Failure to Thrive in a 4-Month-Old Nursing Infant

Abstract

Christine, a 4-month-old infant, is brought to the office for a health-supervision visit by her mother, a 30-year-old emergency department nurse. The mother, who is well known to the pediatrician to be a competent and attentive caregiver, appears uncharacteristically tired. They are accompanied by the 18-month-old and 4-year-old siblings because child care was unavailable, and her husband has been out of town on business for the last 5 weeks. When the pediatrician comments, “You look exhausted. It must be really tough to care for 3 young children,” the mother appears relieved that attention was given to her needs. She reports that she has not been getting much sleep because Christine wakes up for 2 or more evening feedings and the toddler is now awakening at night. During the day, she juggles nursing the baby, caring for her other 2 young children, and managing the household. Although visibly fatigued and mildly depressed, the mother appears comfortable holding Christine; the baby likewise appeared closely attached. The mother has no concerns regarding Christine's health or development. During the physical examination, Christine is a slightly thin but active and alert infant. She has no remarkable or focal physical findings; her muscle strength, tone, and reflexes are normal. She achieves all motor, social, and language milestones for a 4-month-old infant. Plotting her height and weight on the growth chart, the pediatrician and mother were surprised to see that her weight did not change in 2 months, and her linear growth decelerated slightly. The growth measurements were repeated and corroborated. In the office, Christine was a vigorous feeder, latching onto the full areola quickly. During the nursing session, she studies her mother's face, cooed, and reached out for the breast with her free hand. The mother reports that breastfeeding occurs every 4 to 5 hours for …