The Clinical Approach to the Jaundiced Newborn



The Clinical Approach to the Jaundiced Newborn





Epidemiology of Neonatal Hyperbilirubinemia

An important first step in the diagnosis and manaWgement of any jaundiced newborn is an understanding of the factors that normally affect neonatal bilirubin levels (Table 35-13). Some of these factors have been identified only in large epidemiologic studies and their clinical relevance is questionable, but there are some (designated by asterisks in Table 35-13) that repeatedly have an important influence on TSB levels.


Genetic, Ethnic, and Familial Influences

East Asian and Native American infants have mean maximal TSB concentrations that are significantly higher than those of white infants (196,197,198,199,200 and 201). Increased bilirubin production appears to be one factor contributing to the hyperbilirubinemia in these infants (200). In a Hispanic (primarily Mexican) population, 31% of infants had TSB levels greater than 15 mg/dL (202) compared with 3% to 10% of infants in other populations (203,204). Black infants in the United States and Great Britain have lower TSB levels than white infants (197,198,205,206). Neonatal jaundice runs in families (207,208). In a study of 3,301 infants, Khoury and associates (207) found that if a previous sibling had a TSB level higher than 12 mg/dL (205 μmol/L) or higher than 15 mg/dL (257 μmol/L), the risk of similar TSB levels in subsequent siblings was 3.1 and 12.5 times greater, respectively, than in siblings of infants who did not have that degree of jaundice.








TABLE 35-13 EPIDEMIOLOGY OF NEONATAL JAUNDICE







































Associated Factors Effect on Neonatal Serum Bilirubin Levels
Increase Decrease No Effect
Race East Asian*
Native American
Greek
Hispanic (Mexican)*		 African American*  
Genetic or familial
Maternal		 Previous sibling with jaundice*
Primipara (?)
Maternal age ≥25 years
Diabetes (if infant macrosomic)
Hypertension
Oral contraceptive use at time of conception
First-trimester bleeding
Decreased plasma zinc level		  
Smoking
Drugs administered to mother Oxytocin
 
Diazepam
Epidural anesthesia
Promethazine		 Phenobarbital
 
Meperidine
Reserpine
Aspirin
Chloral hydrate
Heroin
Phenytoin
Antipyrine
Alcohol		 β-Adrenergic agents
Labor and delivery Premature rupture of membranes Fetal distress
Low Apgar scores
Infant Forceps delivery
Vacuum extraction*
Breech delivery
Decreasing gestation*
Male gender*
Delayed cord clamping
Elevated cord blood bilirubin level
Jaundice observed before discharge
Predischarge TSB level in higher risk zones (Fig. 35.20)
Cephalhematoma or bruising*
Delayed meconium passage
Breast-feeding*
Caloric deprivation*
Larger weight loss after birth*
Low serum zinc and magnesium		  
 
 
Gestation≥41 weeks* 
 
 
 
 
 
 
 
 
 
 Formula feeding*
Drugs administered to infant Chloral hydrate
Other Pancuronium
Altitude
Short hospital stay after birth*
* Most relevant clinical factors.



Maternal Factors


Smoking

Some studies suggest that infants of mothers who smoke during pregnancy have lower serum bilirubin levels than infants of nonsmokers (197,209), but others have not found this (210,211). These data are confounded by the fact that women who smoke are much less likely to breast-feed, and the likelihood of breast-feeding is inversely related to the number of cigarettes smoked per day (212).


Diabetes

Macrosomic infants of insulin-dependent diabetic mothers are more likely to become jaundiced than are control
infants (213). This most likely is the result of an increase in bilirubin production, which is directly related to the degree of macrosomia in these infants (214). These infants have high erythropoietin levels and evidence of increased erythropoiesis, so that ineffective erythropoiesis and polycythemia probably are responsible for the increased bilirubin production (215,216). In addition, diabetic mothers have three times more β-glucuronidase in their breast milk than nondiabetic mothers (216). This enzyme enhances the enterohepatic reabsorption of bilirubin (see Breast-Feeding and Jaundice below).


Events During Labor and Delivery


Induction and Augmentation of Labor by Oxytocin.

Multiple studies and several controlled trials have shown an association between the use of oxytocin to induce or augment labor and an increased incidence of neonatal hyperbilirubinemia, although the mechanism for this is unclear (217,218).


Anesthesia and Analgesia.

Several studies associate epidural anesthesia, specifically, bupivacaine, with neonatal jaundice (211,219,220). These agents readily cross the placenta and produce measurable levels in the new born (221).


Other Drugs.

Tocolytics did not affect neonatal carboxyhemoglobin levels or the need for phototherapy (222,223).

The administration of narcotic agents, barbiturates, aspirin, chloral hydrate, reserpine, and phenytoin sodium to mothers was associated with lower TSB concentrations in their infants, whereas the use of diazepam increased TSB levels by less than 1 mg/dL (224). Antipyrine administered to the mother before delivery decreased TSB levels, and infants of heroin-addicted mothers have lower TSB levels (225). Phenobarbital, if given in sufficient doses to the mother, significantly lowers TSB levels during the first week (217,226).

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Jul 1, 2016 | Posted by in OBSTETRICS | Comments Off on The Clinical Approach to the Jaundiced Newborn

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