Swollen gums are almost always a sign of inflammation, and the most common trigger is bacterial plaque building up along the gumline. But plaque isn’t the only explanation. Hormonal changes, certain medications, nutritional deficiencies, and chronic conditions like diabetes can all cause gums to puff up, redden, and bleed. Understanding the cause is the first step toward getting rid of the swelling.
Plaque Buildup and Early Gum Disease
The number one reason gums swell is gingivitis, the earliest stage of gum disease. When plaque (a sticky film of bacteria) sits on your teeth for too long, it irritates the gum tissue and triggers an inflammatory response. Your gums turn red, feel tender, and may bleed when you brush or floss. Gingivitis is reversible with better oral hygiene, and it doesn’t involve any bone loss.
If gingivitis goes untreated, it can progress to periodontitis. At this stage, the inflammation attacks the soft tissue and bone that hold your teeth in place. The pockets between your teeth and gums deepen, sometimes reaching more than a centimeter. Healthy gums have pocket depths of 3 millimeters or less. Once pockets reach 5 millimeters or more, there’s a real risk of permanent attachment loss and even jawbone breakdown that exposes tooth roots.
Hormonal Changes During Pregnancy and Puberty
If you’re pregnant and noticing swollen, bleeding gums for the first time, hormones are the likely culprit. Estrogen and progesterone levels rise dramatically during pregnancy. By the third trimester, progesterone reaches about 10 times its normal level, and estrogen climbs to roughly 30 times its usual concentration. These surges aren’t just background noise for your gums. They increase blood flow to gum tissue, amplify the body’s inflammatory response to plaque bacteria, and boost the production of signaling molecules that drive swelling.
The result is what’s often called pregnancy gingivitis. Your gums may swell and bleed even if your brushing habits haven’t changed, because the same amount of plaque now provokes a much stronger reaction. Similar (though less dramatic) shifts happen during puberty and at certain points in the menstrual cycle, which is why some people notice their gums feeling puffy or tender around their period.
Medications That Cause Gum Overgrowth
Certain prescription drugs cause the gum tissue itself to grow larger, a condition called gingival overgrowth. Three drug classes are the main offenders:
- Seizure medications: Phenytoin is the most common cause. Roughly 50% of adults taking it develop gum enlargement.
- Immunosuppressants: Cyclosporine, frequently prescribed after organ transplants, causes gum overgrowth in about 53% of kidney transplant patients and around 30% of users overall.
- Blood pressure medications (calcium channel blockers): Nifedipine and amlodipine are the most frequently linked. About 20% of people on nifedipine experience it.
If your gums started swelling after beginning a new medication, that’s a strong clue. The overgrowth typically begins between the teeth and can make cleaning even harder, which compounds the problem. Your dentist and prescribing doctor can discuss whether switching medications is an option.
Vitamin C Deficiency
Severely low vitamin C levels cause scurvy, and swollen, bleeding gums are one of its hallmark signs. Early symptoms like fatigue and irritability appear when blood levels of vitamin C drop below a certain threshold, but the classic gum problems, along with bruising and abnormal hair growth, show up once levels fall below 0.2 mg/dL. Scurvy also causes gum recession and increases the risk of cavities.
Full-blown scurvy is uncommon in developed countries, but it does still occur, particularly in people with very restrictive diets, those experiencing food insecurity, and heavy smokers (smoking depletes vitamin C). If your diet has been consistently low in fruits and vegetables and your gums are swollen alongside unusual bruising or fatigue, vitamin C deficiency is worth investigating.
Diabetes and Blood Sugar Control
Diabetes and gum disease have a two-way relationship. Persistently high blood sugar ramps up inflammatory signaling in gum tissue, pushing immune cells toward a destructive mode while suppressing the cells responsible for tissue repair. High glucose also shifts the balance of bacteria in your mouth toward more harmful species, making gum infections more likely and harder to control.
On top of that, chronic high blood sugar causes changes at the genetic level in gum cells, increasing the production of enzymes that break down the connective tissue holding teeth in place. This is why people with poorly controlled diabetes are significantly more prone to periodontitis, and why managing blood sugar is a critical part of managing gum health.
Braces and Orthodontic Appliances
Fixed braces are notorious for causing swollen gums. Brackets, bands, and wires create small ledges and tight spaces where plaque accumulates easily and is difficult to remove. The cement used to bond brackets and any excess adhesive around the edges can also irritate gum tissue directly. On top of mechanical irritation, braces change the overall environment inside the mouth, limiting saliva’s ability to wash bacteria away and encouraging colonization by more aggressive periodontal bacteria.
If you have braces and your gums are swollen, stepped-up cleaning is essential. Interdental brushes (the small bristled picks designed to fit between teeth) are more effective than floss alone at reducing gum inflammation and plaque, according to multiple analyses. Threading floss under wires is still worthwhile, but interdental brushes should be your primary tool for getting around brackets.
Other Common Triggers
A few other situations commonly cause gum swelling. A dental abscess, which is a pocket of infection at the root of a tooth or in the gum tissue, can produce rapid, localized swelling that may be accompanied by throbbing pain and fever. Canker sores on the gums, ill-fitting dentures, and aggressive brushing with a hard-bristled toothbrush can all cause inflammation too. Smoking is another major factor: it reduces blood flow to gum tissue, impairs healing, and increases the risk of gum disease at every stage.
What Helps Swollen Gums
For most people, swollen gums improve with consistent, thorough cleaning. Brushing twice a day with a soft-bristled brush, using interdental brushes or floss daily, and rinsing with warm salt water can reduce mild inflammation within a week or two. Interdental brushes in particular outperform floss and wooden sticks for reducing both plaque and gingival inflammation.
If swelling doesn’t improve with home care, or if your gums bleed regularly, professional cleaning is the next step. A deep cleaning procedure called scaling and root planing removes hardened plaque (tarite) from below the gumline and smooths the root surfaces so gums can reattach. Studies show this reduces pocket depth by about 0.7 to 1.1 millimeters on average, which can be enough to shift pockets from the disease range back toward health.
Signs That Need Urgent Attention
Most gum swelling is not an emergency, but certain symptoms alongside it signal something more serious. Difficulty breathing, swallowing, or opening your mouth, swelling that spreads to your face or eye area, sudden vision problems, or a fever with significant mouth swelling all warrant immediate care. These can indicate a spreading infection that needs treatment the same day.