1. ‫الرحمن‬ ‫ا‬ ‫بسم‬
‫الرحيم‬

2. Repeated Doses of AntenatalRepeated Doses of Antenatal
CorticosteroidsCorticosteroids
for Women at Risk of Preterm Birthfor Women at Risk of Preterm Birth
Ahmed Alaa el dinAhmed Alaa el din
Assistant Lecturer of OB/GYNAssistant Lecturer of OB/GYN
Cairo UniversityCairo University

3. Introduction
 Preterm birth is a leading cause of perinatal death and disability
and is an important public health problem globally.
 Administration of corticosteroids to mothers before preterm
delivery significantly reduces perinatal morbidity and mortality.
 Complications of preterm birth include:
-Respiratory distress.
-Intraventricular hemorrhage.
-Periventricular leukomalacia.
-Necrotizing enterocolitis.
-Need for mechanical ventilation & admission to NICU.
-Perinatal death.

4. Mechanism of
Action of Antenatal
Corticosteroids

5. A. Respiratory Action
 Antenatal corticosteroid therapy leads to architectural and
biochemical changes that improve both lung mechanics and gas
exchange. These changes are primarily the result of accelerated
morphologic development of type 1 and type 2 pneumocytes.
Type 1 pneumocytes are responsible for gas exchange in the
alveoli, while type 2 pneumocytes are responsible for production
and secretion of surfactant.
 Antenatal corticosteroids also alter production of surfactant
binding proteins and enhance fetal lung antioxidant enzymes.
 However, for these changes to occur the lungs need to have
reached a stage of development that is biologically responsive to
corticosteroids.

6. B. Circulatory Action
 Antenatal corticosteroid therapy improves circulatory stability in
preterm neonates, resulting in less intraventricular hemorrhage
and necrotizing enterocolitis.

7. Rationale for
Repeating antenatal
corticosteroids

8. Rationale for Repeating
antenatal corticosteroids
 The biologic rationale for repeating antenatal corticosteroid
therapy is based upon the observation that biochemical
stimulation of surfactant production appears to be reversible in
cell culture models i.e. surfactant protein mRNA levels decline to
control levels after cortisol is removed.
 However, other beneficial effects, such as cytostructural
maturation, persist after steroid exposure is withdrawn.

9. Effective Antenatal
Corticosteroid
Regimens

10. Corticosteroid Regimens
 Corticosteroid regimens shown to be effective include:
betamethasone 12 mg intramuscularly, 2 doses 24 hours apart;
or dexamethasone 6 mg intramuscularly 4 doses 12 hourly.
 Benefits were found when treatment was started between
26 and 35 weeks of gestation, and for babies born 1–7 days after
commencing treatment.
 No benefits were demonstrated for treatment commenced, or
infants born, before 26 weeks of gestation, nor for those born
more than seven days after treatment.

11. Corticosteroid Regimens
 Some studies showed that betamethasone is associated with
lower incidence of RDS compared to dexamethasone.
 Dexamethasone is associated with lower incidence of
intraventricular hemorrhage, but with higher incidence of
puerperal sepsis (especially if taken orally).

12. Advantages
& Disadvantages of
Repeated Antenatal
Corticosteroids

13. Advantages
 Repeated doses are associated with better neonatal lung
function than single course of corticosteroids, particularly among
infants delivered before 32 weeks of gestation.
 Also, less need for mechanical ventilation, continuous positive
airway pressure, and surfactant use. There was also a reduction
in the frequency of pneumothorax.
 However, there is NO SIGNIFICANT BENEFIT in reduction of
severe respiratory distress syndrome, grade III or IV
intraventricular hemorrhage, chronic lung disease or
periventricular leukomalacia.

14. Disadvantages
 Repeated doses are associated with lower birth weight than the
single course, and appear to cause IUGR.
 However, it was found that repeating a SINGLE RESCUE DOSE
or COURSE, does not affect fetal growth.
 Some studies reported increased incidence of cerebral palsy.
 Regarding late term effects, some studies showed affection of
neurological development in early childhood.

15. Disadvantages
 In animals: studies have shown decreased brain size, altered
nerve growth, a delayed rate of myelination, altered retinal
development, a decrease in the number of neurons and a dose-
dependent degeneration of neurons in the hippocampus.
Also it may be associated with increased incidence of
hypertension.

16. Recommendations

17. Recommendations
 We recommend repeating a SINGLE RESCUE DOSE or
COURSE of antenatal corticosteroids only in cases who have
passed
7 days since initial administration & are still at risk of preterm
labor.

18. Thank
you