What is the risk of venous thrombosis (VT) in women using different combined oral contraceptives (COCs)?
Studies of women on postmenopausal hormone replacement therapy, women taking non-oral or progestogen-only contraceptives, and those with VT recurrence were excluded. VT was objectively confirmed in all patients in only a few studies.
COC use has been associated with deep VT and pulmonary embolism. The VT risk has been evaluated for many oestrogen doses and progestogen types contained in COCs but no comprehensive comparison involving commonly used COCs is available.