Possible Risk of Thrombotic Events following Oxford-AstraZeneca COVID-19 Vaccination in Women Receiving Estrogen

Biomed Res Int. 2021 Oct 25:2021:7702863. doi: 10.1155/2021/7702863. eCollection 2021.


People who receive the ChAdOx1 nCoV-19 vaccine, particularly perimenopausal women who are on birth control or postmenopausal women who take estrogen supplements, may experience thrombosis and thrombocytopenia. Estrogen and the ChAdOx1 nCoV-19 vaccine both have the potential to cause thrombus in different ways. Some postmenopausal women who are also taking estrogens may develop thrombosis and thrombocytopenia after receiving the ChAdOx1 nCoV-19 vaccine. Therefore, women are encouraged to stop taking drugs containing estrogen before receiving this vaccine. Furthermore, consuming fish oil can help reduce the risk of developing blood clots among women who are in the luteal phase and, thus, have high estrogen levels. In addition, ChAdOx1 nCoV-19's side effects in young women could be mitigated by administering it during the follicular phase.

Publication types

  • Review

MeSH terms

  • COVID-19 Vaccines / adverse effects*
  • COVID-19*
  • ChAdOx1 nCoV-19
  • Estrogens / administration & dosage*
  • Female
  • Humans
  • Menopause
  • SARS-CoV-2
  • Thrombocytopenia / etiology
  • Thrombosis / etiology*
  • Vaccination / adverse effects*


  • COVID-19 Vaccines
  • Estrogens
  • ChAdOx1 nCoV-19