Late Preterm Infants and their complications

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Late Preterm Infants and their complications

• Yousef M Abdulrazzaq

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Background

• PTB has increased by more than 30 in the USA
• 8.5 of all US births in 2002
• Late preterm births account for 71 of all
  preterm births
• Factors associated with PTB increasing
  multiples, C-sections, inductions
• Very preterm birth rate constant
• Recent studies 34-36 weeks increased risk for
  certain morbidities

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Background

• Early discharge (lt48 hr stay after vaginal
  delivery) is a controversial topic
• Studies divided as to associated risk
• AAP recommends early discharge be limited to term
  infants
• Understanding how late preterm infants are
  affected by discharge policies is essential for
  shaping policy and preventing morbidity

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Definitions

• Preterm birth
• lt 37 completed weeks gestation
• Late preterm (or Near- Term)
• 34-36 or 35-36 completed weeks
• Very preterm
• lt32 completed weeks

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Distribution of singleton preterm births U. S.
2002
34-36 Weeks - 74 of all singleton PTB - 7.5
of all births
March of Dimes Perinatal Data Center, 2005
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Born Too Soon The Impact
Percentage of Births
very low, moderately low and low
birthweight United States, 1980,
1990, 2000 and 2003

• United States 1990
• 4,158,212 births
• Preterm Birth 10.6
• United States 2003
• 4,089,950 births
• Preterm Birth 12.3
• 36 weeks 185,000
• 32 - 35 weeks 234,000
• lt 32 weeks 80,000

Martin, JA, Hamilton, BE, Sutton, PD, et al.
National Vital Statistics Reports, Vol. 54, No.
2, 9-8-2005. Births Final Data for
2003, Hyattsville, MD. National Center for
Health Statistics, 2005
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Who are these infants?

• 3/4 of all singleton preterm infants (34-36
  weeks)
• 7.5 of all U.S. births (2003)
• Group rising in number over last decade
• Definition
• Often defined by the Obstetric cut-off for
  Respiratory Distress and maternal antenatal
  steroids 34 weeks
• Clinical management
• Often go to the normal nursery

Late preterm (34-36 wks)
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Higher rates of c-sections and inductions among
singleton live births 1992 and 2002
34-36.6 weeks in 2002 C/S 28 Induction
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March of Dimes Perinatal Data Center, 2005
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Race/ Ethnicity Comparison Singleton Live
Births and Preterm Births,U.S., 2002
14
22
57
50
22
22
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Differences in Singleton Preterm Birth Rates by
Race/Ethnicity, 1992 and 2002
Source National Center for Health
StatisticsPrepared by the March of Dimes
Perinatal Data Center, November 2005.
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Detailed Differences in Singleton Preterm Birth
Rates by Race/Ethnicity, 1992 and 2002
Source National Center for Health
StatisticsPrepared by the March of Dimes
Perinatal Data Center, November 2005.
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What Impact to Infant Health from Rising Late
PTB? Need to separate causes and effects

• Increased morbidities - Higher Neonatal and
  Infant mortality
• U.S. neonatal deaths/1000 live births (2002)
• 34-36 weeks 4.1
• 37-41 weeks 0.9
• U.S. infant deaths/1000 live births (2002)
• 34-36 weeks 7.7
• 37-41 weeks 2.5

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What morbidities associated with Late PTB?

• Increased immediate morbidities
• Respiratory distress
• Jaundice
• Feeding difficulties
• Hypoglycemia
• Temperature instability
• Sepsis
• Increased NICU use (and re-admissions)
• Increased cost
• Long term outcome - ?? - NO DATA!

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Length of Hospital StayFull term vs. Near term
Wang, et al. Pediatrics, 2004
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Frequency of RDS, sepsis and apnea 34, 35, 36
weeks of gestation
Arnon, et al. Paediatr Perinat Epidemiol, 2001
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Clinical Outcomes Full term vs. Near term
Wang, et al. Pediatrics, 2004
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Neonatal Re-admission Diagnoses Among Infants
Discharged Early
Late preterm infants
Term infants

• Massachusetts Pregnancy to Early Life
  Longitudinal Database (PELL)

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Timing of readmission

• Jaundice
• 80 of all readmissions in 1st week for late
  preterm infants versus 56 for term infants
• Day 3 of life most common day for admission
• Infection
• 10 of all readmissions in 1st week for late
  preterm versus 7 for term infants 60 and 53
  in the 2nd week
• On average, late preterm infants presented nearly
  one week earlier than term infants

• Massachusetts Pregnancy to Early Life
  Longitudinal Database (PELL)

