premature infant

infant /in·fant/ (in´fint) the human young from the time of birth to one year of age.

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dysmature infant  postmature i.

floppy infant  see under syndrome.

immature infant  one usually weighing less than 2500 grams at birth and not physiologically well developed.

low birth weight (LBW) infant  one weighing less than 2500 g at birth.

mature infant  one weighing 2500 g or more at birth, usually at or near full term, physiologically fully developed, and having optimal chance of survival.

moderately low birth weight (MLBW) infant  one weighing at least 1500 but less than 2500 g at birth.

newborn infant  the human young during the first four weeks after birth.

postmature infant 

1. one with postmaturity syndrome.

2. postterm i.

postterm infant  one born at or after the forty-second completed week (294 days) of gestation.

premature infant 

1. one usually born after the twentieth completed week and before full term, defined as weighing 500 to 2499 g at birth; the chance of survival depends on the weight. In countries where adults are smaller than in the United States, the upper limit may be lower.

2. preterm i.

preterm infant  one born before the thirty-seventh completed week (259 days) of gestation.

term infant  one born in the interval from the thirty-seventh completed week to the forty-second completed week of gestation; 259 days to 293 days, inclusive.

very low birth weight (VLBW) infant  one weighing less than 1500 g at birth.

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premature infant,

any neonate, regardless of birth weight, born before 37 weeks of gestation. Because exact gestational age is often difficult to determine, low birth weight is a significant criterion for identifying the high-risk infant with incomplete organ system development. Predisposing factors associated with prematurity include multiple pregnancy, toxemia, chronic disease, acute infection, sensitization to blood incompatibility, any severe trauma that may interfere with normal fetal development, substance abuse, and teenage pregnancy. In most instances the cause is unknown. The incidence of prematurity is highest among women from low socioeconomic circumstances, for whom poor nutrition and lack of prenatal medical care are often precipitating factors. The premature infant usually appears small and scrawny, with a large head in relation to body size, and weighs less than 2500 g. The skin is thin, smooth, shiny, and translucent, with the underlying vessels clearly visible. The arms and legs are extended, not flexed, as in the full-term infant. There is little subcutaneous fat, sparse hair, few creases on the soles and palms, and poorly developed ear cartilage. In boys the scrotum has few rugae, and the testes may be undescended. In girls the labia gape and the clitoris is prominent. Among the common problems of the premature infant are variations in thermoregulation, chilling, apnea, respiratory distress, sepsis, poor sucking and swallowing reflexes, small stomach capacity, lowered tolerance of the alimentary tract that may lead to necrotizing enterocolitis, immature renal function, hepatic dysfunction often associated with hyperbilirubinemia, incomplete enzyme systems, and susceptibility to various metabolic upsets, such as hypoglycemia, hyperglycemia, and hypocalcemia. The degree of complications and the rate of survival of premature infants are directly related to the state of physiologic and anatomic maturity of the various organ systems at the time of birth, the condition of the infant other than prematurity, and the quality of postnatal care. With treatment in a neonatal intensive care unit, survival rates improve yearly. In increasing numbers of very small babies, development is normal, and those who do not have seizures or apneic spells in the first few days are unlikely to suffer neurologic or physical sequelae of their prematurity. Of primary concern for the nurse caring for the premature infant are the stabilization of body temperature by maintaining a neutral thermal environment, the maintenance of respiration, the prevention of infection, the provision of adequate nutrition and hydration, and the conservation of energy. Important functions of the nurse are to involve the parents in the care of the infant, to explain therapeutic procedures, and to facilitate attachment between the infant and family. Also called

Usage notes: (informal)

preemie, preterm infant. Compare postmature infant.

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premature infant

Prematurity, premie; preterm infant Obstetrics An infant born before the 37^th wk of gestation and after the 20^th wk, who weighs 500–2500 g. See Very-low birth weight.