New Daysy Study!

Has your cycle been affected by the pandemic?

Many women have reported cycle and period changes since March 2020. In our current study, we systematically examined cycle data. We compared and analyzed 13,194 anonymized cycles from more than 1000 Daysy users in 2019 and 2020. The result confirms what many women already suspected, the cycle shortened by 1 day on average in the first half of the pandemic, while the duration of menstruation increased significantly, especially during the first lockdown.

The result of the study summarized:

  • In the first half of 2019, the average cycle lasted 29.8 days; in the first half of 2020, it lasted only 28.7.
  • The follicular phase (before ovulation) shortened from an average of 17.12 days to 16.2.

In order to analyze the extent to which women perceived the pandemic as psychosocially stressful, participants were asked in the second part of the study to answer a questionnaire (Summer 2021) about themselves and their personal situation, during and before the pandemic.

  • 44.4% of participants reported that they had noticed a change in their menstrual cycle, temperature curve, or menstruation in the past 12 months. Among women who had experienced COVID-19 themselves or in their family member(s), the rate was higher (53.9%).
  • Sixty-nine percent reported a change in quality of life during the previous 12 calendar months. Forty-one percent of these women perceived this change as an improvement.
  • Among the 102 women who themselves or their family member had experienced COVID-19 disease (38% of all respondents overall), many perceived the changes as negative instead. 46% of respondents reported that their quality of life had worsened during the past 12 months.

Future studies

The cycle data from 2019 and 2020 provides an objective overview of changes in the menstrual cycles of users of a fertility tracker. It supports the hypothesis that stress affects the cycle and fertility overall. The authors of the study emphasize that future studies should focus on cycle changes during the most stressful phases of the pandemic to provide more precise information about the relationship between stress and menstruation.


Daysy - Your personal fertility tracker (incl. app DaysyDay)
299.00 EUR

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Daysy is an intelligent fertility tracker that lets you get to know your very own menstrual cycle.