Care of the Term Infant

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Chapter 1

Care of the Term Infant

The World Health Organization (WHO) defines a term infant as one who is greater than 37 weeks’ gestation. Recent evidence, however, has demonstrated that infants born at 37 weeks’ gestation behave differently from infants delivered at 39 and 40 weeks’ gestation. The more mature term infant (39 or 40 weeks) has fewer respiratory problems, less difficulty with feeding and hyperbilirubinemia, reduced birth injury, a greater ability to respond to infection, and an overall reduction in rates of neonatal complications.

Given that infants born before 37 weeks have even greater liability for problems, the recognition that true term status begins at about 39 weeks’ gestation has led the American College of Obstetrics and Gynecology (ACOG) and the American Academy of Pediatrics (AAP) to recommend that no infants be delivered electively before 39 weeks. ∗†

The mean birth weight of a term infant is approximately 3400 grams, or approximately 7 pounds, 7 ½ ounces. Mean length, which is sometimes difficult to measure accurately, is approximately 52 to 53 centimeters, or 20 inches, and head circumference averages 34 centimeters, or approximately 13.5 inches. Of note is the fact that birth weight in recent years has declined slightly, even though premature births have been declining. ∗

Approximately 10% of all infants need some assistance at birth (e.g., stimulation, oxygen), and approximately 1% need extensive assistance (e.g., positive pressure ventilation, fluids, drugs) at the time of birth. ∗

The Apgar score is a clinical assessment developed by Dr. Virginia Apgar at Columbia University during the early 1950s. Dr. Apgar was a great pioneer for women in medicine, and her development of the Apgar score is just one of her many landmark contributions to medicine. Although she was an anesthesiologist, she was very concerned about the status of newborn infants immediately after delivery. Her score, which was designed to evaluate both the immediate and long-term well-being of a neonate, has been reassessed periodically and still appears to be as valid today as when it was first introduced.

The Apgar score is determined at 1 and 5 minutes of life and consists of the measures listed in Table 1-1. These measures are scored 0, 1, or 2, then totaled.

TABLE 1-1

THE APGAR SCORE

image

It is rare for an infant to have an Apgar score of 10 (the highest possible score) in the absence of oxygen administration because the exposure of most newborn infants to the environmental temperature of the delivery room will cause some acrocyanosis of the hands and feet, reducing the potential score to 9. An Apgar score above 7 is considered good, one between 4 and 7 demands close observation, and one that is 3 or lower usually requires some intervention. Even with the changes that have occurred in modern medicine, the Apgar score has retained its value. ∗

One of the other important aspects of the Apgar score is the change between 1 and 5 minutes of life. For vigorous term infants the Apgar score does not change significantly between 1 and 5 minutes of life. Changes in the Apgar score, however, are useful for assessing the response to resuscitation. For example, a newborn infant who has a 1-minute Apgar score of 3 and a 5-minute score of 8 has probably had some terminal difficulty at the time of delivery that has been quickly surmounted. On the other hand, the neonate with Apgar scores of 3 and 4 at 1 and 5 minutes is not responding well and may need further intervention. When an infant’s 5-minute score is 5 or lower, it has become customary to continue to provide Apgar scores every 5 minutes up to 20 minutes of life or until the score is above 7. Slow improvement in an Apgar score may be associated with some element of hypoxia or ischemia during the delivery, but there are many other reasons for low Apgar scores. A low Apgar score at 1 or 5 minutes has a poor positive predictive accuracy for later disabilities.

