Twin umbilical cord blood gas values

In vaginally delivered births (including a few cases where the mothers were under epidural anesthesia), differences between first and second born twins were compared according to presentation at delivery. Of twins with vertex/vertex presentation in 15 primipara cases and in 14 multipara cases, pO2 levels for the second born were significantly lower (both being p < 0.05) than for the first born. Of twins vertex/non-vertex presentation, the second born in 9 primipara cases showed significantly lower pH, pO2 and HCO3 levels (p < 0.05). Also for multipara twins, the second born had significantly lower pH (p < 0.05) and significantly higher pCO2 (p < 0.05) values. Umbilical cord blood gas value findings indicate unfavourable conditions for second born twins.