When I was in labor, I wasn't the only one needing medical attention. My husband blames a hospital cafeteria sandwich on the nausea that sent him racing to the bathroom during my very first push. My mom got a rush of eleventh-hour light-headedness, which led to a nurse rushing to get her a chair and some orange juice.
Encourage your family to speak up if they're feeling sick. Better to have a professional intervene before they throw up or pass out. You can blame them later for trying to steal your thunder.