Are Smell Aversions Linked to Morning Sickness?

By OBGYN Dr. Kenosha Gleaton

Pregnancy can cause a wide range of interesting symptoms. The many hormonal and physical changes occuring in the body result in morning sickness, fatigue, increased urination, and for some people, smell aversions.

What Are Smell Aversions?

Smell aversions refer to gross, overwhelming, or bothersome odors that many will notice during pregnancy or with certain medical conditions. Smell aversions can be related to food, environment, chemicals, people, animals, objects, and more. Over 75% of pregnant people report experiencing some sort of abnormal smell or taste perception. [1] Smell sensitivity is the most common during early stages of pregnancy, occurring in about 67% of study respondents.

[1] Increased sensitivity to smell is also known as hyperosmia. Hyperosmia can occur randomly, and can be associated with conditions such as migraine headaches, epilepsy, pregnancy, and more. [2] Hyperosmia is not always associated with “bad” smells, but a heightened sense of smell in general.

What Causes Smell Aversions?

There isn’t a confirmed cause of smell aversions or hyperosmia. Some data suggests that genetics, underlying conditions, hormonal changes, and even psychological distress may play a role in odor sensitivity. [2-4]

When considering smell aversions linked to pregnancy, the presence of human chorionic gonadotropin (hCG) seems to be correlated to the onset of morning sickness and an altered sense of smell. [5] Some researchers also believe that heightened sense of smell during pregnancy is a way of protecting the body from danger. Smell plays a primary role in survival by detecting potential threats (spoiled food, smoke, chemicals or gas). [4] Experiencing smell aversions or differences in your sense of smell may be partly caused by your body attempting to protect yourself and your pregnancy. [4-5]

Do Smell Aversions Cause Morning Sickness?

Smell aversions often occur at the same time as morning sickness, with some studies attempting to determine if one causes the other. Both are present in the early stages of pregnancy and tend to resolve by the last trimester. [5] A lot of research can connect increased olfactory sensitivity to nausea and vomiting, however classical conditioning could also explain the relationship between the two. [5] For example, experiencing morning sickness while eating a certain food may then trigger someone to have a smell aversion to that food.

We really aren’t sure what exactly causes morning sickness, although a lot of research does point to increased levels of hormones during early pregnancy. [3] These hormonal changes may also play a role in the heightened sense of smell. [3,5] The short answer is that there isn’t a confirmed cause of pregnancy nausea or smell aversions at this time, but a considerable amount of research does lead us to believe they are connected somehow.

Sense of Smell and Food Aversions

Smell aversions can impact many other symptoms and senses, including food aversions and cravings. Smell and taste are closely linked as both the taste buds and olfactory nerves communicate to the brain in order to recognize flavors and tastes. [6] Research suggests that hormones also play a role in food aversions. [7] The relationships observed between taste, smell, nausea, and hormones, lead many to believe that all three are connected and can impact one another.

How to Manage an Increased Sense of Smell During Pregnancy

Experiencing heightened olfactory sensitivity has its pros and cons. It can be difficult to go about your day when there are so many potential triggers that are out of your control. Here are a few ways to manage smell aversions during pregnancy.

Increase Airflow

Depending on where you are and what smells are troubling you, keeping consistent airflow may help. If possible, you can open a window, turn on a fan, or even look into an air purifier. This will help circulate the air and hopefully disrupt any lingering smells.

Saline Washes

Using nasal sprays or saline washes (with your healthcare provider’s approval) is a great way to keep the nose healthy and moist. [2] This is a treatment sometimes recommended to people dealing with hyperosmia. [2]

Wear a Mask

If necessary, you can use a mask to help block strong odors. This may be a useful way to limit potential triggers when outside of your home.

Avoid Triggers

This may seem obvious, but you should remove any unwanted or bothersome smells from your home and personal area when possible. Common triggers for many people include smelly foods such as fish, eggs, and meat. [3,6,7] Some smell aversions can even make “good” smells difficult to be around. If air fresheners, detergent, perfume, etc. are bothering you, you can switch to unscented alternatives or stop using these products until your senses return back to normal.

Lean on Others

You shouldn’t have to suffer through a difficult symptom by yourself. Let your coworkers, family, and friends know what some of your triggers are and what, if anything, they can do to support you. This could include not wearing perfumes, avoiding making or eating certain foods around you, helping to complete certain chores around the house, and so on.

Managing Nausea and Vomiting When Experiencing Smell Aversions

If you are experiencing smell aversions, you may also be managing morning sickness. Smell plays a large role in taste and nausea and may make your morning sickness or food aversions worse. [6] There is no cure to stop nausea and vomiting from occurring, but there are ways to manage it. [3] Using the methods listed above for managing smell aversions can be very helpful in reducing potential triggers. It’s also recommended that those experiencing morning sickness alter their lifestyle and diet to help reduce nausea and vomiting. [3] This includes adjusting meal times as necessary, avoiding smelly, spicy, fried, or acidic foods, and incorporating ginger and vitamin B6 into your diet. [3,8]

Consider incorporating our vitamin B6 and ginger gummies for nausea as a convenient and effective option to help alleviate morning sickness symptoms during your pregnancy. It’s important to consume an adequate amount of electrolytes, water, vitamins, and minerals during pregnancy, especially if you’re having a difficult time eating balanced meals or keeping food down. [3] Taking a prenatal vitamin may help reduce the risk of severe morning sickness and ensures you’re getting all the vital nutrients you need. [3]

When to See a Healthcare Provider

If your smell aversions or nausea are interrupting your daily life or impacting your ability to eat, you should see a healthcare provider. Altered senses are common during pregnancy, but can also be a sign of an underlying condition. [6] If you’re concerned about any of your symptoms or have any questions about managing or treating food aversions, smell aversions, or morning sickness, you should reach out to your healthcare provider.

Natalist is Here to Help

There is a long list of symptoms that you may experience during pregnancy. Morning sickness, food aversions, smell aversions, and more can all be managed with the right products and guidance. Support your body during pregnancy with Natalist products such as prenatal vitamins, electrolyte drinks, nausea relief products, and more. You can read more about pregnancy on the Natalist blog.

References:

1. Nordin S, Broman DA, Olofsson JK, Wulff M. A longitudinal descriptive study of self-reported abnormal smell and taste perception in pregnant women. Chem Senses. 2004;29(5):391-402. doi:10.1093/chemse/bjh040
2. What’s That Smell? What You Need to Know About Hyperosmia. Cleveland Clinic Health Essentials. November 12 2019. URL.
3. Morning sickness: Nausea and vomiting of pregnancy. ACOG. URL. Published May 2020. Accessed May 23, 2023.
4. Houghton DC, Howard SL, Uhde TW, Paquet C, Schlosser RJ, Cortese BM. Odor sensitivity impairment: a behavioral marker of psychological distress?. CNS Spectr. 2019;24(4):404-412. doi:10.1017/S1092852918001177
5. Cameron EL. Pregnancy and olfaction: a review. Front Psychol. 2014;5:67. Published 2014 Feb 6. doi:10.3389/fpsyg.2014.00067
6. Fried, M. Overview of Smell and Taste Disorders. Merck Manual. May 2023. URL.
7. Yalew A, Tekle Silasie W, Anato A, Fikrie A. Food aversion during pregnancy and its association with nutritional status of pregnant women in Boricha Woreda, Sidama Regional State, Southern Ethiopia, 2019. A community based mixed crossectional study design. Reprod Health. 2021;18(1):208. Published 2021 Oct 18. doi:10.1186/s12978-021-01258-w
8. Weir SBS, Akhondi H. Bland Diet. [Updated 2022 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538142/