The Effect of Delivery Mode on Fetal Stress Hormones and Acid-Base Status

Kim, D H; Bang, J B; Kim, C H; Kim, S S; Lee, T H; Jeon, S S; Cho, Y L

Abstract

To evaluate the effect of delivery mode on fetal stress hormones and acid-base status and also to investigate the relationship between fetal acidemia and these hormones. 44 women with term pregnancies were studied. All had singleton, healthy pregnancies. Twenty five women were delivered by spontaneous vaginal route, 10 by vacuum extraction and 9 by elective caesarean section. Umbilical cord blood samples were obtained immediately following the delivery. Blood gas (pH, pCO2, pO2) and hormonal analysis (ACTH, cortisol, dehydroepiandrosterone sulfate) were done in arterial and venous cord blood samples respectively. The cord blood ACTH values were higher in the vacuum extracted group compared to the normal spontaneous vaginal delivery group and caesarean section group (p<0.05). There was also a significant effect of mode of delivery on fetal plasma cortisol levels among three study groups (p<0.05). In contrast, the mean umbilical cord plasma DHEAS levels were similar for all three study groups. High pO2 levels were found in caesarean section group compared to other two groups (p<0.05). Low pH group had higher cortisol and ACTH level compared to high pH group. In conclusion, method of delivery may affect acid-base and stress hormonal status of human fetus.