The Late Preterm Infant

Family and Community Medicine Grand Rounds

April 11, 2012

Nicole J. Urrea, M.D.Heather Pratt-Chavez, M.D.

Objectives1. Discuss recent trends in late

preterm births

2. Explain the risk of infant morbidity in the late preterm infant and common complications in this population

3. Discuss the impact of late preterm birth on childhood outcomes

Late Preterm Infants

•Define late preterm infant (LPI) GA. Why do we need a special name for this group?

•Epidemiology

•Etiology

Late Preterm Infants•Morbidity and mortality in NB

period (first 2-4 weeks of life)

•Apnea

•Respiratory distress

•Poor feeding - dehydration

•Hyperbilirubinemia

•Hypoglycemia – hypothermia

•Sepsis - SBI

Case: Baby Hunter27 y.o. G2P1 at 35 0/7 weeks gestation with

severe pre-eclampsia -

Will my baby be OK?

When can I take him home?

Why does he have to stay in the hospital?

Definition•34 0/7 to 36 6/7 weeks gestation

•2005 workshop, Eunice Kennedy Shriver National Institute of Child Health and Human Development

•2007 report by AAP Committee on Fetus and the Newborn

•What happened to draw this attention?

Definition

Kominiarek M, Engle W. Clin Perinatol,2008

Why the shift?• Increased surveillance - improved ultrasound

technology, (increased form 68.1%-85.4% 1989-2003)

• Infertility treatments - increased multiple gestations (2.4% - 3.2%)

• Increased rates of PROM and preterm labor, PTL increased by 13.8%; PROM by 10.4% (1993-2002)

• Dating problems - iatrogenic• Davidoff MJ, 2006

2005-2006

Births at University of Cincinnati

Ananth CV, Gyamfi C, Jain L.Am J Obstet Gynecol. 2008 Oct;199(4):329-31.

Epidemiology Where are we now?

•In US, total births in 2010 = 4,000,279

•Late Preterm Births in 2010 = 339,625 (8.49%)

Hamilton BE, Martin JA, Ventura SJ. Births: Preliminary data for 2010. National vital statistics reports web release; vol 60 no 2. Hyattsville, MD: National Center for Health Statistics. 2011.

Epidemiology

•In New Mexico total births in 2010 = 27,028

•Late Preterm total = 2,352 (8.7% of total births)

Timing of Indicated Late-Preterm and Early-Term Birth.Obstetrics & Gynecology. 118(2, Part 1):323-333, August 2011.

© 2011 The American College of Obstetricians and Gynecologists. Published by The American College of Obstetricians and Gynecologists.

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Table 1.Timing of Indicated Late-Preterm and Early-Term Birth.Spong, Catherine; Mercer, Brian; DAlton, Mary; Kilpatrick, Sarah; MD, PhD; Blackwell, Sean; Saade, George

Obstetrics & Gynecology. 118(2, Part 1):323-333, August 2011.DOI: 10.1097/AOG.0b013e3182255999

Table 1. Guidance Regarding Timing of Delivery When Conditions Complicate Pregnancy at or After 34 Weeks of Gestation

© 2011 The American College of Obstetricians and Gynecologists. Published by The American College of Obstetricians and Gynecologists.

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Table 1.Timing of Indicated Late-Preterm and Early-Term Birth.Spong, Catherine; Mercer, Brian; DAlton, Mary; Kilpatrick, Sarah; MD, PhD; Blackwell, Sean; Saade, George

Obstetrics & Gynecology. 118(2, Part 1):323-333, August 2011.DOI: 10.1097/AOG.0b013e3182255999

Table 1. Guidance Regarding Timing of Delivery When Conditions Complicate Pregnancy at or After 34 Weeks of Gestation (continued)

Early Morbidity

and Mortality

What milestones are missed by

infants born late preterm?

Neurologic Immaturity

Neurologic Immaturity

Decreased awake state

Low tonePoor coordination of

suck/swallow/breathe

Apnea (17.7 RR)SIDS (1.37 RR)

Teune MJ, et al. Am J Obstet Gynecol. 2011 Oct;205(4):374.e1-9Hunt CE Semin Perinatol 2006

Lung Immaturity

Lung Immaturity

Use of nasal oxygen - 6% of late preterms

(24.4 RR)

RDS - 5.3% (17.3 RR)

Gastro-Intestinal Immaturity

Slowed transit

Less UGT - bilirubin

metabolism

Increased enterohepatic

circulation

Gastro-Intestinal Immaturity

Feeding Difficulties - 34% of late preterm infants

Hyperbilirubinemia - 18.8% of late preterm

infants

Prolonged and delayed presentation

Metabolic Immaturity

Small size

SGA

Less brown fat

Less white

adipose

Metabolic Immaturity

Hypoglycemia - 7.1% of LPIs

Hypothermia - 1.5% of LPIs

Immune System ImmaturityIncomplete activity of both humoral and cellular immunity

Low storage of neutrophils

IgG increases with GA

Mechanical barriers and mucosal surfaces decreased stratum corneum

Immune System Immaturity

More sepsis work-ups - 19.7% of late preterms

Sepsis (RR 5.6) Meningitis (RR 21)

PNA (RR 3.5) NEC (RR 7.5)

Mortality

National Vital Statistics Reports, June 2011

Newborn Period

•Missed events of development in last 6 weeks of gestation = morbidity risks in newborn period

