Jenny Thomas, MD, MPH, IBCLC, FAAP, FABM Pediatrician, Aurora Health Care Clinical Assistant Professor Community and Family Medicine and Pediatrics Medical College of Wisconsin
www.drjen4kids.com
Birth Weight, Bilirubin and Blood Sugar What Do All the Numbers Mean for Newborn Care? Jenny Thomas, MD, MPH, IBCLC, FAAP, FABM
Breastfeeding is Normal
Birth weight How would you lose 10% of your body weight in three days?
Why is Weight Important? • Some weight loss needs no intervention • Some is preventable • Some is real and scary We need to develop skills to know which one it is.
Distribution of weight changes from birth to day 3 of life according to formula supplementation category.
Chantry C J et al. Pediatrics 2011;127:e171-e179
Š2011 by American Academy of Pediatrics
Distribution of weight changes from birth to day 7 of life according to formula supplementation category on day 3.
Chantry C J et al. Pediatrics 2011;127:e171-e179
Š2011 by American Academy of Pediatrics
Conceptual framework includes potential confounding variables and effect modifiers. Noel-Weiss et al. International Breastfeeding Journal 2011 6:9 doi:10.1186/1746-43586-9
Flaherman et al, Pediatrics, Dec 2014
What We Can Do • Look at rate of weight loss • Watch stool output • Fix problems early • Maybe use 24 hour weight as “birth” weight
Hypoglycemia
What Happens Normally • After birth, the nutrient flow the baby received through the placenta is interrupted allowing maternal metabolism to transition to lactation. • Glucose is the main source of energy for the brain. • However, immediately after birth and before the onset of suckling there is a time in which the newborn undergoes a unique kind of "starvation" where glucose is scarce. This normal and expected. • The energy balance is eventually regained through human milk nutrients which supply the newborn with ketone bodies required for energy.
Normal Glucose Homeostasis • Other metabolic fuels are used as the source of energy for the neonatal brain. • The neonatal brain can use not only glucose, but lactate, pyruvate and, ketone bodies (KBs). • These substrates are then converted into acetyl-coenzyme A, the main input for the citric acid (Krebs) cycle leading to ATP (energy production).
Consequences Outside the Brain • In the lung, acetoacetate works better than glucose as a precursor for the synthesis of lung phospholipids. • The synthesized lipids are incorporated into surfactant, and may therefore have a role in maintaining lung function during the early days of life.
Symptoms are Key • Symptomatic blood sugar can show up as irritability, seizures, lethargy, turning blue, coma, not being able to maintain your temperature, irregular breathing, among other evil things. • Now look at that list and see if we want to chalk any or one of those symptoms up to just a low blood sugar. That baby could be sick. Really sick. Like "take them to the ICU sick."
Symptoms are the Key • Low blood sugar with no symptoms. Not an issue. • Breastmilk meets the nutritional requirements of healthy, term infants and those same healthy term exclusively breastfed infants do not develop symptomatic low blood sugar because they are not eating. • Healthy term infants do not need to have their blood sugar screened.
Symptoms are the Key • Low blood sugar with symptoms: Big problem. • These children have some reason they can’t make up for low blood sugar with other fuels. • Those kids should be screened. Because then, the number means something.
2.22
1.94
1.38
2.49
PEDIATRICS Vol. 127 No. 3 March 1, 2011 pp. 575 -579
Jaundice in the newborn
Bilirubin and Breastfeeding
Definitions • Bilirubin: Bilirubin is the yellow breakdown product of normal heme catabolism. • Jaundice: A yellow coloring of the skin and whites of the eyes. Comes from elevated levels of bilirubin. • Hyperbilirubinemia: description of elevated bilirubin levels in the blood
Adaptation or Disease? • Current view: bilirubin is a toxin and jaundice is a disease • But what if hyperbilirubinemia of the newborn is part of normal newborn adaptation to postnatal life for most infants and represents pathology only for a few?
Adaptation or Disease? • Bilirubin is likely a potentially important antioxidant in the newborn • Explains the presence and pattern of elevated bilirubin better than a model based on disease • May be an expected and valued part of the transition to extrauterine life in a healthy, term newborn without hemolysis
Vitek, L., & Ostrow, J. D. (2009). Bilirubin chemistry and metabolism; harmful and protective aspects. Curr Pharm Des, 15(25), 2869-2883.
Adaptation or Disease? • Bilirubin and kernicterus • Relationship first noticed in relation to hemolytic diseases, principally Rh isoimmunization, in the 1950s. • Noted that as levels of billirubin approached 20 mg/dl (342 µmol/L) the incidence and severity of neurologic injury increased markedly. • Bilirubin becomes a neurotoxin
Adaptation or Disease? • All normal babies will have bilirubin levels above those of an adult because there are physiologic mechanisms that produce and maintain higher levels • Bilirubin serves as an antioxidant in newborns, prior to the maturation of primary antioxidant enzyme systems, serving as an elegant bridge from in utero to extrauterine life.
Measuring Bilirubin What does it mean?
Checking Bilirubin Levels • Act of monitoring bilirubin in an otherwise healthy infant, with or without treatment, can lead to adverse psychological and behavioral consequences • Mothers of jaundiced infants • Less likely to leave their child with anyone • More likely to seek medical attention • More likely to stop breastfeeding
Kemper, K., Forsyth, B., & McCarthy, P. (1989). Jaundice, Terminating Breast-Feeding, and the Vulnerable Child. Pediatrics, 84(5), 773-778.
The AAP is working on a revision.
FIGURE 1 Outcome of newborns who were readmitted with severe hyperbilirubinemia, illustrating the low specificity of TSB in predicting bilirubin neurotoxicity 786.6
649.8
513 µmol/L 478.8 µmol/L 410.4 µmol/L
Wennberg, R. P. et al. Pediatrics 2006;117:474-485 Copyright ©2006 American Academy of Pediatrics
Total Bilirubin • The total serum bilirubin (TSB) level has not been useful as a sensitive and specific predictor of neurological outcomes. • Laboratory and available clinical data are consistent with basic pharmacological principles in demonstrating that free bilirubin rather than TSB is a critical serum factor involved in brain uptake of bilirubin and subsequent neurotoxicity. • Free bilirubin is created when it is not bound to albumin
Treatment For infants with non-hemolytic jaundice, the emphasis remains on treatment rather than understanding and modifying causative factors
Szucs, K. A., & Rosenman, M. B. (2013). Family-Centered, Evidence-Based Phototherapy Delivery. Pediatrics. doi: 10.1542/peds.2012-3479
Things to think about • Current practice is based on expert opinion • There is potential bias in expert opinion • If the concept of free bilirubin makes sense, then our risk factors should change • Breastfeeding is normal, but we do not have any (normal) breastfeeding curves to follow