Inclusion Criteria:  spontaneous, singleton pregnancies above the 24 weeks of gestations positive fetal cardiac activity  Exclusion Criteria:  multiple gestations, chronic hypertension hypothyroidism known malignancy,- diabetes mellitus, presence of fetal or maternal infection, clinical signs of chorioamnionitis (maternal fever, vaginal discharge, fetal tachycardia), hepatic or renal failure Placenta previa or pregnancies accompanied congenital fetal abnormalities or aneuploidies