Prematurity Labor, Delivery

1
Prematurity Labor, Delivery

• Muruvet Elkay, MD
• PL-II
• 12/16/2005

2
Objectives

• Epidemiology
• Risk factors
• Infection
• Role of antenatal steroids
• Complications
• Management

3
Preterm Labor

• Preterm labor (PTL) Presence of contractions
  which cause progressive effacement and dilatation
  of the cervix between 20 and 37 weeks gestation.
  
• Preterm birth (PB) Occurs in 6-8 of
  pregnancies. The incidence has remained stable
  for more than 25 years.

Ref eMedicine Sep 22, 2004 Preterm Labor
Article by Edward R. Newton, MD
4
Terms Related to Prematurity

• Premature infant An infant born before 37 weeks
  of estimated GA.
• Low birth weight (LBW) BWlt2,500 g
• Very low birth weight (VLBW) BWlt1,500 g
• Extremely low birth weight (ELBW) BWlt1,000 g
• Chronologic or birth age Time since birth.
• GA Estimated time since conception
  postconceptional age.
• Corrected age Age corrected for prematurity.
  

Ref David E. Trachtenbarg etal. American Family
Physician 1998 57 (9) 1-11
5
The Epidemiology of Preterm Birth

• Racial differences in the rate of preterm
• LBW VLBW
• African-American women 13.0 3.1
• Asian-Pacific Islanders 7.3 1.0
• Native Americans 6.8 1.2
• Whites 6.5 1.1
• Hispanics 6.4 1.1
• In a twin, triplet or higher order multiple
  gestation 23 of LBW infants

Ref Jay D. Iams, Clin Perinatol 30 (2003)
651-664.
6
US Incidence of Preterm Birth 1992-2002
Ref Edward R. Newton Clin Perinatol 32 (2005)
571-600.
7
Neonatal Morbidity and Mortality by Gestational
Age
Ref Edward R. Newton Clin
Perinatol 32 (2005) 571-600.
8
Hospital Charges by Gestational Age of Delivery
GA (n) Mother Charges Baby Charges Total Charges
25-26 weeks (40) 11,102 192,882 203,994
27-28 weeks (58) 9,765 160,234 169,999
29-30 weeks (76) 10,882 70,684 81,566
31-32 weeks (127) 9,500 36,991 46,490
33-34 weeks (208) 9,016 15,450 24,447
35-36 weeks (240) 6,091 8,484 14,457
gt36 weeks (204) 4,310 2,276 6,586
Ref Edward R. Newton Clin Perinatol 32
(2005) 571-600.
9
Etiology of Preterm Birth

• Physician-initiated birth (indicated PB)
• a. Pre-eclampsia 40
• b. Fetal distress 30
• c. IUGR 10
• d. Abruption placenta or placenta previa 10
• e. Fetal death 5
• Spontaneous PB
• a. Preterm labor (PTL)
• b. Preterm premature rupture of membranes
  (PPROM)

Ref Edward R. Newton
Clin Perinatol 32 (2005) 571-600
10
Risk Factors for PTL and PPROM

• PTL
• Previous PB
• Low body mass
• Poor weight gain
• Heavy work load
• Uterine abnormalities
• Drug abuse, smoking

• PPROM
• INFECTION
• Uterine distension
• Cervical incompetence
• African-American
• Low socioeconomic class
• Drug abuse, smoking

Ref Edward R. Newton Clin
Perinatol 32 (2005) 571-600.
11
The Strong Association Between Infection and
Preterm Birth

• Incidence of subclinical histologic
  chorioamnionitis
• 50 24 to 28 weeks
• 10 gt37 weeks
• The smaller the fetus, the more likely the
  chorioamnion cultures are positive
• 80 lt1000 g
• 30 gt2500 g

Ref Edward R. Newton Clin
Perinatol 32 (2005) 571-600.
12
Relation of Infection and Preterm Birth
Genome
Uteroplacental Insufficiency
Bacteria, Virus, Protozoa
Fetal Stress
Maternal Stress
InfectionLeukocyte Response
?Progesterone Inhibition
?TOLL 4 Receptors
Cytokine Cascade?TNF, ?IL6, ? IL8, etc
Genome
Decidual Activation
Phospholipase A, prostaglandins, lysolethecin,
mettaloproteinases, collagenases, elastases..
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Phospholipase A, prostaglandins, lysolethecin,
mettaloproteinases, collagenases, elastases..
Preterm Labor
Rupture of Membrane
Cervical Incompetence
PRETERM BIRTH
Ref Edward R. Newton Clin Perinatol 32 (2005)
571-600
14
Risk Factors for Infection-Related Preterm Birth

• Historical
• Idiopatic PL, PROM
• History of UTI and STI
• Behavioral
• Unintended pregnancy
• Unmarried
• Multiple partner
• Signs and symptoms
• Vaginal discharge
• Dysuria, dyspareunia

Ref Edward R. Newton Clin Perinatol 32
(2005) 571-600.
15
Prophylactic Antibiotics to Prevent Preterm Birth

• GBS
• Incidence of vaginal GBS- 20-25.
• No association between vaginal GBS and PB.
• Prophylactic antibiotics are not indicated for
  recto-vaginal colonization of GBS.
• Antepartum treatment of GBS in urine.

Ref Edward R. Newton Clin
Perinatol 32 (2005) 571-600.
16
Therapeutic Antibiotics for Infection-Related
Preterm Birth

• GBS Antepartum treatment of all the women
• with the risk factors
• Maternal colonization
• Previous infant who had GBS sepsis
• Antenatal GBS asymptomatic bacteriuria
• ROM gt12 hrs
• Intrapartum fever (probable chorioamnionitis)
• GA lt 37 wks

Ref Edward R. Newton
Clin Perinatol 32 (2005) 571-600.
17
Antibiotics for Inhibiting PL with Intact
Membranes

• Antibiotics are not recommended.

