Although the pathophysiology of meconium obstruction of prematurity (MOP) is not clear, it is known that the decrease of the intestinal peristalsis due to decreased intestinal perfusion during antenatal or perinatal period. Recently, the level of citrulline has been used as an index of function and injury of the small intestine State. This study aimed to evaluate citrulline level of cord blood as a marker for early detection and observe changes in intestinal blood flow in MOP patient.

And We aimed to confirm the efficacy of the AT/ET ratio (ratio of the pulmonary artery time-to-peak velocity interval to the right ventricular ejection time) of the prenatal pulmonary artery as a noninvasive predictor of neonatal respiratory distress syndrome.

Inclusion Criteria:

• premature infants born less than 34 weeks from mother with pregnancy induced hypertension, pre-eclampsia or eclampsia

Exclusion Criteria:

• major congenital anomalies
• infants with hypotension while using inotropics

Premature infants born less than 34 weeks who were admitted in neonatal intensive care unit at Seoul National University Children's Hospital