Pregnancy, Hormones and Gum Inflammation: What Actually Changes

Gums that start bleeding during pregnancy surprise a lot of people, particularly anyone who has never had trouble with them before. Nothing has changed about how they brush. The gums have simply started behaving differently.

This is common, it is well understood, and it is usually manageable. It also sits next to one of the most misreported claims in oral health, which we will come to.

What hormones do to gum tissue

Raised levels of oestrogen and progesterone during pregnancy change the way gum tissue responds to the bacterial film that sits on teeth. Blood flow to the gums increases, the small vessels become more permeable, and the inflammatory response to the same quantity of plaque becomes exaggerated.

The practical result is that a standard of cleaning which kept gums healthy before pregnancy may no longer be enough during it. Gums become redder, puffier, more tender, and quicker to bleed when brushed or flossed. This is often called pregnancy gingivitis. It commonly appears in the second trimester and tends to peak in the third.

Two things are worth stressing. First, the trigger is still plaque. Hormones change the response, not the cause, so cleaning still works and works better than anything else available. Second, bleeding gums are a reason to clean the area gently and thoroughly, not to leave it alone. Avoiding a tender spot lets more plaque build up there, which makes the inflammation worse. It is a common and entirely understandable mistake.

Lumps, sickness and enamel

Some people develop a localised red overgrowth on the gum between two teeth, sometimes called a pregnancy epulis. It can bleed easily and look alarming. It is usually harmless and often shrinks or disappears after the birth. It should still be shown to a dentist, both to confirm what it is and to have the area cleaned, since it tends to sit where plaque has been trapped.

Morning sickness introduces a separate problem. Repeated vomiting coats teeth in stomach acid, which softens enamel. Brushing straight afterwards, while the surface is soft, can remove more of that surface than it otherwise would. The usual advice is to rinse the mouth with plain water, or water with a little bicarbonate of soda, and wait about an hour before brushing. Reflux, also common in pregnancy, does something similar more quietly.

Frequent snacking, which many people find necessary in early pregnancy, raises the number of acid exposures across the day. For decay it is the frequency rather than the total amount that matters most.

The preterm birth question, handled honestly

You may have read that gum disease causes premature birth. This claim needs careful handling.

Observational studies have repeatedly found an association between periodontitis in pregnancy and outcomes such as preterm birth and low birth weight. That association is real in the data. But the same confounding problem appears here as everywhere else in this subject: smoking, age, deprivation, poor access to care and existing health conditions all independently raise the risk of both gum disease and difficult pregnancy outcomes.

The stronger test has been done. Randomised trials have treated periodontitis during pregnancy and compared outcomes against usual care. Those trials have consistently shown that periodontal treatment during pregnancy is safe, which is genuinely useful to know. They have generally not shown a reduction in preterm birth. The most reasonable reading of the evidence is that the association is largely explained by shared risk factors rather than by gum disease causing early labour.

We spell this out because the causal version of the claim can leave people feeling responsible for an outcome they did not cause. That is not a small harm. The same distinction between association and causation runs through our piece on gum disease and heart health.

None of this makes gum care in pregnancy unimportant. It is worth doing because inflamed, bleeding, painful gums are worth treating in their own right, and because untreated gum disease progresses. The World Health Organization treats oral disease as a health problem in itself, which is the right framing.

Dental care during pregnancy

Routine dental care during pregnancy is appropriate and encouraged. Some health systems recognise this explicitly: in England, NHS dental treatment is free during pregnancy and for twelve months after the birth. NHS guidance on dental health in pregnancy sets out what is available and what to expect.

Tell the practice that you are pregnant and how far along you are. It affects positioning during longer appointments, the approach to routine imaging, and sometimes the choice and timing of treatment. Non-urgent elective work is often scheduled for after the birth, but urgent treatment and infection should not be postponed. An untreated dental infection is not the safer option.

Gestational diabetes adds another layer, since raised glucose independently affects gum tissue. Our article on diabetes and gum health covers that relationship.

After the birth

Pregnancy gingivitis usually settles within a few months of delivery, as hormone levels return to their previous pattern. If gums stay inflamed, that suggests something beyond the hormonal effect and should be assessed. The months after a birth are also, realistically, when routine self-care slips, so it is worth knowing that in England the free care window still applies through that first year.

This page is general information rather than personal medical advice. Pregnancy care is individual, and anything unusual in your mouth, or any question specific to your circumstances, belongs with your own dentist, midwife or doctor.