weeks’ gestation

  • Extremely preterm infant: delivery before 28 weeks’ gestation

Postnatal physical characteristics and neurologic development are also clues to gestational age. The Ballard examination uses ...