When called to the delivery of a term infant, the clinician should first make sure that all possible tools that might be needed for resuscitation and maintenance of a thermal neutral environment are ready. Although the great majority of term infants in an uncomplicated pregnancy do not require any intervention, it is important to be prepared for any possibility. In addition, a number of other routine items are necessary. On arrival in the delivery room the following items should be checked:

image The radiant warmer should be turned on, and a temperature probe that can be attached to the skin should be available.

image Several dry towels and blankets should be heated under the radiant warmer for the infant.

image A resuscitation bag or a T-piece device should be available with masks of several sizes. If the gestational age of the infant is known, the most appropriate mask size can be chosen (typically a size 1 for term infants).

image An oxygen source should be available. In most instances resuscitation with 21% oxygen can be used initially if respiratory intervention is required.

image A laryngoscope and endotracheal (ET) tubes should be available. For the term infant, a 0 or 1 laryngoscope blade is appropriate, and a 3.5 FR ET tube should be used. Note: Although it may be easier to insert a smaller ET tube, this approach ignores the fact that work of breathing will be dramatically increased with a tube that is too small for the size of the infant.

image Umbilical catheters, size 3.5 and 5 FR, should be available along with D10W fluid and lactated Ringer’s solution. Feeding tubes should also be available for insertion into the stomach to drain the contents or air.

image A pulse oximeter should be available. In term infants needing resuscitation, the pulse oximeter provides valuable information (heart rate and oxygen saturation levels) regarding whether the interventions are succeeding.

image A medication box should be present with all medications that might be necessary for resuscitation of a neonate. Although the use of medications such as bicarbonate and calcium have fallen out of favor, there are unique situations in which these solutions may be needed as well as pressor drugs, such as epinephrine, Prostaglandin E1 for ductal dilation, and narcotic antagonists such as naloxone. Rarely are any other medications required in the delivery room.

image Suction for the removal of meconium and the emptying of stomach contents must be present.

image An umbilical cord clamp and scissors should be on hand.

image Erythromycin eye ointment should be present for prevention of gonococcal ophthalmia.

image Vitamin K1 for the prevention of vitamin K–dependent hemorrhagic disease of the newborn should be on hand.

Immediately before delivery the fetus is bathed in amniotic fluid and maintained at a temperature identical to that of the mother. Within seconds after birth, however, the neonate is exposed to a temperature drop of approximately 10° C. The fluid bathing the skin starts to evaporate, further depressing body temperature. Exposure to cold stress initiates a metabolic response in which brown fat lining the vertebrae, the kidneys, and the adrenal gland is consumed. Metabolism of brown fat raises body temperature (the neonate does not have a developed shivering mechanism to accomplish an increase in body heat) but also leads to increased acid in the blood. Cooling may also increase pulmonary vascular resistance, resulting in hypoxemia and respiratory distress.

Similarly, excessive heat administration may produce the same kind of changes. Delivery room heat usually comes from keeping a baby under the radiant warmer for a period of time without a temperature probe. In such cases the warmer will continue to emanate heat because it is not being servo controlled to the skin. The increased metabolic rate from the heat exposure can also cause the infant to become tachypneic. In infants with perinatal depression and possible hypoxic ischemic encephalopathy, hyperthermia should be prevented because it may increase the risk of neurodevelopmental disability.

The thermal neutral environment is usually in the range of 36° to 37.5° C skin temperature. Both term and preterm infants suffer similarly when under environmental stress, but the large surface to body mass ratio of the premature infant exaggerates the adverse consequences ( Fig. 1-1).

image

Figure 1-1 McCall EM, Alderdice F, Halliday HL, et al. Interventions to prevent hypothermia at birth in preterm and/or low birthweight infants. Cochrane Database Syst Rev 2010 Mar 17;3:CD004210.

Assuming that the obstetrician has clamped the baby’s umbilical cord and the baby appears to be vigorous (i.e., the baby is crying, breathing, centrally pink), the infant should be brought immediately to the radiant warmer and dried thoroughly. A quick weight should be obtained once the baby is dry. All wet blankets and towels should be discarded and the infant clothed in a warmed diaper and dry top. A knit cap should be added to prevent loss of heat from the scalp.

Historically, one of the most important issues with regard to newborn infants was the possibility of developing gonococcal ophthalmia as a result of passing through the birth canal of a mother infected with Neisseria gonorrheae. Gonococcal ophthalmia can produce a severe purulent conjunctivitis that may result in permanent loss of vision and generalized neonatal sepsis. The eye discharge resulting from this infection typically begins during the first 5 days of life.

