00407nas a2200133   4500000000100000008004100001100001900042700001600061700002100077245014300098300001000241490000800251022001400259       2015                            d1 aY. Vinogradova1 aC. Coupland1 aJ. Hippisley-Cox00aUse of combined oral contraceptives and risk of venous thromboembolism: nested case-control studies using the QResearch and CPRD databases  ah21350 v350  a0959-8138