Maternal-neonatal serum paraoxonase 1 activity in relation to the mode of delivery.

AIM: To investigate the effect of the mode of labour and delivery on the total antioxidant status (TAS) and the paraoxonase 1 (PON 1) serum activity in mothers and their newborns.

SUBJECTS AND

METHODS

One hundred six women with normal pregnancy were divided into 4 groups: group A (n = 28) with normal labour and vaginal delivery (VG), group B (n = 25) with scheduled caesarean section (CS), group C (n = 26) with "emergency" CS and group D (n = 27) with prolonged labour + VG. Blood was obtained from the mothers at the beginning of the labour process and immediately after delivery (pre- and post-delivery) as well as from the umbilical cord (CB). PON 1 activity and blood chemistry were determined using the Bayer Advia 1650 Clinical Chemistry System, whereas TAS levels were measured spectrophotometrically at 450 min in microtiter plates.

RESULTS

TAS levels were similar pre-delivery and low in CB in all the groups. In contrast, TAS levels were remarkably reduced in group C and in group D post-delivery whereas they were nearly unchanged in group B and just lowered in group A, at the same time of study. PON 1 activity was practically unaltered in group A and group B pre- vs. post-delivery. Interestingly, the enzyme activity was remarkably decreased in group C (222 +/- 16 vs. 153 +/- 14 U/min/mL) and group D (216 +/- 16 vs. 135 +/- 15 U/min/mL, p < 0.001) as compared with those of the other groups at the same time of study. Additionally, PON 1 activity was higher in the newborns of group A and group B than those in group C and group D. TAS and HDL positively correlated with PON 1 activity.

CONCLUSION

The low TAS levels and the decreased PON 1 activity, which were found in groups C and D post-delivery, may be due to the increased production of free radicals, during long-lasting labour + VG and obstructive labour + CS. PON 1 activity was low in CB irrespectively of the mode of delivery, probably due to the low lipid levels in the serum of the umbilical cord. Neonates born with normal delivery or scheduled CS are benefited with a higher antiatherogenic enzyme activity perinatally.