Eye prophylaxis previously consisted of treatment with silver nitrate drops to the eyes. However, silver nitrate itself causes a significant, though temporary, chemical conjunctivitis. In the past decade it has been replaced by the administration of antibiotic ointment, such as 1% tetracycline or 0.5% erythromycin in single-use ampules.

Neonatal conjunctivitis may be produced by a variety of infectious agents in addition to N. gonorrheae. Chlamydia trachomatis is now the most common form of neonatal conjunctivitis, occurring in approximately 0.5% to 2.5% of all term births in the United States. This infection typically appears between 3 days and 6 weeks of life with an eye discharge, which is occasionally accompanied by pneumonia (10% to 20% of patients). The agents used to prevent N. gonorrheae infection do not prevent chlamydial conjunctivitis.

Other infectious agents capable of causing an eye infection in the newborn infant include Staphylococcus, Group A and B Streptococcus, Pneumococcus, Pseudomonas aeruginosa, and herpes simplex virus. ∗

The use of footprints has been a tradition in hospitals for decades and is mandated in most states. Although the value of footprinting is debatable and the manner in which footprints are obtained is often haphazard, footprints occasionally prove valuable if the identity of the infant in the hospital is in question. Footprinting ideally should be done as soon as possible after delivery, but it can be deferred if the infant develops signs of disease that require intervention or if immediate maternal contact is desired. Footprints should be obtained before the child leaves the delivery room area. The long-term value of footprints is essentially negligible beyond the immediate neonatal period. More sophisticated methods to identify infants using DNA are coming into use.

Studies from a number of investigators in recent years have contradicted the traditional concept that babies become well saturated within a few breaths after birth. In fact, the transition usually requires between 10 and 12 minutes, or longer occasionally, before a term infant’s saturation reaches approximately 93% to 95% ( Fig. 1-2).

For many years babies with congenital heart disease arrived in the delivery room with no prenatal diagnosis. Such infants commonly presented with severe cyanosis and respiratory distress, often beginning within minutes of birth. With the introduction of antenatal ultrasound screening during the early 1980s, the number of babies who were born undiagnosed dropped dramatically. It was evident, however, that some critical cardiac diagnoses could be overlooked on ultrasound examination and not manifest until some time later (even after hospital discharge of the infant), placing the baby at some jeopardy. Ductal-dependent lesions, in which the systemic circulation is oxygenated through blood flowing through a patent ductus arteriosus, may result in sudden cardiovascular collapse in affected infants as the ductus closes, with a risk of death. Lesions that can provoke this sudden deterioration include coarctation of the aorta, hypoplastic left heart syndrome, aortic stenosis, and transposition of the great vessels.

Oxygen saturation screening, in which oxygen saturation is less than 95% on day 2 of life, has been demonstrated to identify many of the infants who are not diagnosed during physical examination. Because of the apparent value of this screening, in 2011 the Secretary of Health and Human Services, Kathleen Sebelius, recommended the use of oxygen saturation screening in newborn infants before hospital discharge. ∗†

A number of infants will not consistently demonstrate saturation levels at 95% or above in the 2 days before discharge from the nursery for a variety of reasons, most of which are not reflective of congenital heart disease. Preliminary data collected by Pediatrix Medical Group suggest that approximately 0.5% of all infants will fail initial screening. According to some observations, infants born at higher altitudes (>4000 feet) appear to have a false-positive rate of nearly 50% during initial screening. All infants who screen positive should be followed up with the currently recommended cardiac echocardiogram. This requirement presents substantial difficulties for many nurseries. In addition, many of the community hospitals around the country that offer maternity services do not have ready access to a cardiologist who can perform this study. It may become necessary to modify the screening procedure in the near future to prevent a prohibitive increase in the cost of care. ∗