Newborn period

•Tell families their baby will stay until close to their due date

•Every baby is different

•Some presentation is delayed, need to follow closely

Case: Baby Hunter•Delivered by cesarian

section, 2300 grams

•No respiratory distress, vitals stable, glucose 75, admitted to ICN3, nippled well on day 1 and 2 with advancing feeding volumes, working on breast-feeding

Case

•Day 3 and 4, Hunter is more easily fatigued with nippling, some lower temps recorded, naso-gastric tube placed, nippling now once per shift, mom expressing breast milk

Case

•Day 5, Hunter’s needs phototherapy for increasing bilirubin, still working on feeds, poor weight gain

•Day 6-8, Hunter’s mom has to return to Gallup to care for 2 y.o. at home, still trying to express and store breast milk

Case

•Day 12, taking full feeds, waking every 2-3 hours to feed, gaining weight, passed car seat trial, ready for discharge

Nutrition

•Breastmilk

•Human-milk fortifier?

•Formula?

•Many challenges in the breastfeeding late preterm infant

Breastfeeding CascadeLess stamina

Less coordinated S/S/BLess effective suckling

Less alert, awake periods

Insufficient breast stimulation

Incomplete emptying

Insufficient milk transfer

Insufficient milk supply HypoglycemiaJaundice

Poor weight gain

ReadmissionSupplementation

Separation from mother Wight, Pediatric Annals 2003;

32:5

Breastfeeding Management Strategies

• Kangeroo skin-to-skin contact

• Strong evidence of increased breastfeeding at 1 month after discharge (RR 4.76, 95% CI 1.19 to 19.1) and for more than 6 wks (RR 1.95, 95% CI 1.03 to 3.7)

• Minimize pain during painful procedures

• Peer support

• Simultaneous pumping

• Multidisciplinary staff training

• Baby Friendly accreditationRenfrew et al., Health Technol Assess, 2009

Growth• Catch up growth

• Abnormal growth patterns may be associated with adult morbidity

• Limited investigations on the growth development of LPIs

• Santos et al. BMC Pediatrics, 2009

• Risk of being underweight was at least two folds higher for LPIs

Readmission•LPIs are readmitted 2 to 3 times more

often than term infants

•Common reasons:

• Jaundice, infection, feeding issues, failure to thrive

•Risk factors:

•Primigravida mother, breastfeeding, maternal complications, public insurance and Asian/Pacific Island heritage

Readmission after NICU DischargeGroup (LOS) n Percentage

RehospitalizedDiagnoses

≥ 37 wk (< 96 h) 2593 2.2 Jaundice (46%)r/o sepsis (20%)Feeding diff (13%)

≥37 wk (≥ 96 h) 1133 2.8 Jaundice (25%)Feeding diff (16%)CHD (9%)

33-36 wk (< 96 h) 545 5.7 Jaundice (71%)Feeding diff (16%)r/o sepsis (6%)

33-36 wk (≥ 96 h) 1196 2.2 Dehydration (28%)Jaundice (20%)r/o sepsis (20%)

< 32 wk (all LOS) 587 3.4 Bronchiolitis (21%)GER (16%)Hernia repair (10%)

Escobar et al., Pediatrics 1999

Neurodevelopmental Outcomes

Neurodevelopmental Outcomes

• Few studies

• Neurologic abnormalities, learning difficulties, poor scholastic achievement, and behavioral problems have been reported

• CP is three times more likely

• DD and MR have been found to be 1.3-2 times more likely

• No evidence of increased risk of autism has been reported

Arpino et al, Childs Nerv Syst, 2010

Engle, Clin Perinatol, 2011Data from Moster et al., N

Engl J Med, 2008

Learning Disability•Compared to full

term:

•LPIs have 24% increased odds for reading scores below average in the first grade of education

•1.4-2.1 risk for special education Arpino et al, Childs Nerv Syst,

2010

Morse et al., Pediatrics, 2009

Early School and Developmental

Outcomes

•61 healthy infants born between 33-36 weeks gestation

•At 12 and 18 months corrected GA, LPI showed a mean developmental index similar to term infants

Romeo et al., Euro Ped Neur Soc, 2010

Case: Baby Hunter•Hunter is seen by his pediatrician for his

9 month well child check

•He continues to breastfeed and mom has introduced solids without difficulty

•He babbles, says “mama”, and likes to play “peek-a-boo”

•On exam his physician notes that he is unable to sit without support

•He is referred to Early Intervention

Linnet KM et al., Arch Dis Child 2006Engle

Cost

Birth Hospitalization

Rehospitalization

Total first year costs (after birth hospitalization)

Length of Stay

Cost

Term 2.2 days $2,061 7.9% $4,069

Late preterm

8.8 days $26, 054

15.2% $12,247

McLaurin et al, Pediatrics, 2009

Future ResearchNational Institute of Child Health and Human

Development: Optimizing Care and Outcome for Late-Preterm Infants

•Education

•Epidemiology and Etiology

•Gestational-age-specific morbidities and mortalities

•Evidence-based intervention guidelines

•Assessing the total cost of LPI birth

•Outcomes of LPIs and relationship to indication for delivery

Conclusions•Although the risk of poor outcome is

less than that of an early preterm infant, LPIs are a vulnerable population.

•Early discharge should not occur in these infants and diligent follow up is important, both in the post neonatal period and for continued long-term care.

•More research is needed

Questions?