OBNeonatal Practice and Infant Mortality

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OB/Neonatal Practice and Infant Mortality

• Mark Klebanoff, MD, MPH
• DESPR, NICHD, NIH, DHHS

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Table 1. Infant deaths and infant, neonatal, and
postneonatal mortality rates United States,
1933, 1940, 1950, 1960, 1970, and 1975-2001
final, and 2002 (preliminary and latest
processed)  Rates per 1,000 live births
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Perinatal Mortality, US, 2000-2002
NCHS, 2004
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Calculating Survival Rates

• Infant mortality experience of U.S. is more
  complicated than just a number. Clinical
  decisions need to be considered
• What is the denominator?
• All infants (includes stillbirths)
• All live born infants
• Infants admitted to NICU
• Treatment withheld or withdrawn?
• What is the numerator?
• Neonatal survival (28 days)
• Survival to NICU discharge
• Survival to 1, 2 or 3 yrs

Adapted from Allen, 2004
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Time Trends in Birth Outcomes - U.S.
From NCHS, 2004
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Time Trends in Gestation, Single Births - U.S.
From NCHS, 2004
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Birthweight-specific Mortality, US, 2001
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Why Has Preterm Birth Increased?

• Multiple births
• fraction of births that are twin and higher order
  has increased during the 1990s
• increase greatest among non-Hispanic white women,
  who presumably have greater access to ART
• Why?
• Assisted reproductive technology?
• Increased births to older women?
• Increased obesity in reproductive-age women?

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Why Has Preterm Birth Increased?

• However, preterm birth has risen among singleton
  births as well
• 9.7 in 1990, 10.4 in 2002
• All of the increase in singletons has been in
  moderately preterm birth (32-36 weeks) single
  births lt32 weeks declined very slightly

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Induction of Labor, US, 1991 and 1998
Zhang, 2002
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OB Care at the Border of Viability

• Obstetrical Intervention Indicated Preterm
  Birth
• Cesarean without labor, or induction of labor
• Usually secondary to a medical or obstetrical
  complication (most commonly preeclampsia, fetal
  distress, IUGR)
• Maternal health compromised, and/or prenatal
  care-giver decides that the fetus has a better
  prognosis in the nursery than in the uterus
• Not able to capture indicated births reliably
  on the birth certificate (only says method of
  delivery, not whether there was spontaneous labor
  or PROM)

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Willingness to Perform Cesarean by Gestational
Age, MFMU Network 1992-3
Bottoms, et al 1997
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Lowest Gestational Age at Which Obstetricians
Would Perform Cesarean Delivery, 2001
percent
Weeks gestation
McElrath TF. A J Perinatol 20029
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Delivery Room Care of the 500-749 g Infant,
Cleveland OH
Hack and Fanaroff, 1999
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Outcome of Liveborn Infants with Birthweight lt750
gColorado, 1991-1996

• Live births 1021 infants
• No intervention 162 infants, all died
• Attempted resuscitation 859 infants
• No response 103 infants, all died
• Response 756 infants
• NICU Care Begun 756 infants
• Basic care only 36 infants, all died
• Advanced Care 720 infants
• Neonatal death 332 infants
• Survivors 388 infants (38)

Hernandez, 2000
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Neonatal Outcome by Obstetrician Willingness to
Intervene for Infants at 24 Weeks
Willing
Not Willing
S. Bottoms, MFMU, AJOG 1997
Slide courtesy of Brian Mercer, MD
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Willingness to Perform Cesarean

• Most variation in willingness occurred at 23-24
  weeks and 500-800 g
• In multivariable analysis, willingness to do
  section more strongly associated with survival
  than actual performance of a section
• No stillbirths when OB willing to perform a
  section for fetal distress
• Willingness to intervene increased likelihood of
  both intact survival and serious morbidity

Bottoms, et al 1997
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IUGR Abn. FHR at Border of Viability
Confirm IUGR FHR Abn
Ultrasound, FHR monitoring
Diagnostic Work-up
Maternal
Fetal
Medical Intervention/Therapy?
No
Yes
Continue pregnancy with intensive monitoring
Delivery might improve outcome
Delivery wont improve outcome
Steroids, Antibx3 center
Supportive care
Wenstrom, 2004
Atraumatic delivery
Await labor or IUFD
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Over a Range of Gestational Ages from 21-26 Weeks
and a Range of Obstetricians and Neonatologists,
Interventionist Approach to Fetal/Neonatal Care

• Unreasonable Investigational Optional Mandator
  y
• Between 20 wks 27 wks, a difference of little
  as 1-2 wk in gestational age estimate can change
  the decision whether to initiate intervention

Adapted from Tyson, 2004
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LMP Accuracy
Kramer et al, 1988
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Accuracy of Prenatal U/S Obtained at lt 26 weeks
BPD ? 7-10 days FL ? 7-11 days AC ? 2.8
weeks BPD 40 mm is consistent with 16
weeks (90th ) 19 weeks (10th ) 17
weeks (50th )
Mongelli, 1996 Tunov, 1996
Wenstrom, 2004
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Calculating Survival Rates

• What is the denominator?
• All infants (includes stillbirths)
• All live born infants
• Infants admitted to NICU
• Treatment withheld or withdrawn?
• What is the numerator?
• Neonatal survival (28 days)
• Survival to NICU discharge
• Survival to 1, 2 or 3 yrs

Adapted from Allen, 2004
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Hypothesis

• Recent national increase in infant mortality is
  an artifact due to obstetricians and
  neonatologists adopting more aggressive
  management of threatened fetuses and/or newborns
  on the margin of viability
• Pregnancies that would have ended in stillbirth
  are being delivered, resuscitated and taken to
  the NICU

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Suggestion

• Perinatal audit of stillbirths and neonatal
  deaths in a region over the past several years
  looking for changes in
• Obstetric management (use of tests of fetal
  well-being)
• Obstetric intervention, such as induction or
  cesarean without labor, as a result of the
  discovery of a compromised fetus
• Aggressive delivery room management (intubation,
  use of CPR, drugs)
• Initiation of neonatal intensive care