The introduction of feedings has undergone significant changes during the past several decades. During the mid-1900s, it was thought that early feeding was not a good idea, and many neonates were not placed at the breast or approached with a bottle for 8 to 12 hours after birth. The sudden removal of a continuous source of nutrients from the placenta (especially glucose) during this time placed some neonates at risk for hypoglycemia. In fact, the definition of hypoglycemia has itself changed in recent years as the long-term outcome of hypoglycemic infants has become more of a concern. Few physicians would now consider a blood glucose level below 40 mg/dL acceptable for a term neonate, whereas it was not uncommon to see infants’ blood glucose levels at 30 to 40 mg/dL several decades ago in the early hours after delivery. To promote successful breastfeeding, the AAP and the WHO have recommended that breastfeeding be initiated within the first hour after birth.

With the increased enthusiasm for breastfeeding of newborn infants, babies are often placed at the mother’s breast within minutes of delivery. Although mother’s milk is scanty at this time and it takes approximately 2 to 3 days for full milk flow to appear, the provision of the high fatty content of colostrum (the earliest milk that is secreted from the breast), together with the immunoprotective characteristics (e.g., white blood cells, antibodies) of colostrum, appears to be very advantageous for newborns and greatly reduces the incidence of hypoglycemia. ∗

Although breastfeeding is clearly best, it is not always possible. Infants with galactosemia should not nurse; instead, they must be fed a lactose-free formula. In the United States mothers with human immundeficiency virus (HIV) should also not nurse or provide expressed milk because they may pass on the virus to the infant. Mothers with active untreated tuberculosis or active herpes simplex lesions on the breast should also not breastfeed, but they may use expressed milk because these organisms are not transmitted through the milk. Mothers who require antimetabolites or chemotherapy should not breastfeed as long as they are receiving those medications. Radioactive materials acquired during the performance of a medical study are temporary contraindications to nursing. Whereas most drugs are secreted into breast milk, they rarely form an absolute contraindication to nursing. Drug effects, however, should be carefully checked using a reliable resource to ensure that the infant is not unnecessarily exposed to a potentially hazardous medication. ∗†‡

Manufacturers of formula have long established that infants grow quite satisfactorily on any of the commercially available infant formulas. Nevertheless, it is evident that breast milk and formula are different in terms of their appearance and their composition. The most striking difference is the immunoprotective aspect of breast milk, which contains white cells and antibodies that appear to be quite valuable in preventing neonatal infections of a variety of types, especially in the respiratory system and the gastrointestinal tract. ∗

It is difficult to state these differences precisely because breast milk is not a fixed entity. A mother’s milk is said to “mature” over the course of the first weeks of an infant’s life, with the composition changing to some degree during that period. Furthermore, breast milk changes even during the course of a single feeding between what is referred to as the foremilk (the early part of a feeding) and the hindmilk (the later part of a feeding). The gradual and progressive transition to hindmilk during a feed results in a higher fatty content, which aids in allowing the infant to feel satiated and initiates the termination of feeding. Over the first weeks of an infant’s life, breast milk caloric density usually drops from approximately 20 to 25 calories per ounce on average to approximately 15 to 17 calories per ounce. In addition, levels of sodium and calcium decline.

Variations in the composition of breast milk among individual mothers can be quite dramatic. Some women will have relatively modest fat content in their milk, resulting in a caloric content as low as 9 to 10 calories per ounce. In contrast, other mothers produce rich, creamy breast milk, with a high fat content and a caloric density that may reach 30 calories per ounce. ∗

The concept of bioavailability, or the capacity to extract nutrients from food sources, is an important one. Because the composition of breast milk and that of formula differ, it is essential that the food substances, minerals, and vitamins in formula are accessible so that they can be utilized by the neonate. It has been shown that some important minerals (e.g., iron [Fe]) are not as bioavailable in formula as they are in breast milk. Term infants fed only breast milk beyond 6 months will rarely show evidence of iron deficiency anemia, even though the iron content of breast milk is lower than that of iron-fortified formula (0.3 mg/L versus approximately 12 mg/L).

