Abnormal endothelium-dependent microvascular dilator reactivity in pregnancies complicated by normotensive intrauterine growth restriction

Objective

Normotensive intrauterine growth restriction and preeclampsia share a similar placenta pathophysiology, whereas maternal clinical manifestations differ. Clinical symptoms of preeclampsia are partly attributed to vascular endothelial dysfunction, but it is unclear whether this phenomenon plays a role in intrauterine growth restriction. Therefore, we investigated microvascular endothelial function in women with intrauterine growth restriction.

Study Design

Laser Doppler fluxmetry was used combined with iontophoresis of acetylcholine and sodium nitroprusside, namely, endothelium-dependent and endothelium-independent vasodilators. We studied 12 women with intrauterine growth restriction and 16 controls in the third trimester of pregnancy. All women had prepregnancy body mass indexes < 26.

Results

Acetylcholine-mediated vasodilatation was significantly increased in women with intrauterine growth restriction compared with controls (743% ± 120% vs 390% ± 67%, P = .01); sodium nitroprusside-mediated vasodilatation was not different (360% ± 55% vs 363% ± 65%, P > .99).

Conclusion

Nonobese women with normotensive intrauterine growth restriction show abnormal endothelium-dependent microvascular vasodilatation, suggesting endothelial dysfunction as in preeclampsia. Obviously, for the clinical manifestation of preeclampsia additional factors are required, and a role of metabolic syndrome and obesity has been suggested.

Key words: abnormal endothelial function, acetylcholine, iontophoresis, microcirculation, normotensive intrauterine growth restriction