Background Vaginal delivery, especially operative assisted vaginal delivery, seems to be a major stressor for the neonate. The objective of this study was to evaluate the stress response after metal cup versus Kiwi Omnicup® ventouse delivery. Methods The study was a secondary observational analysis of data from a former prospective randomised placebo controlled multicentre study on the analgesic effect of acetaminophen in neonates after operative vaginal delivery and took place at three Swiss tertiary hospitals. Healthy pregnant women ≥35 weeks of gestation with an estimated fetal birth weight above 2000 g were recruited after admission to the labour ward. Pain reaction was analysed by pain expression score EDIN scale (Échelle Douleur Inconfort Nouveau-Né, neonatal pain and discomfort scale) directly after delivery. For measurement of the biochemical stress response, salivary cortisol as well as the Bernese Pain Scale of Newborns (BPSN) were evaluated before and after an acute pain stimulus (the standard heel prick for metabolic testing (Guthrie test)) at 48–72 h. Results Infants born by vaginal operative delivery displayed a lower pain response after plastic cup than metal cup ventouse delivery (p < 0.001), but the pain response was generally lower than expected and they recovered fully within 72 h. Conclusions Neonatal pain response is slightly reduced after use of Kiwi OmniCup® versus metal cup ventouse. Trial registration Trial was registered under under NCT00488540 on 19th June 2007.
