Umbilical cortisol levels as an indicator of the fetal stress response to assisted vaginal delivery Rachel Gitau a,* , Esse Menson b , Victoria Pickles b , Nicholas M. Fisk a , Vivette Glover a , Neil MacLachlan b a Department of Maternal and Fetal Medicine, Division of Paediatrics, Obstetrics and Gynaecology, Institute of Reproductive and Developmental Biology, Fetal and Neonatal Stress Research Centre, Imperial College School of Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, UK b The Department of Obstetrics and Gynaecology, The General Hospital, St Helier, Jersey JE2 3QS, UK Received 7 September 2000; received in revised form 8 January 2001; accepted 15 January 2001 Abstract Objectives: While it is well established that delivery by elective caesarean section is less stressful for the fetus than normal vaginal delivery, little attention has been paid to the effect on the baby of an assisted delivery. Study design: We examined cortisol levels in venous cord blood from seven babies born by forceps, 10 by ventouse extraction, 28 by unassisted normal vaginal delivery, and 12 born by elective caesarean. Paired maternal bloods were taken immediately after delivery. Results: Cord blood cortisol values were signi®cantly different in the different groups one-way ANOVA, P < 0:0001). The forceps group had the highest values and the caesarean group the lowest; both were different from the normal vaginal delivery group P  0:019 and P  0:046, respectively). There was no effect of length of labour, or method of pain relief on cortisol levels. Maternal values were similar in the different groups, con®rming that the differences observed derived from the fetus. Conclusions: There is increasing evidence that the stress experienced by the fetus or neonate can have long-term effects on the function of the hypothalamic±pituitary±adrenal axis in later life. We speculate that the stress caused by some assisted deliveries may contribute to this. # 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Assisted deliveries; Cortisol levels; Fetus; Caesareans 1. Introduction There is increasing evidence that perinatal stress and pain can have long-term effects [1±3]. The most stressful experi- ence undergone by most babies is birth itself [4]. It is well established that the normal birth process is associated with a large increase in the fetus of stress hormones such as cortisol and catecholamines [5±7]. Given that birth is a painful process for the mother, and that the late gestation fetus is considered capable of feeling pain, birth may well be painful for the baby as well [4]. Several studies have shown that caesarean sections are less stressful for the fetus than spontaneous vaginal delivery, in that cord blood cortisol, b- endorphin and catecholamine levels are much lower [8±12]. In contrast, almost no attention has been paid to assisted deliveries despite the clinical impression that assisted deliv- ery is often more stressful for the baby. By measuring cord cortisol levels as a marker of the fetal stress response, we compared two types of assisted instrumental deliveries forceps and ventouse) with two control groups normal unassisted deliveries nvd) and elective lower segment cae- sarean section deliveries). Because we have previously shown a signi®cant correlation between maternal and fetal cortisol levels in utero, suggesting some placental transfer [13], maternal blood samples were, therefore, obtained in parallel. 2. Methods Women were recruited during their antenatal care at The General Hospital, St Helier, Jersey, and written consent was obtained. The study had ethical approval through the local hospital's ethical committee. Women who presented in European Journal of Obstetrics & Gynecology and Reproductive Biology 98 2001) 14±17 * Corresponding author. Tel.: 44-207594-2136. E-mail address: r.gitau@ic.ac.uk R. Gitau). 0301-2115/01/$ ± see front matter # 2001 Elsevier Science Ireland Ltd. All rights reserved. PII:S0301-211501)00298-6