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Conclusions from this Study

• Jaundice and infection most common diagnoses upon
  readmission
• Timing similar for jaundice
• Late preterm infants with infection presented
  nearly one week earlier than term infants
• This study illustrates the need for closer
  follow-up of late preterm infants discharged
  early
• Further analyses are needed to understand the
  optimum timing for discharge after birth for
  healthy-appearing late preterm infants

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Near Term BirthsExcess hospital costs
Gilbert, et al. Obstetrics Gynecology, 2003
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Near-term InfantsHyperbilirubinemia (Jaundice)
- 2 reports
4/11 (36) of infants in an HMO with serum
bilirubin of 30 were born at 35-36
weeks Newman, Pediatrics 2003
Sarici, Pediatrics 2004(Turkey)
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Conditions causing morbidity

• Compared to full term infants, these near term
  infants are more likely to have
• positional apnea
• less glycogen and fat stores to prevent
  hypoglycemia
• mild hypotonia
• less alert awake periods
• an uncoordinated suck, swallow, and breathing
  pattern
• a less mature liver

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Conditions causing morbidity

• Areas affecting breastfeeding. LPT have a
  combination of
• mild hypotonia
• less alert awake periods
• an uncoordinated suck, swallow and breathing
  pattern

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Conditions causing morbidity
Poor Infant Sucking
decreased maternal breast stimulation, and
decreased breast emptying
Decreased milk intake
Jaundice
Decreased bilirubin excretion
Decreased milk production
Poor weight gain
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Morbidities of the Near-term Infant

• At one tertiary medical center -
• 34 week babies represented
• 1.6 of deliveries
• 7 of NICU admissions
• 19 of NICU bed-days
• Gladstone, Am J Perinatol 2004

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Late-Preterm Infants and the Most Frequent
Complications of Prematurity During the Birth
Hospitalization

• Outcome During Initial Birth Late-Preterm Term
  Morbidity OR (95 CI) P
• Hospitalization Morbidity
• No. No.
• Feeding difficulties
• Wang et al (35366/7 wk) 29 32.2 7 7.4
  
• Hypoglycemia
• Wang et al (35366/7 wk) 14 15.6 5 5.3
  3.30 (1.112.2) .028
• Jaundice
• Wang et al (35366/7 wk) 49 54.4 36 37.9
  1.95 (1.043.67) .027
• Temperature instability
• Wang et al (35366/7 wk) 9 10.0 0 0.0
  Infinite .0012
• Apnea
• Henderson-Smart (34356/7 wk) 7.0 0.1
  
• Merchant et al (35366/7 wk) 6 12.0 0 0.0
  12.0 (4.524.3) .0267
• Wang et al (35366/7 wk) 4 4.0 0 0.0
  .054
• Respiratory distress
• Escobar et al (34366/7 wk) 345 10.7 975 2.7
  

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Mortality

• Early, late, and post-neonatal mortality rates
  were 6, 3, and 2 times higher, respectively, in
  late-preterm vs term infants.
• Among late-preterm infants, 38 of all infant
  deaths occurred during the early-neonatal period
  (vs 22 for term infants).
• For late-preterm infants, congenital
  malformations were the leading cause of death
  more than half (57) of deaths caused by
  congenital malformations occurred in the first
  week of life, and more than 75 occurred in the
  first month of life. For term infants, these
  proportions were 38 and 61, respectively.

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Conclusions

• "Late-preterm infants experience a higher
  incidence of
• respiratory distress syndrome
• apnea
• transient tachypnea of the newborn
• hypoglycemia
• hypothermia
• hyperbilirubinemia
• feeding difficulties
• longer hospital stays when admitted to the
  neonatal intensive care unit, and
• higher hospital costs
• when compared with infants born at term

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Conclusions

• The rate of preterm birth has increased by nearly
  one third in the United States during the past 25
  years, partly because of
• changes in obstetric practice, such as more
  frequent labor induction and use of cesarean
  delivery before 37 weeks' gestation in women with
  high-risk pregnancy.
• These practices may be partially driven by the
  belief that late-preterm infants are at no
  greater risk for morbidity and mortality than
  term infants.

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Conclusions

• Congenital malformations were the leading cause
  of death for late-preterm infants.
• During infancy, late-preterm infants were
  approximately 4 times more likely than term
  infants to die of
• congenital malformations
• newborn bacterial sepsis and
• complications involving the placenta, cord, or
  membranes.
• "Late-preterm infants have higher mortality rates
  than term infants throughout infancy

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The End