Capillary remodelling in normal pregnancy: Can it mediate the progressive but reversible rise in blood pressure? Novel insights into cardiovascular adaptation in pregnancy.

Abstract Objective To conduct a longitudinal study of skin capillary density changes throughout normal pregnancy and correlate them to changes in blood pressure. Design Prospective, longitudinal cohort study. Setting London teaching hospital. Study design Two hundred and twenty-five Caucasian, Primigravid women with singleton pregnancy, normotensive throughout pregnancy, and with normal pregnancy outcomes. We used intra-vital video microscopy to measure basal (i.e. functional) and maximal (i.e. structural) skin capillary density (CD) according to a well-validated protocol. The subjects were studied at baseline (11–16weeks gestation) and at four consecutive visits (20–24weeks, 27–32weeks, 34–38weeks, and 5–15weeks postpartum). Blood pressure measurements were taken during the same visits. Results We found that normal pregnancy was associated with progressive capillary rarefaction, with the overall trend in the fall in both functional and structural CD being statistically significant ( p Conclusions Progressive capillary rarefaction is a normal accompaniment of human pregnancy that may mediate the progressive rise in systolic and diastolic pressures. Both the CD and blood pressure changes are reversible, returning to baseline in the puerperium.