Nearly every pregnant woman experiences it: an increased awareness of how things smell. From certain foods to skin products to body odor, a wide variety of things trigger nausea and even feelings of anger, happiness, or depression. There doesn't seem to be any sort of adaptive mechanism to blame for a pregnant woman's sensitivity to certain smells. Nor, do "pregnant women have olfactory processes different from non-pregnant women," according to a 2005 study in BJOG: an International Journal of Obstetrics and Gynecology.
Yet regardless of studies, certain odors can send pregnant women running straight to the bathroom. This perceived heightened sense of smell seems to affect pregnant women most during the first trimester and can also accompany morning sickness—or at least start the gut churning.
What is it about being pregnant that causes women to gag at certain odors and not others? According to Dr. Bill Sears, Associate Clinical Professor of Pediatrics at the University of California, Irvine, School of Medicine and author of over 30 books on childcare, the same reason is to blame that causes most other pregnancy complaints, from mood swings to food cravings: hormones!
That's right, hormones. And since hormones are to blame, the physical cause of heightened olfactory sensitivity can't really be explained—even though pregnant women through the ages have complained of significantly adverse reactions to certain smells. So, with everything in your body off kilter, it's no wonder that smells that used to be delightful are now frightful!
Odors Not to Order
Just what sorts of smells send pregnant women into a gagging fit? "Just about anything that doesn't smell like pickles or ice cream," says Dr. Sears. Olfactory sensitivity in pregnancy is quite individual. Sad to say, you won't know what sets your gag reflexes in motion until the smell hits your nostrils. However, many pregnant women seem to mention certain smells to be particularly heinous, says Dr. Sears. These odors include beans, spaghetti sauce, fish, and eggs.
According to a 2004 study published in Chemical Senses, over 40 percent of pregnant women tested in the first trimester reported increased sensitivity to the smell of cooking odors, cigarette smoke, spoiled food, and perfume. While there may not be scientific evidence that pregnant women have a heightened sense of smell, the experiences of many expecting moms beg to differ.