[Umbilical acid-base status of term infants: correlation with delivery mode]

To determine possible relations between Apgar score, umbilical artery haemogasanalysis and delivery mode.

948 babies were considered; preterm infants and charts with incomplete data were excluded. 762 newborns and their respective umbilical artery blood gas parameters at delivery were evaluated. The collected Data were related to mode of delivery: vaginal with and without analgesia, elective caesarean section (CS), CS after labour, emergency CS for non reassuring trace.

Mean pH (+/- DS) was 7.26 (+/- 0.08). The comparison vaginal delivery vs. CS was statistically significant (p < 0.0001). Analyzing the CS only, the babies born by emergency CS for non reassuring trace had pH statistically lower (ANOVA p < 0.004) and, in the latter group, there was a statistically difference between Italian newborns and those from other ethnicities (p < 0.02). No difference were found on Apgar score, excluding babies by vaginal delivery with analgesia that showed lower scores both at 1 (p < 0.02) and 5 (p < 0.002) minutes versus newborns without analgesia.

Normal labour causes frequently a mild degree of acidosis, but it is not always related to neonatal asphyxia. The differences found between different delivery modes are, probably, the expression of causes related to the obstetric choice. That is also remarked by the statistically difference found in emergency CS for non reassuring trace in Italian population and in other ethnicities, showing a probably different cultural level, mainly about the "obstetric emergency" poorly understood by the pregnant. In vaginal deliveries the analgesia does not modify the neonatal metabolism, but can be a reason of delayed adaptation of extrauterine life.