They look silly, but they are mechanical. They literally pull your nasal passages open from the outside. No drugs, no side effects. Buy the extra strength strips.
When you get your heart rate up, your body produces adrenaline, which naturally shrinks swollen blood vessels (including the ones in your nose). A brisk 10-minute walk can buy you an hour of clear breathing.
These essential pregnancy hormones increase blood flow to all your mucous membranes (yes, all of them). The blood vessels inside your nose swell up, taking up space. At the same time, your nasal passages produce more mucus than usual.