What's going on: No one's sure if pregnant women actually have a sharper sense of smell, but they do perceive odors differently. "If a smell becomes aversive to you, you notice it more," says Beverly Cowart, Ph.D., director of the Monell-Jefferson Taste and Smell Clinic in Philadelphia. This is especially true during those queasy early months, when the slightest whiff of something malodorous may send you sprinting for the nearest bathroom.
What biological function might this bionic nose serve? One theory: During the first trimester, an aversion to noxious odors helps women stay away from foods with a high bacteria content or natural toxins, which could harm the fetus during this crucial period of development. (Not coincidentally, this is also when morning sickness -- with its accompanying food aversions -- reaches its apex.)
As pregnancy progresses, though, moms-to-be may become less attuned to smells than normal, since increased blood flow to the mucous membranes causes them to swell. The result can be what feels like a never-ending head cold and a less-keen nose. If you have frequent nosebleeds or a chronic case of postnasal drip, you can blame hormone-induced nasal engorgement for these problems, too.
What to do about it: Aside from steering clear of fish markets and asking your mate to pick up his java on the way to work rather than brewing a pot at home, not much. For congestion, runny noses, or nosebleeds, use saline nose drops, drink fluids, take 20-minute steamy showers, run a humidifier at night, and keep a box of tissues handy.