> Cerebral venous sinus thrombosis is rare, with an estimated 3-4 cases per million annual incidence in adults. While it may occur in all age groups, it is most common in the third decade. 75% are female. [0]

6 cases in 7 million over 3 months with mostly women being affected is exactly what we'd expect to see.

[0] https://en.wikipedia.org/wiki/Cerebral_venous_sinus_thrombos....