Similarly, protein in breast milk is more bioavailable than protein in formula, and the concentration of protein in formula is correspondingly higher than the amount of protein in breast milk (formula contains approximately 2 to 2.1 g protein/100 kcal versus 1.5 g protein/100 kcal of breast milk). Similar differences between formula and breast milk exist for other vitamins and minerals, as well, to overcome the reduced bioavailability in formula.

Breast milk is composed of approximately 60% whey (lactalbumin) protein and 40% casein. Formula is generally 80% casein and 20% lactalbumin.

When a mother first gets her milk supply, her breasts will feel significantly engorged, usually beginning on the second day after delivery. Placing the infant to the breast will allow the expression of the let-down reflex at this time. This response results in the formation of milk droplets on the nipple opposite from the the breast at which the baby is nursing. When this response occurs, the milk supply is usually considered adequate.

Although most term neonates take to nursing right away, some are a bit slower to master the technique. In addition, the nipple needs to be toughened gradually so that the mother does not experience any discomfort while nursing. Therefore the duration of nursing should be limited to 5 minutes at one breast before the infant nurses from the other breast. Many babies will initially need some encouragement to keep nursing because they fall asleep early in the feeding. A little bit of stimulation, such as gently rubbing the shoulders or face, or repositioning the infant will usually be adequate to prompt the baby to resume nursing. Because newborns are “demand” feeders, feeding intervals are often irregular. Ideally, in the first few days a newborn should have between 8 and 12 feedings per day. Once the milk supply is well established, the infant usually will gain interest in feeding. As that occurs, the time spent on each breast can be progressively increased, although a maximum of approximately 10 minutes is generally a good idea during the first 2 weeks of nursing. After that time, mother and infant usually develop a comfortable pattern that no longer calls for watching the clock.

Once a mother has established a solid breast milk supply, an infant will meet the bulk of its nutritional and fluid needs (>90%) within 10 minutes of nursing. It is important, however, that a mother empty her breasts regularly on both sides to reduce the risk of cracking of the nipples and mastitis. If the infant nurses on one side and then falls asleep, the mother should try to awaken the baby and place the baby on the other breast for some time, although the added nutrition will be modest.

In general, neonates regulate their intake needs quite well, and if the baby cannot be aroused with gentle stimulation, he or she is probably satiated. For comfort, however, the mother might elect to use a breast pump to express some milk from the side that has not been nursed. That milk can be saved and refrigerated in a clean bottle, allowing the father to get up in the middle of the night and share in the feeding responsibilities.

There is little question that breast milk suffices for the overwhelming majority of infants. Nearly all infants will grow and gain weight well at 3 months of age even when fed milk from a mother who produces very low-fat, watery breast milk. Solid foods and cereals need not be introduced into the infant’s diet until a minimum of 4 to 6 months of age.

Many neonates, both from a nutritional and a comfort perspective, derive great pleasure from nursing. As a result, they often become avid feeders and want to nurse around the clock. This behavior may be especially true for infants whose mothers have breast milk with lower fat content because these babies need to nurse more often to feel satiated. For those mothers, however, the joy of nursing soon gives way to chronic fatigue caused by awakening throughout the night to nurse.

During the daytime the interval between feedings should be lengthened progressively by simply distracting the infant. Talking to the baby, allowing the baby to watch the mother working around the house, reading simple stories to the baby, and so forth will often buy an additional hour or so between feedings. This timing change will usually form a new behavioral pattern that is less taxing for the mother. Expressing breast milk so that the father can participate in feeding is an ideal and obvious means of reducing the constant demands placed on the mother. The pediatrician should monitor the baby’s weight to ensure that the increased intervals between feedings do not adversely affect the infant. They rarely do.

