The Relationship Between Delivery Mode and Cord Blood Betaendorphins Values in the Newborns of Nulliparous Women

Background & Aims of the Study: Beta-Endorphin (β-EP), as the main stress hormone, is secreted during delivery and labor and modifies the pain threshold and sensation. This study aimed to determine the umbilical cord blood level of β-EP and its related factors in two groups of nulliparous women with Natural Vaginal Delivery (NVD) and Elective Cesarean Section (ECS). Materials and Methods: This case-control study was conducted on 80 pregnant women (40 cases & 40 control) at 38-42 weeks of gestation. Besides, the study subjects presented no history of chronic diseases, pregnancy complications, abortion, stillbirth, or infertility. The explored cases were women with NVD and the control were women with ECS. After delivery, a 3-mL blood sample was collected from the placental umbilical cord. After separating the blood serum, the β-EP level was examined using a standardized β-EP kit (Glory Co., USA). Data analysis was performed in SPSS using the Chi-squared test, t-test, and Fisher’s Exact test (P≤0.05). Results: The study groups were matched on individual, social, and obstetric characteristics, such as age, educational level, occupational status, gestational age, body mass index, and the frequency of prenatal care. The obtained results indicated that the umbilical cord blood levels of β-EP were significantly higher in the NVD group, compared to the ECS group (P=0.03). Conclusion: The present research results suggested that NVD provides greater effects on the release of β-EP, in comparison with ECS.