... All three of these retrospective studies showed significant and usage durationdependent effects of previous COC use: (i) the duration of previous COC treatment was positively related to gray matter volume in the hippocampus and the basal ganglia, while the time since discontinuation was negatively related to gray matter volume in the hippocampus but not in the basal ganglia ; (ii) ever users of COCs performed significantly better than never users in the domains of visuospatial ability and speed and flexibility, with duration-dependent increases in performance, especially in ever users with ≥ 15 years of use (Egan and Gleason, 2012); (iii) women with short-term use (≤5 years) of COCs had 26 % lower odds of having cognitive impairment compared with those who had never used COCs, whereas the association was not statistically significant (although it was 13 % lower) for those who used for more than 5 years (Song et al., 2020). Unfortunately, there is no information about the progestins used by all (Egan and Gleason, 2012;Song et al., 2020) or the majority of participants in these retrospective studies, as in many other studies that evaluated the effects of COCs on the brain structure,function and cognitive function of women (e.g., Beck et al., 2008;Chen et al., 2021;De Bondt et al., 2013, 2015Hamstra et al., 2014;Holloway et al., 2011;Kuhlmann and Wolf, 2005;McFadden, 2000;Miedl et al., 2018;Mihalik et al., 2009;Nielsen et al., 2011;Petersen et al., 2015b;Pletzer et al., 2010;Rosenberg and Park, 2002;Rumberg et al., 2010;Wen et al., 2021). Some studies provided information about the type of progestins but did not take this factor into consideration in data analyses (Gogos, 2013;Gravelsins et al., 2021;Hamstra et al., 2015;Høgsted et al., 2021;Kerschbaum et al., 2017;Kimmig et al., 2022;Lisofsky et al., 2016;Merz, 2017;Mordecai et al., 2008;Plamberger et al., 2021;Pletzer, 2019;Pletzer et al., 2014a;Sharma et al., 2020), and other studies combined data from participants using different types of HCs (COCs, minipills, IUDs, implants, vaginal rings, etc.) (e.g., Bernal et al., 2020;Nobile et al., 2021;Petersen et al., 2015a). ...