Relación entre el intervalo de nacimiento entre gemelos y el pH de cordón umbilical: ¿existe asociación entre la acidosis del primer gemelo y el segundo?

SUMMARY Objectives: Determinate if the twin-to-twin vaginal delivery time interval, is related with a decline of the arterio-venous cord blood pH of the second twin regarding to the first twin, and to evaluate if the acidotic pH of first twin can predict the acidosis status of the second one. Method: A retrospective descriptive cohort study was performed at the Hospital of Getafe, Spain, in the period 2008-2013, with 77 pairs of twins that were registered and met the inclusion criteria. The twin-to-twin delivery time interval and the cord blood status results were registered. A statistical analysis was performed to study the relation of the twin-to-twin delivery time interval with the pH value differences between first and second twins, and with the base excess. Results: A positive linear correlation between the twin-to-twin delivery time interval and the difference of venous pH of the second twin respect to the first one was found (R=0.560; p=0.0001), and also with the difference on arterial pH (R=0.502; p=0.0001). A pH value <7.20 of the first twin was associated with blood cord acidosis of the second twin (<7.20, p=0.000; <7.15, p=0.0001; <7.10, p=0.0001; <7.05, p=0,001; <7.00, p=0.0001). Conclusions: The second twin pH was equal to or less than the first twin pH in all cases. There is a linear relation between twin-to-twin delivery time interval and the decrease of the pH value of the second twin regarding to the first one. The acidosis of first twin could predict the acidosis status of the second twin.