The umbilical cord usually takes approximately 10 to 14 days to separate and fall off. Infants whose cords remain on longer may, in rare cases, have an immune deficiency that interferes with and delays this process. Until it falls off, the umbilical cord should simply be kept clean. In the past parents were told to clean the cord with alcohol frequently, but some evidence suggests that this may actually delay cord separation and offers no real advantage. Therefore the cord should be gently cleaned with warm water once or twice a day. Diapers should be folded down below the cord level so that the rough cord edges do not irritate or scrape the periumbilical area. If the cord becomes contaminated with urine or stool, it should be washed carefully with warm water and then dried well. Parents should avoid the tendency to pull the cord off, even when it appears to be hanging by a thin thread because doing so may result in omphalitis. ∗

In the majority of cases, continued oozing from an umbilical cord is caused by an umbilical granuloma ( Fig. 1-3).

The granuloma represents a cord remnant but does not appear to be associated with any known disease states. It is pinkish-white and secretes a thin, watery mucous discharge. It is easily treated by application of silver nitrate to the granuloma. It is important to avoid the surrounding umbilical area when applying the silver nitrate.

Caution should be exercised when examining the umbilicus to ensure that no other conditions exist that may affect the infant’s well-being. A patent urachus—a connection between the umbilicus and the bladder—may secrete urine in the area. An omphalomesenteric sinus—a connection between the umbilicus and the bowel—may secrete stool though the umbilicus. Some infants may also have a small omphalocele in the area, and this should not be cauterized. All these lesions require surgical intervention.

Omphalitis is cellulitis of the umbilicus or periumbilical area. It is marked by a red, indurated area around the umbilicus; fever; irritability; and a generally ill-appearing neonate. It typically appears during the latter part of the first or second week of life, just before cord separation. In addition to generalized sepsis, the greatest risk to the infant is spread to the abdominal fascial plane or penetration into the connecting vascular system (causing portal vein thrombosis). Omphalitis can be life-threatening and is usually caused by gram-positive organisms, especially Staphylococcus aureus.∗

As previously noted, omphalitis is a cellulitis of the periumbilical area that begins after birth. Funisitis is an infection of the umbilical cord tissue itself that typically begins in utero and is often associated with chorioamnionitis. Both the umbilical vessels and Wharton jelly of the cord may be involved in funisitis.

Circumcision refers to the removal of the foreskin of the penis. The most recent recommendations of the AAP state that “the preventive health benefits of elective circumcision of newborn males outweigh the risks of this procedure. Benefits include significant reductions in the risk of urinary tract infection in the first year of life and, subsequently, in the heterosexual risk of HIV and other sexually transmitted infections. Although health benefits are not great enough to recommend routine circumcision for all newborn males, the benefits of circumcision are sufficient to justify access to this procedure for families choosing it and to warrant third-party payment for circumcision of newborn males.” (Guidelines for Perinatal Care, 7th Edition, 2012, American Academy of Pediatrics, and the American College of Obstetrics and Gynecology, p.  286). Ritual circumcision is part of a number of religions, and cultural differences should be respected. ∗

All infants are exposed to the mother’s circulating hormones in utero, especially progesterone. In female infants the withdrawal of those hormones from the infant’s circulation leads to a shedding of the immature uterine lining and a form of temporary menses, which, although often frightening to the parents, is completely benign.

A related phenomenon, referred to as “witch’s milk,” may also occur. This is a milky discharge from the infant’s nipples during the first days of life, again related to high levels of circulating hormones transferred from the mother’s circulation.

If you practice pediatric medicine for any length of time, you have received a call from a nurse informing you that a baby has not voided for ____ hours (the number of hours varies). The problem with voiding in the neonatal period is that it is a complex phenomenon that depends on fluid volume at the time of birth and a variety of other factors, many of which are not easily measurable. Furthermore, it is not uncommon for an infant to void in the delivery room without anyone noticing. As a result, many newborn infants will not void during the first 24 hours of life. If a baby goes beyond 24 hours without voiding, however, it is reasonable to determine why the infant is failing to pass urine. As a first step, the clinician should attempt to palpate the bladder. If the bladder is obstructed (the posterior urethral valves in a male infant is the most common site), the bladder will be easily felt and sometimes observed as a bulge above the symphysis pubis. If there is a concern about a urinary tract anomaly or renal failure, laboratory studies (blood urea nitrogen, creatinine, and electrolyte concentrations) and an ultrasound of the urinary tract should be obtained. The management of neonates with suspected renal failure is complex and should always include consultation with a pediatric nephrologist and, when appropriate, a urologist.

