My guesses (in order of likelihood): 1) More sleep, and easier to respect their circadian rhythm 2) Reduced un-conscious stress levels related to: the comfort

My guesses (in order of likelihood): 1) More sleep, and easier to respect their circadian rhythm 2) Reduced un-conscious stress levels related to: the comfort of being at home in a safe place...the comfort of knowing they won't go into labor early while far from home and around non-family members...the comfort of knowing they're eliminating unforeseen risks that come with venturing out into the world 3) Significant reduction of non-natural movements/processes such as: getting in/out of car, sitting in stiff desk chair all day, work-schedule dependent restroom use, commuting related stress 4.) Reduced air pollution