This stopped being a simple scheduling conflict the moment your coworker told your boss you “don’t understand because you don’t have kids.” That false narrative was then used to pressure you into giving up approved leave, which makes it important to document exactly what was said and how it was repeated. Keeping a clear record protects you if this behavior escalates.
Going forward, treat approved leave as final—no explanations, no debates. If the pattern continues, loop in HR early to put context on record, especially with future maternity leave approaching. This isn’t about starting conflict; it’s about setting boundaries and preventing your personal life from being used against you at work.