Effect of maternal undernutrition in early gestation on ovine fetal blood pressure and cardiovascular reflexes

Human epidemiological and animal experimental studies suggest that maternal undernutrition during pregnancy may alter cardiovascular development of th e offspring. The extent to which these effects involve changes in fetal car diovascular function and whether they are necessarily linked to reduced fet al growth is unknown. In sheep, we investigated the effect of a 15% reducti on in maternal global nutrition for the first 70 days of gestation (term = 147 days) on fetal blood pressure development, baroreflex control of fetal heart rate (FHR), and cardiovascular responses to acute hypoxemia in late g estation. Basal mean arterial pressure (P < 0.05), systolic blood pressure (P, 0.05), diastolic blood pressure (P < 0.05), and rate-pressure product ( P < 0.001) were significantly lower in fetuses of nutritionally restricted ewes (R) compared with controls (C). FHR was not altered. The operating poi nt for the fetal baroreflex was significantly lower in R fetuses compared w ith C (P < 0.01), but there was no difference between the groups in the car diovascular response to hypoxemia. We conclude that mild maternal undernutr ition alters fetal cardiovascular development, producing low blood pressure and resetting of baroreflex control mechanisms. This effect occurs without any changes in fetal growth or blood gas status.