RESUMO
OBJECTIVES: Assisted deliveries (ADs) are used in current practice by obstetrical teams during labor when the fetus is likely to face difficulties. In this study, we hypothesized that pain related to instrumental delivery could impair autonomic nervous system (ANS) activity. MATERIALS AND METHODS: We investigated infants born by spontaneous delivery (SD group, n=35) and those whose deliveries were assisted by vacuum, forceps, or both (AD group, n=35) between the second and fourth hours of life. Pain was evaluated using the Echelle de Douleur et d'Inconfort du Nouveau-Né/Neonatal Pain and Discomfort Scale (EDIN) behavioral pain scale. ANS activity was analyzed using the newborn infant parasympathetic evaluation (NIPE) index, a heart rate variability based index which is related to the autonomic activity mediated by the parasympathetic nervous system. RESULTS: Neonates in the AD group presented higher EDIN scores than neonates born by spontaneous vaginal deliveries (SD group) (P<0.0001). In contrast, the NIPE index was significantly reduced in the AD group compared with the SD group (P=0.005). A significant inverse correlation was found between the NIPE index and the EDIN score (r=-0.287, P=0.016). DISCUSSION: ADs (vacuum, forceps, or both) are associated with persistent pain after birth, unlike normal vaginal deliveries. Moreover ADs are associated with reduced NIPE. Taken together, our results suggest that pain related to instrumental delivery impairs the ANS activity.