Relationship between maternal arterial wave reflection, microvascular function and fetal growth in normal pregnancy

In 50 normotensive pregnancies, we examined the relationship between fetal growth, arterial wave reflection, and microvascular function at 22, 34 weeks gestation, and six weeks postpartum.

Arterial wave reflection was determined by measuring augmentation index (AIx). Changes in skin microcirculation to acetylcholine (ACh) and sodium nitroprusside (SNP) were assessed using laser Doppler imaging.

At 22 weeks, birth weight centile correlated with AIx adjusted for maternal age, MAP, heart rate and timing of reflected wave (r = -0.363, p = 0.012), and with ACh responses (r = 0.317, p = 0.022). ACh responses correlated with adjusted AIx (r = -0.420, p = 0.003). At 34 weeks, birth weight centile correlated with the adjusted AIx (r = -0.301, p = 0.048). ACh responses were borderline correlated with adjusted AIx (r = -0.323, p = 0.074). At six weeks postpartum, no significant correlations were found between birth weight centile, AIx, and ACh responses. SNP responses did not correlate with AIx or birth weight centile at any time point.

During normal pregnancy, changes in vascular function might reflect important adaptations that are required to facilitate normal fetal growth. This was highlighted in the present study by the findings of a positive correlation between birth weight and endothelial function and a negative correlation between birth weight and arterial wave reflection.