Commentary on: Increased stiffness of omental arteries from late pregnant women at advanced maternal age

Abstract

Worldwide, pregnancy at age 35 or older, termed 'advanced maternal age (AMA)', is increasing exponentially. As the incidence of pregnancy at AMA has increased, a growing body of evidence has suggested that AMA is also associated with increased risk for adverse maternal and fetal outcomes outside of genetic anomalies. Importantly, despite the mounting evidence and the increased global risk of adverse perinatal outcomes observed, few studies have examined the potential mechanisms underlying this elevated risk in pregnant people ≥35 years of age. Wooldridge and colleagues begin to address this gap in the literature. In their recent report, they examine vessel stiffness in omental resistance vessels obtained from pregnant individuals ≥35 years of age compared with pregnant individuals <35 years of age. Omental arteries were isolated and assessed via pressure myography (mechanical properties) and histological analysis for collagen and elastin content. Overall, the findings from this investigation report that maternal resistance arteries collected from women of AMA were less compliant and had less elastin than arteries obtained from women <35 years of age, suggesting that maternal resistance vessel stiffening in AMA may contribute to increased risk of adverse pregnancy outcomes. The authors should be commended for completing these studies in human resistance vessels, which now open new avenues for investigation and provoke a cascade of questions related to maternal cardiovascular adaptations to pregnancy in women ≥35 years of age.

Keywords: aging; cardiovascular physiology; pregnancy.

Figure 1. Possible Mechanisms Underlying Increased Resistance Artery Stiffness in Advanced Maternal Age

Advanced maternal age (AMA, pregnancy at ≥35 years of age) is associated with increased omental artery stiffness – increased circumferential strain and decreased elastin content – at term (∼38–39 gestational weeks) compared with young (<35 years of age) pregnant women [7]. This increased stiffness may be due to an age-associated increase in pre-pregnancy resistance artery stiffness, a maladaptation to the cardiovascular demands of the pregnancy, or a combination of the two, driving changes in underlying vascular mechanisms. Plausible underlying mechanisms include reduced endothelium-dependent dilation, increased baroreflex sensitivity, and/or increased vasoconstrictor sensitivity, compared with pregnancy in healthy young women.