A faint line may just mean you're newly pregnant since pregnancy tests detect the hormone hCG (human chorionic gonadotropin), which your body starts producing when you conceive. Or, it can mean you're very well hydrated since hCG is more detectable in concentrated urine. Later in pregnancy, a faint line can indicate falling levels of hCG and a possible loss, since hCG rates should double quickly through the first 10 weeks.