Assessment of endothelial function in normal twin pregnancy

Objective To assess the maternal endothelial function in normal twin pregna ncy. Design Cross-sectional study. Subjects Endothelial function was investigated in 74 women with normal twin pregnancy at 11-30 weeks of gestation and the results were compared to pre vious reported findings in 98 women with normal singleton pregnancy and 19 nonpregnant controls. Methods Endothelial function was assessed by measuring the changes of the b rachial artery diameter in response to reactive hyperemia (flow-mediated di latation) using external high resolution ultrasound. Results Flow-mediated dilatation of the brachial artery in both twin and si ngleton pregnancies was significantly higher than in non-pregnant women (P = 0.002 and P = 0.02, respectively). However, there was no significant diff erence in flow-mediated dilatation between women with twin and singleton pr egnancy (9.61 +/- 4.36 vs. 8.84 +/- 3.18, P = 0.38). Resting vessel size, b aseline flour and reactive hyperemia did not change significantly with gest ation in twin pregnancy and were similar to values in singleton pregnancies and controls. Conclusion Our findings indicate that although in pregnancy endothelial fun ction is enhanced, this change may not be affected by the number of fetopla cental units present.