Authors' conclusions

There are no comparative studies assessing risk of thromboembolism in COVID‐19 patients who use hormonal contraception, which was the primary objective of this review. Very little evidence exists examining the risk of increased COVID‐19 disease severity for combined hormonal contraception users compared to non‐users of hormonal contraception, and the evidence that does exist is of very low certainty.

The odds of hospitalization for COVID‐19 positive users of combined hormonal contraceptives may be slightly decreased compared with those of hormonal contraceptive non‐users, but the evidence is very uncertain as this is based on one study restricted to patients with BMI under 35 kg/m2. There may be little to no effect of combined hormonal contraception use on odds of intubation or mortality among COVID‐19 positive patients, and little to no effect of using any type of hormonal contraception on odds of hospitalization and intubation for COVID‐19 patients. At a minimum, we noted no large effect for risk of increased COVID‐19 disease severity among hormonal contraception users.

We specifically noted gaps in pertinent data collection regarding hormonal contraception use such as formulation, hormone doses, and duration or timing of contraceptive use.

Differing estrogens may have different thrombogenic potential given differing potency, so it would be important to know if a formulation contained, for example, ethinyl estradiol versus estradiol valerate. Additionally, we downgraded several studies for risk of bias because information on the timing of contraceptive use relative to COVID‐19 infection and method adherence were not ascertained. No studies reported indication for hormonal contraceptive use, which is important as individuals who use hormonal management for medical conditions like heavy menstrual bleeding might have different risk profiles compared to individuals using hormones for contraception. Future studies should focus on including pertinent confounders like age, obesity, history of prior venous thromboembolism, risk factors for venous thromboembolism, and recent pregnancy.