complications of the combined oral contraceptive pill

Last edited 03/2021 and last reviewed 03/2021

  • increased mortality due to pulmonary embolism, cerebral thrombosis, myocardial infarction; smoking habit and age are the principal determinants:
    • no excess mortality if non-smoker & < 35 years
    • excess mortality of 10 per 100,000 woman years if smoker and < 35 years
    • excess mortality of 15 per 100,000 if non-smoker and > 35 years
    • excess mortality of 50 per 100,000 if smoker and > 35 years

  • thromboembolism - oestrogen increases platelet count and adhesiveness, and reduces anti-thrombin; the low oestrogen content of modern combined pills has made deep vein thrombosis and pulmonary embolism rare, but progestogen only pills are advised if there is pre-existing heart disease

  • metabolic - reduced glucose tolerance; increased levels of serum corticosteroid binding protein and thyroxine; progesterone increases LDL's and reduces HDL's, so increasing risk of stroke and myocardial infarction

  • hypertension - increased release of hepatic renin precursors

  • increased risk of gallbladder disease in susceptible patients

  • cancer - effect on breast / cervical cancer. There is an association between use of the combined oral contraceptive and cervical cancer. The risk of breast cancer is described in the linked item

  • menstruation - some women develop amenorrhoea, especially if cycles were previously irregular; no delay / acceleration of onset of menopause