newborn infant
Noun | 1. | newborn infant - a baby from birth to four weeks |
单词 | newborn infant | |||
释义 | newborn infant
Newborn InfantNewborn Infantan infant less than a month old. The stages of development during the newborn period differ for full-term and premature infants. A full-term baby, who undergoes an intrauterine development of ten lunar months (40 weeks, or 280 days), has an average weight at birth of 3,200–3,500 g (from 2,500 to 4,500 g). The infant has an average length of 50 cm (47–54 cm) and an average head circumference of 32–34 cm. The age, physical development, and state of health of the parents, as well as the diet and work conditions of the mother during pregnancy, influence the weight and length of the newborn infant. The newborn period is characterized by a number of morphological and functional changes as a result of the transfer from intrauterine to extrauterine life. During the first days of life (up to four or five days) a physiological loss of weight (5 to 8 percent) occurs. A weight loss of more than 10 percent is considered pathological. Beginning on the seventh to the tenth day of life the weight is regained. During the first month of life the infant’s weight increases by 600 to 700 g. The body temperature in the first two to three weeks is unstable and greatly depends on the temperature of the environment. Twitching and slight trembling of the limbs, as well as grimacing, may occur in the first days of life. The newborn infant has characteristic congenital reflexes that disappear by the third or fourth month. The child distinctly reacts to light and to loud sounds, and the senses of smell and taste are developed. Sometimes a lowering of reflex activity and a decrease in muscle tone are observed during the first three days of life. This usually is due to the trauma of birth and disappears as a rule by the third to fifth day. Initially, the newborn child maintains a fetal position, with the limbs bent and held close to the trunk. The subcutaneous fat layer is distributed evenly, imparting to the infant roundness and fullness. The musculature is poorly developed, and the skin is thin and is easily injured. The head constitutes one-fourth to one-fifth of the body length. The trunk is longer than the legs, and the arms and legs are approximately the same length. The spine has no flexures. The ribs are attached to the spine at right angles, and the thorax is barrel-shaped. The large fontanel formed by the frontal and parietal bones remains open. Respiration is uneven in frequency and depth, with 40 to 60 respiratory movements per minute. The pulse is 120 to 140 beats per minute and, during crying, 160 to 200 beats per minute. The stomach is small in capacity and lies horizontally. The intestine is relatively long and has an underdeveloped nervous apparatus, a delicate mucous membrane, an abundance of blood vessels and villi, and weak muscle and elastic layers. There is some deficiency of the intestinal glands, and the intestinal wall has great permeability. There is little saliva, and the protective function of the oral mucosa is poorly developed. All the enzymes necessary for digestion are present: amylase, ptyalin, maltase, invertase, lipase, pepsin, cathepsin, rennin, erepsin, nuclease, enterokinase, and secretin. Hydrochloric acid in both free and bound states is found in the gastric juice. Microorganisms appear in the infant’s gastrointestinal tract and respiratory system just hours after birth. In the first two or three days of life, the first fecal matter, or meconium, is discharged. The discharge, a thick, viscous, odorless, olive-green mass, consists of mucus, bile, and desquamated epithelial cells. Later the bowels evacuate brownish green fecal matter, which is rich in mucus and sometimes is watery and foamy. On the fifth or sixth day, the normal stool, characterized by a sour odor, is established. In the first two days of life, the infant urinates four or five times per day. Beginning on the third day urination occurs more often, and, by the end of the second week, the child urinates 15 to 20 times per day. Water metabolism plays an extremely important role in the life of the newborn child. Water constitutes 75 to 80 percent of the infant’s weight but is not firmly bound in the body. Therefore, water balance is easily disrupted. The newborn child’s daily water requirement averages 160–200 g per kg of weight. REFERENCESSpravochnik pediatra. Moscow, 1966.Tur, A. F. Fiziologiia i patologiia novorozhdennykh detei, 4th ed. Leningrad, 1967. Molodym roditeliam, 2nd ed. Edited by V. A. Vlasov. Moscow, 1973. E. CH. NOVIKOVA newborn infantinfant[in´fant]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. 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. respiratory distress syndrome" >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. Patient discussion about newborn infantQ. Should I vaccinate my newborn against Hepatitis B? I am 9 months pregnant and am expecting to give birth anytime soon. I understood that my newborn will receive a vaccine against Hepatitis B in the hospital. Why is this so? Q. Is there a bigger risk of autism for the newborn in twin pregnancy? Q. I gave birth a short while ago, and since then I just can't stand my husband. is that normal? It's very strange, because we used to be such a great couple but since the baby came into our lives, I am tired all the time, and basicaaly every thing he does gets me so annoyed. Could it be the hormones? will we get back to how we used to?(This is a great site - I feel I can finally ask questions I was too ashamed to ask my family and friends :) newborn infant
Synonyms for newborn infant
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