Objective: Since its introduction 50 years ago, the contraceptive pill has continuously evolved to decrease the risk of venous thromboembolism (VTE) associated with its use. An increased risk of VTE still remains, however. Other concerns, such as effects on lipid and carbohydrate metabolism, have also been reported. In this study we compared two reference combined oral contraceptives (COCs) containing ethinylestradiol (EE)/levonorgestrel (LNG) and EE/drospirenone (DRSP) with COCs containing estradiol (E2) (estradiol valerate [E2V]/dienogest [DNG] and E2/nomegestrol acetate [NOMAC]). They were evaluated according to their influence on recognised haemostatic and metabolic markers.
Methods: A literature search of the MEDLINE/PubMed database was conducted for head-to-head studies. EE/LNG was chosen as the comparator pill.
Results: The haemostatic impact of E2 pills and EE/LNG has been extensively compared, in contrast to that of EE/DRSP and EE/LNG. Changes in haemostatic and metabolic marker levels between EE/LNG and E2V/DNG were generally not statistically significant. E2/NOMAC showed statistically significantly favourable results on haemostatic markers and had a neutral effect on carbohydrate and lipid metabolism when compared with EE/LNG.
Conclusion: E2/NOMAC exhibits less haemostatic and metabolic impact than EE/LNG and other COCs, suggesting that it may be a promising candidate to reduce residual VTE risk associated with COC use. Confirmation from a well-powered prospective clinical trial is, however, needed.
Keywords: Combined oral contraceptive; Estradiol; Ethinylestradiol; Haemostatic markers; Markers of lipid and carbohydrate metabolism; Progestin; Venous thromboembolism.