There is essentially no such thing as a “normal” stool pattern in healthy term neonates. As with voiding, many infants will not pass an initial stool for a day or more.

The first several bowel movements consist of a tenacious black, tarry substance called meconium. Meconium comprises swallowed amniotic fluid, desquamated intestinal cells, and digestive enzymes. After the first few passages of meconium, the stool begins to change, as does the nature of the bowel movements, depending on the diet of the infant. The breastfed infant often has stools that become golden yellow, then yellow-green. They are fairly soft and occasionally become watery. These stools generally have little odor. In contrast, the formula-fed infant will have more solidly formed stools that are significantly harder and more odorous.

Breastfed infants may pass stool up to eight times daily with each feeding and be perfectly well. The formula-fed infant generally passes stool only once or twice a day, although they may do so more frequently on occasion.

Few products represent as much of a dilemma as disposable diapers. How mankind managed to survive without them for millions of years is difficult to imagine. Many parents today would never think of going out of the house without them. However, the plastics used in their manufacture are not biodegradable and are considered harmful to the environment. Cloth diapers are an acceptable alternative to disposable diapers and are available through diaper services in most communities. The cost is often less or comparable to that of disposable diapers. For the environmentally conscious family, the cloth diaper is preferable to the constant use of disposables.

Neonatal metabolic screening represents one of the most important changes in the care of the newborn infant during the past several decades. Starting with the initial metabolic defect of phenylketonuria (PKU), an increasing number of abnormalities can now be detected shortly after birth. During the 1950s it was recognized that infants with PKU could be treated effectively with dietary restriction that resulted in a normal outcome if the disease could be picked up early in life. Guthrie then developed a bacterial inhibition test (the Guthrie assay) for the detection of PKU. Beginning in 1961 states began to adopt newborn screening for PKU, which was soon followed by tests to detect congenital hypothyroidism. Additional tests were added by many states in their screening programs until the implementation of tandem mass screening technology during the past decade replaced most of these individual tests with a single test performed on a dried blood spot on filter paper. All 50 states now mandate screening for certain genetic and metabolic diseases.

There are three primary goals that otherwise healthy infants must meet to be discharged from the hospital after birth: (1) the ability to feed adequately; (2) the ability to maintain body temperature in a room air temperature environment; and (3) absence of any cardiorespiratory abnormality that may place an infant at risk. The infant must also have passed stool and voided. Although the preceding goals are relatively easy for the term infant to meet, a variety of common issues may delay discharge. These include hyperbilirubinemia, hypoglycemia, suspected septicemia, infant apnea, anemia, and signs of substance withdrawal. Because many of these topics are discussed in depth elsewhere in this book, they will not be presented in detail here. Although parents whose infants cannot be discharged at 48 hours are often greatly distressed, a clear and sympathetic explanation of the reasons this is necessary usually alleviates their concerns. Providing a comfortable place for the mother to visit during the delayed discharge should also be a high priority of care.

The typical in utero position of a fetus is with the head placed towards the cervix and the legs positioned towards the fundus. Most commonly, the legs are flexed and crossed most of the time, with the tibia overlying one another. The feet may also tuck into the creases created by the leg flexion, and this position, depending on the site of placental implantation, may place some pressure on the tibia as the fetus matures. It is often interesting to try to flex the newborn’s legs into the “position of comfort,” or the position in which the neonate spent most of its time before birth. As a result, the tibia often turns in slightly, which is referred to as tibial torsion. This toeing-in from the tibial torsion usually disappears soon after the child starts to walk, and very few children are left pigeon-toed. As the feet can be brought to a neutral midline position, no intervention is usually necessary.

