the effect of preoperative treatment with an estrogen containing oral contraceptive on the incidence of postoperative thrombosis ( detected with 125i-fibrinogen leg scanning ) was examined in 221 patients aged 18-49 years who had elective or emergency general intra-abdominal or gynecologic surgery , 99 of whom were taking an oral contraceptive before their operation .
C0038902
gynecologic surgery
C0543467
operation