Ref Edward R. Newton Clin
Perinatol 32 (2005) 571-600.
18
Antibiotics for PPROM

• Risk of chorioamnionitis- 20 between 28 and 34
  weeks.
• Antibiotics are recommended in nonlaboring women.

Ref Edward R. Newton Clin
Perinatol 32 (2005) 571-600.
19
Chorioamnionitis

• Inflammation or infection of the placenta,
  chorion, and amnion.
• Histologic, subclinical chorioamnionitis
• gt50 of preterm deliveries
• lt20 of term deliveries
• Clinical chorioamnionitis
• 5 to 10 of preterm deliveries
• 1 to 2 of term deliveries

Ref Rodney K Edwards Obstet
Gynecol Clin N Am 32 (2005) 270-296.
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Clinical Chorioamnionitis

• Most frequent identifiable cause of PL.
• lt30 weeks 50
• PPROM 40
• PL with intact membranes 30
• Maternal fever in the peripartum 10 to 40
• Polymicrobial.

Ref Rodney K Edwards Obstet Gynecol
Clin N Am 32 (2005) 270-296.
21
Clinical Chorioamnionitis

• Diagnostic criteria
• Maternal fever of greater than 100.4 F and at
• least 2 of the following conditions
• Maternal leukocytosis (gt15,000 cells/cubic mm)
• Maternal tachycardia (gt100 bpm)
• Fetal tachycardia (gt160/bpm)
• Uterine tenderness
• Foul odor of the AF

Ref Rodney K Edwards Obstet Gynecol Clin N Am
32 (2005) 270-296.
22
Neonatal Outcomes of Chorioamnionitis

• Intraventricular hemorrhage
• Periventricular leukomalacia
• Cerebral palsy
• Increased rates of bacteremia
• Clinical sepsis
• Increased mortality
• Low Apgar scores
• Hypotension
• The need for resuscitation at the delivery
• Neonatal seizures

Ref Rodney K Edwards Obstet Gynecol Clin
N Am 32 (2005) 270-296.
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Antenatal Steroids

• Indicated in the delivery of a fetus at 24-34
  weeks gestation in the absence of clinical
  infection.
• Delay of delivery- A minimum of 12 hours.
• Duration of benefits-7 days or more?
• Betamethasone or Dexamethasone?
• Reduces the incidence of IVH and NEC.
• An adverse impact of multiple courses on fetal
  growth and development.

Ref eMedicine Sep 22, 2004 Preterm Labor
Article by Edward R. Newton, MD.
24
Benefits of Antenatal Steroids Last 7 Days or
More?

• 197 neonates
• Group I 98 delivered within 7 days
• Group II 99 delivered more than 7 days
• Group I Lower incidence of receiving respiratory
  support more than 24 hrs.
• No significant differences between the groups in
  other measures of neonatal morbidity.

Ref Alan M. Peaceman et al. Am J Obstet Gynecol
2005 193, 1165-9.
25
Betamethasone or Dexamethasone

• 201 preterm singleton infants
• GA between 24 and 34 weeks
• Neurodevelopmental outcome at 2 years corrected
  age
• Results Multiple antenatal courses of
  DEXAMETHASONE associated with an increased risk
  of leukomalacia and 2-year infant
  neurodevelopmental abnormalities.

Ref Spinillo A et al. Am J Obstet Gynecol
2004191 (1) 217-24.
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Complications of Premature Infants

• RDS
• IVH
• NEC
• ROP
• CLD (BPD)
• Infection
• Anemia
• PDA
• Apnea
• Cryptorchidism
• Inguinal hernia
• Umbilical hernia

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SGA and IUGR Are They Synonymous?

• SGA Birth weight below the 10th percentile for
  GA or gt 2 standart deviations below the mean for
  GA.
• IUGR A process that causes a reduction in an
  expected pattern of fetal growth.
• 1. Symmetric IUGR
• 2. Asymmetric IUGR (head-sparing IUGR)
• All IUGR infants may not be SGA (Ponderal index).

Ref Utpala G et al Pediatr Clin N Am 200451
639-654.
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Neonatal Complications of IUGR or SGA

• Metabolic disorders Hypoglycemia, hypocalcemia
• Hypothermia
• Hematologic disorders polycytemia
• Hypoxia birth asphyxia, meconium aspiration,
  persistent fetal circulation
• Congenital malformation

Ref Utpala G et al Pediatr Clin N Am 200451
639-654.
29
Long-term Complications of IUGR or SGA

• Cardiovascular disease
• Hypertension
• Type 2 diabetes

Ref Utpala G et al Pediatr Clin N Am 200451
639-654
30
A Premature Infant may be a SGA or IUGR Infant
Also- Double Jeopardy!

• An adverse outcome resulting from both immaturity
  and deficient intrauterine growth.
• Increased risk for mortality and major neonatal
  morbidities, including RDS, BPD, ROP, and NEC.
• Intensified complications of prematurity by the
  effect of suboptimal fetal growth.

Ref Rivka H. Regev et al Clin Perinatol 2004
34 453-473.
31
Management of Premature Infants

• Delivery room management
• Temperature and humidity control
• Fluids and electrolytes
• Blood glucose
• Calcium
• Nutrition

• Respiratory support
• Surfactant
• PDA
• Transfusion
• Skin care
• Other special considerations

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THANK YOU

• Special Thanks to Dr. Manuel V. and Colin Bird
  MSIII