Introduction: Intrauterine devices (IUDs), an increasingly popular method of contraception, may exert systemic adverse effects on cardiovascular health. Markers of oxidative stress are increased in IUD users six months following insertion, and oxidative stress is implicated in vascular endothelial dysfunction in women. The objective of this analysis was to test whether IUD use is associated with altered microvascular endothelial function, and if this is mediated in part by oxidative stress. Methods: Naturally-cycling (NAT; n=5; 44 ± 1 yrs) and IUD using (n=5; 46 ± 3 yrs) premenopausal women participated. Red blood cell flux (laser Doppler flowmetry) was measured in response to a standardized local heating protocol (42°C) alone (control, CON) or during concurrent intradermal microdialysis perfusion of the non-specific antioxidant ascorbate (AA) to assess endothelium-dependent dilation. This was followed by perfusion of N(G)-nitro-l-arginine methyl ester (L-NAME; 15mM) to quantify nitric oxide (NO)-mediated dilation. Results: Local heating-induced vasodilation was lower in the IUD women at CON compared with NAT women (80.9 ± 9.2 vs 96.6 ± 6.1%, P = 0.02), but not NO-mediated dilation (58.7 ± 10.0 vs 70.6 ± 13.4%, P = 0.15). AA improved vasodilation in the IUD women (14.7 ± 4.1 %Δ, P < 0.01) but not in the NAT women (-8.9 ± 15.6 %Δ, P = 0.27) such that they were not different (P=0.20). Similarly, AA improved NO-mediated vasodilation in the IUD women (15.8 ± 4.1 %Δ, P < 0.01) but not in the NAT women (-11.8 ± 27.7 %Δ, P = 0.41) such that they were not different (P=0.12). Conclusions: Our preliminary findings suggest that microvascular endothelium-dependent dilation is attenuated in IUD-using midlife women. This effect may be explained in part by oxidative stress, indicated by a favorable response to local antioxidant perfusion in IUD users. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Nuckols et al. (Fri,) studied this question.