الفهرس 
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Abstract
egulation of the fetal HPA axis is a highly complicated process and is under the control of positive and negative feedback circuits, placental hormones, and local autocrine/paracrine mediators or growth factors.
The primary aims of this complex system are to ensure appropriate coordination of tissue growth and differentiation, orderly maturation of vital organ systems, and ultimately to act together with the placenta to determine the exact timing of parturition most suitable for successful transition from intrauterine to extrauterine life. A low secretory capacity of the adrenal cortex may cause a diminished stress response during the acute illness in newborn infants and could lead to increased morbidity in these infants.
We performed this study to evaluate the levels of serum basal and ACTH stimulated cortisol, and ACTH in healthy full term Egyptian neonates.
The current study was carried out in Obstetrics and Gynecology Hospital, Ain Shams University and Banha Teaching Hospital during the period of July 2013 to August 2014, written consents were taken from the parents of babies included in the study.
This work included the study of 25 full term healthy neonates, 17 females and 8 males. All studied neonates were appropriate for gestational age (AGA). Their age ranged from 38 to 40 weeks with a mean value 39.28 + 0.79 wks and their birth weight ranged from 2.75-3.75 kg with a mean value of 3.17 + 0.26 kg (AGA). Neonates with any factor that might affect the HPA axis were excluded from the study (e.g., in utero growth retardation, preterm neonates, congenital infection or malformation, perinatal infections, chromosomal abnormalities, infants whose mothers received corticosteroids or other hormonal therapy, poor Apgar score and any evidence and /or history of metabolic disorders).
All studied infants mothers were subjected to full medical history (diseases especially endocrinal & autoimmune and drug intake), antenatal history (drugs, hormonal therapy, pre-eclampsia, placental insufficiency, gestational diabetes mellitus, corticosteroids administration, congenital infection and premature rupture of membranes) and family history (endocrinal disorder and metabolic disorder). None of our studied infants had family history of any previous disorders especially those suggestive of adrenocortical dysfunction nor hyperpigmentation of the skin and/or mucous membranes nor maternal cortisol injection throughout their pregnancy.
All studied infants were subjected to full history and through clinical examination careful assessment for heart rate, respiratory effort, muscle tone, response to catheter in nostril and color for Apgar score at 1st and 5th minutes were done. In addition, Weight, length, Occipito-frontal circumference were measured. Also, laboratory assessed for basal cortisol, ACTH, and ACTH stimulated cortisol levels was done.
Our results revealed the following:
Sixty percent of neonates were born by c. section and forty percent by normal vaginal delivery. Among studied neonates, being the first born baby was the most frequent order of birth while being the 5th was the least common. Our studied neonates had Apgar score at 1 minute that ranged from 5-8 with median 7 and IQR 1.5 and at 5 minutes ranged from 8-10 with median10 and IQR 1.
There was a non significant difference between neonates delivered by C. section and neonates born by normal vaginal delivery. No significant difference between males and females as regards clinical evaluation (maternal age, gestational age, birth weight, length, occipito-frontal circumference, Apgar score at 1 and 5 minutes).
Basal cortisol levels ranged from 2.30 ug/dl to 9.50 ug/dl with a mean value of 6.98 ug/dl + 1.86 ug/dl. All the studied infants showed an adequate response to rapid ACTH stimulation test.
Significant positive correlations were detected between basal serum cortisol and each of Apgar score at 1st and 5th minutes and ACTH stimulated serum cortisol.
There was a non significant difference between males and females, neonates delivered by C. section and neonates born by normal vaginal delivery as regards basal cortisol and ACTH stimulated serum cortisol levels.
Serum cortisol (basal and ACTH stimulated) was not significantly correlated with birth weight, length or with gestational age.
ACTH levels ranged from 13.10 pg/ml to 22.10 pg/ml with a mean value 17.83 +2.35 pg/ml.
A significant positive correlation among was detected between serum ACTH and Apgar score at 5 minutes.
ACTH levels showed non significant differences between males and females, neonates delivered by C. section and neonates born by normal vaginal delivery.
Serum ACTH was not significantly correlated to birth weight (kg), length or with gestational age (wks).