postmature infant

Also found in: Dictionary, Thesaurus, Legal, Encyclopedia.


a human child from birth (see newborn infant) to the end of the first year of life. Emotional and physical needs at this time include love and security, a sense of trust, warmth and comfort, feeding, and sucking pleasure.
Growth and Development. Development is a continuous process, and each child progresses at his own rate. There is a developmental sequence, which means that the changes leading to maturity are specific and orderly. The various types of growth and development and the accompanying changes in appearance and behavior are interrelated; that is, physical, emotional, social, and spiritual developments affect one another in the progress toward maturity.

Development of muscular control proceeds from the head downward (cephalocaudal development). The infant controls the head first and gradually acquires the ability to control the neck, then the arms, and finally the legs and feet. Movements are general and random at first, beginning with use of the larger muscles and progressing to specific smaller muscles, such as those needed to handle small objects. Factors that influence growth and development are hereditary traits, sex, environment, nationality and race, and physical makeup. See also growth.
large-for-gestational-age infant a preterm, term, or postterm infant who is above the 90th percentile for gestational age in head circumference, body weight, or length.
low-birth-weight infant one that weighs less than 2500 grams at birth. This standard is routinely used for infants in developed countries, but infants born in other countries typically weigh less at birth. In India the criterion for normal birth weight is 2150 grams and in Malaysia it is 2000 grams.
newborn infant a human infant from the time of birth through the 28th day of life. At birth, the gestational age as well as birth weight is assessed and the newborn classified accordingly; for example, large for gestational age, preterm (premature), or low birth weight. Called also neonate and newborn.
premature infant (preterm infant) one born before a gestational age of 37 completed weeks (259 days). The duration of gestation is measured from the first day of the last menstrual period and is expressed in completed days or weeks.
postmature infant (postterm infant) one born any time after the beginning of the forty-second week (288 days) of gestation.
small-for-gestational-age infant a preterm, term, or postterm infant who is below the 10th percentile for gestational age in head circumference, body weight, or length.
term infant one born at a gestational age of 37 to 42 completed weeks (259 to 293 completed days).
very-low-birth-weight infant one that weighs less than 1000 grams at birth.
Patient Care. Low-birth-weight and very-low-birth-weight infants require special care and support, preferably in a neonatal intensive care unit (NICU), until sufficient weight is gained and the infants have matured and are able to thrive without elaborate support systems.

At the time of delivery, whether cesarean or vaginal, a skilled neonatal team should be present to provide immediate care. After resuscitation measures under a radiant warmer are completed and the newborn is stabilized, transfer to the NICU is done without interruption of warming and oxygen therapies.

Among the problems associated with low birth weight are hypothermia, respiratory distress, hyperbilirubinemia, fluid and electrolyte imbalance, susceptibility to infection, and feeding problems.

Very-low-birth-weight newborns and infants are at significant risk for hypothermia because of their small body mass, large surface area, thin skin, minimal subcutaneous tissues, and posture. Thermoregulation is provided through the use of a standard incubator or a radiant warmer. Radiant warmers have the advantage of accessibility for caregivers and improved visibility of the infant. Their chief disadvantage is increased insensible water loss.

Neonatal respiratory distress syndrome is the major cause of death in newborns. Atelectasis can lead to hypoxemia and elevated serum carbon dioxide levels and all the problems related to inadequate gas exchange. Oxygen therapy must be administered with caution because of the danger of retinopathy.

The treatment of hyperbilirubinemia remains a challenge because of lack of consensus on the level of serum bilirubin concentration at which therapy should begin, the uncertain diagnosis of kernicterus, and the currently limited knowledge of the blood--brain barrier. It is believed that these infants are at critical risk for bilirubin-related brain damage at serum concentrations as low as 6 to 9 mg/dl. Phototherapy is the treatment of choice and may be given prophylactically in some institutions to all infants weighing less than 1000 grams.

The management of fluid and electrolyte administration to maintain proper balance is highly complex. Factors taken into consideration are proportion of body, composition of water, renal function, and insensible water loss. Fluid and electrolyte status must be closely monitored. Overhydration is a hazard because it has been implicated in the development of such serious complications as pulmonary edema, patent ductus arteriosus, and necrotizing enterocolitis in these infants.

Low-birth-weight and very-low-birth-weight infants are particularly susceptible to infection because their immunologic system is deficient. Additionally, equipment and care related to long-term respiratory and nutritional support, together with frequent laboratory testing, increase exposure to infectious agents. Infection control measures must be adhered to faithfully. In some NICUs reverse isolation is required for all infants weighing less than 1000 grams.

Since the skin of these infants is highly permeable and easily traumatized, every effort must be made to preserve its integrity. Routine care to preserve the integrity of the skin, caution in the use of topical ointments and antiseptic preparations, and minimal handling also are essential.

At the beginning, nutritional support in the form of total parenteral nutrition may be necessary until enteral feedings are feasible. Oral feedings usually are initiated by the end of the first week of life. Continuous gastric feedings via infusion pump have the advantage of preventing vomiting and aspiration and abdominal distention associated with intermittent feedings of larger amounts. The enteral feedings given in this manner include breast milk (donor or mother) and special formulas.

Discharge planning and follow-up care are begun upon admission to the NICU. Individual family needs should be assessed and available community resources identified. Parental education and support are provided throughout the time the infant is in the NICU. At the time of discharge parents should be confident of their ability to care for the infant, knowledgeable about sources available to them, and able to utilize those resources to the fullest.

post·ma·ture in·fant

a baby born after over 42 weeks of gestation, which puts the child at risk because of inadequate placental function. The infant usually shows wrinkled skin, and sometimes more serious abnormalities.

postmature infant

an infant born after the end of the 42nd week (288 days) of gestation, bearing the physical signs of placental insufficiency. Characteristically the baby has dry, peeling skin; long fingernails and toenails; and folds of skin on the thighs and sometimes on the arms and buttocks. Hypoglycemia and hypokalemia are common. Postmature infants often look as if they have lost weight in utero. The newborn is fed early, and the calcium and potassium levels in the blood are monitored and corrected, if necessary, to prevent seizures and neurological damage. To prevent the syndrome, labor may be induced as gestation approaches 42 weeks. To anticipate the problems associated with the syndrome, the fetus and the mother may be electronically monitored through labor. Also called postmature newborn, postterm infant.
enlarge picture
Dry skin of postmature infant


, postmature infant , postterm infant (pōst'mă-chŭr', in'fănt, pōst-tĕrm')
Referring to a fetus that remains in the uterus longer than the normal gestational period, i.e., longer than 42 weeks (288 days) in humans, which puts the child at risk because of inadequate placental function. The infant usually has wrinkled skin, and sometimes more serious abnormalities.