Halitosis or Bad Breath During Pregnancy

Bad breath during pregnancy is a very common symptom and can be quite uncomfortable. Find out why it appears and what to do to avoid it.
Halitosis or Bad Breath During Pregnancy

Last update: 11 October, 2022

Having bad breath during pregnancy is a typical discomfort of this stage and several factors contribute to it. Among them, the physiological and adaptive changes of pregnancy.

Here, we’ll explain why it happens and what you can do to control this oral condition.

Bad breath

Bad breath, also known as halitosis, is the unpleasant odor that comes out of the mouth. This problem can affect anyone, but it’s something particularly common in pregnancy.

Most of the time, this unpleasant odor comes from the oral cavity itself, either due to the action of the bacteria that live there or due to the decrease in the production of saliva.

During the night, the normal salivary flow decreases and this favors the proliferation of the germs that cause bad breath. This type of halitosis usually disappears over time, after eating something or brushing your teeth.

In other cases, halitosis occurs as a consequence of the hormonal changes of pregnancy that affect the normal conditions of the mouth. And although it’s a harmless condition, it can be very embarrassing for pregnant women.

Symptoms of bad breath during pregnancy

Many pregnant women with halitosis may not be fully aware of the problem. Although it’s not perceived through smell, bad breath can manifest itself through other symptoms:

  • A bad taste in the mouth
  • A persistent bitter taste
  • Dry mouth
  • The presence of a thick white coating on the surface of the tongue
  • Throat discomfort
  • The accumulation of bacterial plaque on tooth surfaces
  • Tartar presence
  • Large and deep cavities
  • Swollen and bleeding gums

If a pregnant woman detects some of these symptoms, it’s best to go to a trusted dentist for help.

A woman with bleeding gums.

The causes of bad breath during pregnancy

As we already mentioned, the changes that occur during pregnancy can be the cause of bad breath. We’ll explain them below.

Hormonal changes

The fluctuation of the mother’s hormonal levels favors the growth and development of the baby, but they affect the entire body of the pregnant woman, including her oral cavity.

Estrogens and progesterone favor the proliferation of microorganisms and the accumulation of bacterial plaque on the teeth. If it’s not removed properly through dental hygiene, it can cause an unpleasant odor in the mouth, in addition to other complications in oral health.


The consumption of water during pregnancy is essential, as inadequate hydration can cause health problems in the mother and the fetus.

The lack of saliva in the mouth, known as xerostomia, favors the accumulation of food debris and the bacterial fermentation of the same. Therefore, keeping an oral cavity moist and with a good salivary flow avoids an ugly smell in the pregnant woman’s mouth.

Nausea and vomiting

Nausea, vomiting, and slow digestion are fairly common symptoms among pregnant women. The reflux of undigested food and stomach acids also causes bad breath.

Despite the discomfort that brushing can cause during this stage, it’s essential for pregnant women not to neglect their oral hygiene. Cleaning your mouth after vomiting helps remove bacteria, acid, and odor.


The consumption of certain foods, such as garlic, onion, or coffee, favors this unpleasant symptom. Just the same, in these cases, bad breath is usually temporary and disappears after a few hours.

During pregnancy, it’s common for women to change their eating habits and crave unhealthy foods. Therefore, maintaining a diet rich in sugar or eating frequently favors the accumulation of bacterial plaque, halitosis, and the development of cavities.

Oral problems

During pregnancy, increased gingival blood flow causes the gums to swell, bleed, and hurt. This condition is known as gingivitis and is also associated with bad breath during pregnancy.

It’s important not to neglect tooth brushing despite the discomfort, as the accumulation of tartar and the evolution to periodontitis can worsen the unpleasant mouth odor.

Poor oral hygiene, dry mouth, and unhealthy eating habits increase the risk of tooth decay. In turn, the advanced stages of this disease favor the accumulation of food remains in the dental holes and lead to oral infections.

Medical conditions

There are some systemic pathologies that cause bad breath or a characteristic mouth odor. Diabetes, throat infections, sinusitis, airway problems, and diseases of the digestive system are some examples of them.

It’s important to pay attention to the smell of the mouth and consult your obstetrician if you notice any significant change in it during this stage.

Tips to avoid bad breath during pregnancy

A pregnant woman brushing her teeth.

As you’ve seen, bad breath is a fairly common symptom during pregnancy. However, there are several practices to keep your mouth healthy and thus reduce the bad smell.

Here are some tips to avoid bad breath during pregnancy :

  • Maintain proper oral hygiene: Brush your teeth and tongue correctly with fluoride paste, dental floss, and alcohol-free mouthwashes.
  • Ensure a healthy diet: Eat a healthy and varied diet to accompany a healthy pregnancy. Avoid sugary, acidic foods and those with a strong odor.
  • Drink water frequently: Maintain an adequate state of hydration to prevent diseases. It’s important to drink enough natural water every day and avoid sugary drinks or sodas.
  • Attend all dental visits: Visit the dentist periodically during pregnancy in order to detect and treat any problems early. Ideally, visit the dentist once a trimester and in the case of any emergency.

A bad smell in the mouth in pregnancy can be one of the many normal changes of this stage. However, it’s a rather embarrassing symptom, which can be prevented and improved with proper dental care.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

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This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.