Short answer: No. In Jainism, menstruation is not considered a sin, and performing puja (pooja) or devotional practice during periods is not prohibited by core Jain teachings.

Key points to understand:

• Impurity concept: Jainism does not teach ritual impurity as a permanent moral flaw. Many Jain texts emphasize inner purity, right conduct, and proper intention (bhav) rather than a blanket “impure/pure” label tied to bodily states.
• Pooja and devotion: Pooja is a personal act of devotion and self-discipline. You may engage in prayer, meditation, or devotional reading during your period if you feel drawn to it and if it aligns with your vows and comfort.
• Tradition vs. principle: Some Jain communities or temples may have local customs about participation in certain communal rites or temple activities during menstruation. These are cultural practices, not universal Jain doctrinal rules. If you are unsure about a specific temple or community, it’s reasonable to follow the local guidance or ask calmly for the favored practice there.
• Digambar vs. Shwetambar: There is no fundamental difference in stance about the permissibility of pooja during periods between these two main sects. Any differences you encounter are typically regional or temple-specific rather than core doctrinal differences.

Bottom line: It is not considered a sin to perform pooja during periods in Jainism. The emphasis remains on sincere devotion, self-discipline, and the intention behind one’s spiritual practice. If you have a particular temple or lineage in mind, you can check their local guidelines, but there is no universal prohibition in Jain teachings.