| Antenatal glucocorticoids are given to pregnant women at risk for preterm delivery for improving fetal lung maturity extensively. The longest effective time of glucocorticoids is one week. The protection would disappear if interval between the delivery and therapy is over 7 days .There is about 50% pregnant woman who still hasn't deliveried after being given a course of glucocorticoids for 7-14days.This urged obstetricians to give glucocorticoids to the prenant woman at risk for preterm delivery repeatedly. The findingds of animal models has indicated that repeat glucocorticoids has negative effect on the fetus lung and nervous system development .The doses of antenatal glucocorticoids is directly related with the degree of brain damage. But there still hasn't final conclusion in clinic report at present. The purpose of this study was to investigate the possible effect of exposure to multiple antenatal steroid courses on fetus brain development.Subjective and Methods118 preterm infants deliveried between 27 and 34 weeks' gestation from Aug.2005to Jan.2007 were enrolled this study in our NICU. These infants were divided into three groups by the antenatal courses of corticosteroids: control group,single-course group and multi-course group. Supportive threatments were given in all groups. Birth weight,head circumference,length,serum cortisol in stress and non-stress,mortality,morbidity of RDS and time of mechanical ventilation(MV), intraventricular hemorrhage(IVH) were all monitored in three groups. Clinic follow-up include: Neonatal Behavioral Neurological Assessment (NBNA) was evaluated on expected date of delivery. Mental and Pxycho-motor developmental Index was evaluated at 3 month,6month,12month,18 month by using Intellectual Development Table made by Children's Development Center of China(CDCC). Results1. General information:The sample obtained consisted of 39 non-exposed newborns, 40single-course exposed and 39multi-course exposed newborns .There were no significantly differences in generalize case, perinatal period, Sex, gestational age, birth way, preterm newborn complication and maternal pregnancy complication among three groups.2. Clinical assessment1)Growth and development index of birth: There were significant lower of mean birth weight in preterm newborns exposed to multi- course than that of single-course exposed and non-exposed group. But there were no differences between single-course exposed and non-exposed group. Birth length were no statistics differences among all the three groups. The exposure to multi-course corticosteroids resulted in a significant reduction of head circumference than the other groups. Yet there were no differences between single-course exposed and non-exposed group.2)Morbidity of NRDS and IVH: Antenatal corticosteroids reduced the morbidity of respiratory distress syndrome. But there were no differences between single-course exposed and multi-course exposed group. Both single-course and multi-course antenatal corticosteroids treatment could reduce the rate and time of using MV ,shorten the mean time of length of stay.The morbidity of intraventricular hemorrhage (IVH) of multi-course exposed group was 46%, the non- exposed group was 20% and single-course exposed group was 33% .The morbidity of the multi-course exposed group and the non-exposed group are higher than the single-course exposed group.(p<0.05) 3)Serum cortisol in stress and non-stress: density of serum cortisol in stressand non-stress of the multi-course exposed group was similar with the other groups.4) Intra-hospital mortality: Antenatal corticosteroids reduced themorbidity of intra-hospital. But the morbidity did not show statistical significant differences after single and repeat courses of corticosteroids.3 Follow-up of development1)NBNA: The score of NBNA was much higher in single-course exposed group than that of multi-course exposed group and non- exposed group.2)CDCC assessment: At 3 month of corrected age, the score of MDI and PDI was94.11±14.97,97.77±14.84 in multi-course exposed group, which was low to that of single-course exposed group (MDI 110.54±10.05,PDI 112.41±11.55 ) and non-exposed group(MDI 106.79±9.95,PDI 112.31±6.42).Significant difference was also found at 6,12 month age.3) Neurodevelopmental abnormalities analysis of the infants at 1-1.5 years corrected age: The proportion of multi-course exposed group was 3/10compaired with single-course exposed group1/12, non-exposed 3/10.The difference was obvious. These neurodevelopmental abnormalities appeared as hyperactivity,attention deficit,language fallen behind and cerebral palsy.Conclusion:1) Antenatal dexamethasone were effective in the reduction of morbidity of RDS and mortality among premature newborns. But there were no difference between single-course group and multi-course group.2) Exposure to repeat courses of antenatal dexamethasone has affected the short-term and long-term neurodevelopment.3) Therapeutic effectiveness of antenatal single course dexamethasone is certain. We should avoid to use antenatal dexamethasone repeatedly. |
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