The effect of low-dose combined oral contraceptive pills on brachial artery endothelial function and common carotid artery intima-media thickness

Combined oral contraceptives (COCs) are considered for their thrombogenicity and the risk of premature atherosclerosis and the stroke caused by them. The aim of this study was to evaluate the relationship between chronic use of low-dose COCs (ethinyl estradiol 30 mcg + levonorgestrel 150 mcg) and endothelial dysfunction and intima-media thickness.

In a cross-sectional study, in 2011-2012, 60 healthy premenopausal women (30 cases of COC consumers and 30 controls as nonconsumers), aged between 25 and 45 years, participated in this study. They were current users for at least a 3-year period. Brachial artery flow-mediated dilatation (FMD) and common carotid artery intima-media thickness (CCA-IMT) were measured for the patients.

The mean duration of COC consumption was 54.03 ± 27.27 months in the case group. There was a significant FMD% difference between 2 groups of cases and controls: 11 ± 3.53 versus 15.80 ± 9.22 (P = .01). In addition, a significant mean CCA-IMT thickness difference was detected: .53 ± .07 versus .44 ± .08 (P = .00). However, after multiple regression analysis and adjusting for body mass index (BMI), in COC users, no significant association between COC consumption duration and FMD% and mean CCA-IMT was observed.

Prolonged used of low-dose COCs may cause changes in both endothelial function (measured by FMD%) and endothelial structure (measured by CCA-IMT). There was a nonsignificant inverse relationship between the duration of COC ingestion and FMD% and a nonsignificant positive relationship with CCA-IMT. Our results are in favor of early atherosclerotic changes in prolonged users of COCs.