Heightened sense of smell during pregnancy

About two-thirds of pregnant women say they're more sensitive to scents, a condition called hyperosmia. Changing hormone levels could be the cause. 

Young woman smelling beautiful hydrangea bouquet
Photo credit: / Bogdan Kurylo

Pregnancy brings all sorts of changes to your body: Breasts and belly swelling, glowing skin, and lots of emotions. You might also notice that you have a heightened sense of smell, especially early in your pregnancy. If the odor of eggs cooking or coffee brewing suddenly overwhelms your nose and turns your stomach, you're not alone.

Reports of pregnant women claiming near super-human sniffing abilities have circulated for more than a century. Studies show that about two-thirds of pregnant women are more sensitive to smells, and not necessarily in a good way. Most of the time the enhanced odors aren't pleasant. Experts say those foul smells might be a trigger for morning sickness.

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What's behind the enhanced sense of smell during pregnancy? Research on the subject is limited, but experts do have a few theories.

What is hyperosmia?

Hyperosmia is a medical term used to describe a heightened sense of smell. It means that your nose has become more sensitive at picking up scents.

True hyperosmia is very rare. It may be related to conditions that affect the smell-detecting parts of your brain, like epilepsy, Addison's disease, or migraines.

Experts say that being more sensitive to odors in pregnancy could serve a protective function. A more attuned nose can warn you of something potentially toxic to your baby before you eat it.

When will a heightened sense of smell during pregnancy begin?

Most of what we know about a heightened sense of smell comes from pregnant women's own accounts. And most women who do report more intense aromas say that it happens in the early stages of their pregnancy.

Later in pregnancy, your sense of smell might actually decrease. That's because tissues around your body and in your nose swell with increased blood flow. As your nose swells, you become more stuffed up. Similar to when you have a cold, a stuffed nose makes it harder to detect odors.

Why is my sense of smell so strong during pregnancy?

That's a good question, and one that experts can't answer for sure. One theory is that, like many other changes that happen to your body during pregnancy, shifting hormone levels are behind the stronger sense of smell.

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Human chorionic gonadotropin (hCG) is one possible culprit. This is the hormone your body makes after the fertilized egg implants in the wall of your uterus, and the one a pregnancy test picks up to let you know you're expecting. Rising levels of hCG early in pregnancy match the changes in smell that many pregnant women report.

It's also possible that rather than being more sensitive to odors during pregnancy, you're simply more aware of them. An increased vigilance during these nine months might make you focus more on smells that might be harmful to your growing baby, so you can avoid them.

How can I minimize my sensitivity to smells?

There isn't much you can do to make your nose less sensitive to smells, but you can try to avoid the scents you find most unappealing. Pregnant women in studies rated perfumes, pets, meat, fish, and eggs as some of the most unappealing smells, and fruits as more pleasant.

If the smell of cooking bothers you, eat food cold or at room temperature. You might also wear a mask to block the most annoying odors.

Surrounding yourself with pleasant smells, like mint, lemon, peppermint or cinnamon, might also help. Peppermint oil has been found to be safe in pregnancy, and regularly applying a small amount inside the nostrils may help to block out other, offensive odors. Chewing gum or sucking on candy can help drown out the scents of things you find unpleasant. If bad odors set off a wave of nausea and vomiting, you can ask your doctor if it's ok to take an anti-nausea medication.

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When can I expect my hyperosmia to end?

Your super-keen sense of smell should diminish by the end of the first trimester, around the time morning sickness usually fades, and as your hormones stabilize. Most women notice it completely dissipates by the end of pregnancy, meaning you should be able to say goodbye to those overpowering aromas by the time you deliver. Of course, if hyperosmia persists, check in with your doctor. An underlying medical condition, and not pregnancy, might be to blame.

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BabyCenter's editorial team is committed to providing the most helpful and trustworthy pregnancy and parenting information in the world. When creating and updating content, we rely on credible sources: respected health organizations, professional groups of doctors and other experts, and published studies in peer-reviewed journals. We believe you should always know the source of the information you're seeing. Learn more about our editorial and medical review policies.

Cameron EL. 2007. Measures of human olfactory perception during pregnancy. Chemical Senses. a new window [Accessed December 2021]

Cameron EL. 2014. Pregnancy and olfaction: A review. Frontiers in Psychology. a new window [Accessed December 2021]

Cameron EL. 2014. Pregnancy does not affect human olfactory detection thresholds. Chemical Senses. a new window [Accessed December 2021]

Cleveland Clinic. 2019. What's That Smell? All You Need to Know About Hyperosmia. a new window [Accessed December 2021]

Ahmed M, Hwang JH, et al. Safety Classification of herbal medicines used among pregnant women in Asian countries: a systematic review. BMC Complementary and Alternative Medicine 17, Article number: 489 (2017) [Accessed December 2021]

Stephanie Watson
Stephanie Watson is a freelance health and lifestyle writer based in Rhode Island. When she’s not busy writing, Watson loves to travel, try new cuisines, and attend as many concerts, shows, and plays as she can fit into her busy schedule.