Files and links (1)
Lee_Dissertation_final1.01 MB
Embargoed Access, Embargo ends: 06/29/2027
Dissertation
Impact of advanced maternal age on macrovascular and microvascular function during pregnancy
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Spring 2026
Abstract
Pregnancy at advanced maternal age (AMA), typically defined as ≥35 years, has become increasingly common worldwide and is associated with an elevated risk of adverse pregnancy outcomes, including hypertensive disorders of pregnancy. A healthy pregnancy requires significant maternal cardiovascular adaptations, such as increased cardiac output and decreased peripheral vascular resistance, to ensure adequate blood flow to the fetus and placenta. These substantial hemodynamic adaptations may be partially mediated by enhanced macro- and microvascular endothelial function and reduced arterial stiffness. Insufficient maternal vascular changes during pregnancy are linked to the pathophysiology of pregnancy complications. Thus, alterations in maternal vascular function may contribute to the increased risk of adverse pregnancy outcomes in pregnant women of AMA. However, maternal vascular function across pregnancy in women of AMA is relatively unexplored. The purpose of this dissertation was to comprehensively examine the effect of maternal age on vascular function during pregnancy. We assessed conduit artery endothelial function (flow-mediated dilation, FMD) and aortic stiffness (carotid-femoral pulse wave velocity, cfPWV) across the first, second, and third trimesters (Study 1), and assessed microvascular endothelial function (cutaneous microvascular responses to local heating) during the second trimester (Study 2).Study 1 examined macrovascular function across pregnancy and postpartum in healthy pregnant women of AMA compared with younger pregnant women. A total of 57 younger pregnant women (27 ± 3 years; 21–30 years) and 22 pregnant women of AMA (36 ± 1 years; 35–39 years) were studied. Endothelial function, arterial stiffness, arterial remodeling, and autonomic function were assessed during each trimester and in the postpartum period. Women of AMA demonstrated greater central and peripheral arterial stiffness and increased arterial wall thickness across all trimesters compared with younger pregnant women, with elevated arterial stiffness persisting postpartum. Additionally, women of AMA exhibited lower autonomic function compared with younger pregnant women. However, blood pressure and conduit artery endothelial function did not differ between groups.
Study 2 evaluated microvascular function in pregnant women of AMA compared with younger pregnant women. Cutaneous vasodilatory responses to local heating were assessed during the second trimester in 12 younger pregnant women (28 ± 2 years; 24–30 years) and 14 pregnant women of AMA (39 ± 3 years; 35–47 years). To further determine the effect of age independent of pregnancy, 11 younger never-pregnant women (26 ± 2 years; 23–30 years) and 8 never-pregnant women age-matched to our AMA group (38 ± 3 years; 35–42 years) were also studied. Pregnant women of AMA exhibited attenuated cutaneous vasodilatory responses compared with younger pregnant women. In contrast, there were no group differences in microvascular function between younger and AMA age-matched never-pregnant women.
Collectively, these findings indicate that healthy pregnant women of AMA show altered vascular function during pregnancy, characterized by increased arterial stiffness and reduced cutaneous microvascular function, compared with younger pregnant women. Importantly, the absence of age-related differences in microvascular function among never-pregnant women suggests that these alterations emerge specifically during pregnancy. These data from the two studies provide new insight into maternal vascular function during pregnancy at AMA and may help explain the increased risk of pregnancy complications in women of AMA.
Details
- Title: Subtitle
- Impact of advanced maternal age on macrovascular and microvascular function during pregnancy
- Creators
- Ruda Lee
- Contributors
- Anna E Stanhewicz (Advisor)Gary L Pierce (Committee Member)Mark K Santillan (Committee Member)Nathaniel D.M Jenkins (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Health and Human Physiology
- Date degree season
- Spring 2026
- Publisher
- University of Iowa
- Number of pages
- x, 87 pages
- Copyright
- Copyright 2026 Ruda Lee
- Language
- English
- Date submitted
- 04/28/2026
- Description illustrations
- illustrations (some color)
- Description bibliographic
- Includes bibliographical references (page 74-87).
- Public Abstract (ETD)
More women are delaying pregnancy and having babies at an older age. Women aged 35 years or older, termed ‘advanced maternal age’, face higher risks of health problems for both them and their babies. During a healthy pregnancy, pregnant women’s bodies change to help the baby grow. Blood vessels relax and blood flow increases so more blood can reach the baby. If these changes do not work as well in older pregnant women, it may increase the likelihood of problems during pregnancy. One possible reason for these pregnancy-related problems is that pregnant women’s blood vessels may not adapt properly during pregnancy. This research examined how maternal age affects blood vessel function during pregnancy. We focused on measuring both large and small blood vessel function. Two studies compared blood vessel function measured in pregnant women aged 35 or older with blood vessel function measured in younger pregnant women (18–35 years). The first study measured large blood vessel stiffness and function throughout pregnancy. The second study measured the function of small blood vessels in the middle of pregnancy. The results showed that pregnant women aged 35 or older had stiffer arteries and lower small blood vessel function than younger pregnant women. These findings help us better understand how a mother’s age affects blood vessel responses during pregnancy and may help explain why older pregnant women have a higher risk of health problems during pregnancy.
- Academic Unit
- Health, Sport, and Human Physiology
- Record Identifier
- 9985177173602771
Metrics
1 Record Views