Figure 1.

A, Experimental protocol. At least 5 days after surgery, all fetuses were subjected to an ischemia–reperfusion (I/R) challenge (gray bar). After 1 hour of basal recording, the I/R challenge consisted of 5 compressions of the umbilical cord, each of 10 minutes’ duration (black bars) with a 10-minute interval. Maternal infusion with allopurinol or vehicle started 10 minutes before the fourth umbilical cord compression and finished immediately after the end of it (white bar). Fetal arterial blood samples (arrows) were taken for analysis of blood gas and metabolic status. B, Data are umbilical blood flow (UBF) mean ± standard error of the mean (SEM), before and after each umbilical cord compression in 6 I/R allopurinol pregnancies (black bars) and in 6 I/R vehicle pregnancies (white bars). Significant differences *P < .05 versus baseline (2-way repeated measures analysis of variance with t Newman-Keuls test).