After an initial period of weight loss, primarily caused by the loss of the excess extracellular fluid that is present at birth, the infant will begin to gain weight toward the middle to end of the first week of life and should attain birth weight no later than 2 weeks after delivery. Weight gain usually approximates intrauterine weight gain and averages about 1 ounce (30 grams) per day. Weight gain begins to slow down at approximately 5 to 6 weeks of age. A commonly cited rule of thumb is that an infant’s birth weight should double at 4 to 5 months of life and triple at approximately 1 year of age. However, the variability among completely normal children can be significant.

Although breast milk is the best nutritive substance for infants, studies have demonstrated a high incidence of deficient vitamin D levels in breastfed infants. Breast milk can be low in vitamin D as a result of a lack of maternal sun exposure (particularly in the winter and in northern latitudes), increased use of sunscreen, and dress habits that prevent skin exposure. The AAP recommends that any breastfeeding infant be given 400 IU of vitamin D daily beginning within a few days of life. In breastfed infants who are receiving supplemental formula, vitamin D supplementation should still be provided unless the infant is consuming 1 liter of formula per day (the amount needed to provide 400 IU). ∗

Pacifier use has previously been discouraged in breastfed infants because studies have demonstrated an association with less successful breastfeeding. However, pacifier use has also been shown to be associated with a reduction in the incidence of sudden infant death syndrome (SIDS). Thus it is now recommended that all formula-fed infants be given a pacifier at nap or at bedtime. For breastfeeding infants the use of a pacifier is also recommended at bedtime, but its use should not begin until breastfeeding has been well-established, which is typically 3 to 4 weeks after birth. ∗†

∗American Academy of Pediatrics and the American College of Obstetricians and Gynecologists. Guidelines for perinatal care, 6th ed. Elk Grove Village, IL and Washington, DC: AAP and ACOG; 2007.

†Clark S, Miller D, Belfort M, et al. Neonatal and maternal outcomes associated with elective delivery. Am J Obstet Gynecol 2009;200:156.e1-156.e4.

∗Donahue SM, Kleinman KP, Gillman MW, et al.Trends in birth weight and gestational length among singleton term births in the United States. 1990–2005. Obstet Gynecol 2010 Feb;115(2 Pt 1):357–64.

∗American Academy of Pediatrics, The American College of Obstetrics and Gynecology. Care of the neonate in guidelines for perinatal care, 6th ed. 2007;205.

∗Finster M, Wood M. The Apgar score has survived the test of time. Anesthesiology. 2005 Apr;102(4):855–7.

∗Zuppa AA, D’Andrea V, Catenazzi P, et al. Ophthalmia neonatorum: what kind of prophylaxis? J Matern Fetal Neonatal Med 2011 Jun;24(6):769–73.

∗Bradshaw EA, Martin GR. Screening for critical congenital heart disease: advancing detection in the newborn. Curr Opin Pediatr 2012 Oct;24(5):603–8.

†Mahle WT, Martin GR, Beekman RH 3rd, et al. Section on Cardiology and Cardiac Surgery Executive Committee. Endorsement of Health and Human Services recommendation for pulse oximetry screening for critical congenital heart disease. Pediatrics 2012 Jan;129(1):190–2.

∗Bradshaw EA, Cuzzi S, Kiernan SC, et al. Feasibility of implementing pulse oximetry screening for congenital heart disease in a community hospital. J Perinatol 2012;32:710–5.

∗Eidelman AI, Schanler RJ. American Academy of Pediatrics Section on Breastfeeding. Breastfeeding and the use of human milk. Pediatrics 2012;129:e834.

∗Eidelman AI, Schanler RJ. American Academy of Pediatrics Section on Breastfeeding. Breastfeeding and the use of human milk. Pediatrics 2012;129:e832.

†Schaefer C, Peters PWJ, Miller RK. Drugs during pregnancy and lactation: treatment options and risk assessment, 2nd ed. London: Academic Press; 2007.

‡Weiner CP, Buhimschi C. Drugs for pregnant and lactating women. Philadelphia: Saunders; 2009.

∗Hurley WL, Theil PK. Perspectives on immunoglobulins in colostrum and milk. Nutrients 2011;3:442–74.

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