Four months after my son’s arrival, my hair began to fall out. It started quietly with the strands falling softly from my head while I slept, covering pillowcases and duvets in an almost invisible layer of curved hair. Elsewhere, they crawled across the back of the couch where my head had touched the soft velvet cover while feeding, silently growing in number as the days went on. Before long, it was everywhere I looked. In...