الفهرس 
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Abstract
In the human embryo, development of lung starts as early as 3 weeks of embryonic life and continues into postnatal life up to early adulthood. lung development has been divided into five stages: embryonic, pseudo-glandular, canalicular, saccular, and finally the alveolar stage.
The respiratory system is the anatomical system of an organism
that introduces respiratory gases to the interior and performs gas
exchange.
For effective gas exchange to occur, alveolar spaces must be
cleared of excess fluid, and pulmonary blood flow increased to match
ventilation with perfusion. After birth, the pulmonary fluid is actively absorbed, and with
introduction of air into the lungs, an air/liquid interface, facilitated by
surfactant, forms the alveolar lining. Surfactant has three predominant roles; to increase pulmonary
compliance, to prevent atelectasis at the end of expiration and facilitate
recruitment of collapsed airways. In addition surfactant has a role in
protecting the lungs from injury and infection caused by foreign bodies
and pathogens.
Preterm birth continues to be a major health problem throughout
the world. Infants born preterm are at increased risk of death and
neonatal morbidities such as respiratory distress syndrome, intra ventricular hemorrhage, and broncho-pulmonary dysplasia, which, in
turn, increase the risk of abnormal neurodevelopmental outcomes in later
life.
Respiratory distress syndrome occurs primarily due to surfactant
deficiency and is the most common cause of respiratory distress in the
preterm infant, but can also be seen in infants born at term. The classic clinical presentation of RDS in infant born between
29 and 33 weeks of gestation comprises grunting respirations, chest wall
retraction, nasal flaring, cyanosis and increased oxygen requirement,
together with diagnostic radiographic finding and the onset of symptoms
occurs shortly after birth. Administration of glucocorticoids (GCs) during pregnancy is an
established practice for reducing morbidity and mortality of fetuses at
risk of preterm delivery. A single course of antenatal steroids (AS) remains the standard of
care for women at risk for preterm delivery between 24 and 34 weeks of
gestation, and significantly decreases mortality and RDS. The optimal
response to a course of AS occurs if it is given at least 24 hours before
but within 7 days of delivery. Corticosteroid regimens shown to be effective include: betamethasone
12 mg intramuscularly, 2 doses 24 hours apart; or dexamethasone
6 mg intramuscularly 4 doses 12 hours apart.
The study was done on (40) pregnant women admitted to
Al-Menshawy hospital with gestational ages between 32 to 35 weeks of
pregnancy and their preterm infants.
All pregnant women received a single course of ACS (2 doses of
12-mg dexamethasone intramuscularly with 24-hour interval).
For the analysis, patients were categorized in 4 groups: ACS to
delivery interval from 0-7 days, from 8-14 days, from 15-21 days, and
from 22-28 days. The interval was calculated from the day that the first
dose of the ACS course was given.
N.B: Each neonate who was born from a multiple pregnancy was
analyzed separately.
Our study showed that:
Neonates with Apgar score >7 were 35(79.5%).
Most of the neonates 38 (86.4%) did not need neonatal ventilator and
6 (13.6%) neonates needed for neonatal ventilator.
Neonates who needed post-natal corticosteroids were 14(31.8%).
Neonates who had chronic lung disease were3 (6.8%).
The need of ventilation was significantly low when delivery was
done after 7 days minimum of administration of corticosteroids (P value
0.046).
Corticosteroid administration is effective in reducing neonatal
lung disease when delivery done in 7 days minimum after administration
of corticosteroids.
The percentage of neonates diagnosed with R.D.S in relation to
corticosteroid administration, delivery interval showed that number
of neonates diagnosed with R.D.S was significantly low (P value 0.002)
when delivery is done 7 days minimum after introduction of corticosteroids.
Apgar score more than 7 was only significant (P value 0.029)
in the group when delivery was done 7 days minimum between
introduction of corticosteroids and delivery interval.
Respiratory morbidity was significantly high with corticosteroid
administration, delivery interval between 0-7 days (P value 0.001).
Respiratory morbidity was significantly higher when gestational
age at delivery was low ranged between 32-33ws while it was
significantly lower when gestational age at delivery was high more than
36ws.