This study was designed to determine the presence and different levels of placental neuropeptide Y (NPY) in women at parturition between normal spontaneous delivery (NSD) and cesarean section (C/S) under spinal anesthesia and to compare it with the level of catecholamines. Umbilical vein plasma levels of neuropeptide Y and catecholamines of the placental cord were measured at delivery in 40 parturient women who were divided into two groups, with 20 patients in each. NSD group underwent vaginal delivery without the presence of intrapartum fetal distress. C/S group received elective cesarean section (C/S) under spinal anesthesia. The results showed that umbilical vein level of NPY in NSD patients was significantly less than C/S patients (160.32 pg/ml vs 346.25 pg/ml, p less than 0.01). But for catecholamines levels, C/S group were significantly less than that of NSD group.