Armpit Pain During Second Trimester | Causes And Relief

The middle stretch of pregnancy often brings more energy, so a new ache high in the side of the chest or under the arm can feel alarming. Many people wonder whether armpit pain in the second trimester means breast disease, infection, or something that could harm the baby.

Most of the time this symptom comes from normal breast changes, lymph nodes that react to illness or vaccines, or simple strain from daily life.

Armpit Pain During Second Trimester Causes And Normal Changes

By weeks thirteen to twenty seven, hormones encourage breast tissue to grow and prepare for feeding. That tissue often extends into the armpit, and the added weight can lead to a heavy, pulling ache on one or both sides. At the same time, fluid shifts and rising blood volume leave the whole underarm area more prone to swelling.

The table below sets out frequent reasons for underarm pain around the second trimester and the patterns that usually go with each one.

Cause	Typical Sensation	Usual Pattern
Axillary breast tissue	Fullness, heaviness, dull ache	Builds over days or weeks as breasts enlarge
Swollen lymph nodes	Small tender lump	May follow a cold, vaccine, or skin irritation
Muscle strain	Soreness that flares with movement	Linked to lifting, exercise, or sleeping position
Poor bra fit	Pinching, rubbing under the arm	Worse later in the day or with one bra style
Skin irritation or rash	Burning, itching, redness	Can appear after shaving or new deodorant
Blocked milk ducts	Firm tender area that eases with warmth	More common later in pregnancy and near birth
Less common serious causes	Hard fixed lump, persistent pain	Does not settle, may spread or change the skin

Hormonal Breast Changes And Axillary Tissue

Breast tissue can extend into the underarm, called axillary or accessory breast tissue. As ducts and glands grow in pregnancy this extra tissue can swell, feel lumpy, and grow tender, especially late in the day or when lying on one side.

The HSE guide to breast changes in pregnancy explains that new lumps linked to this tissue often feel soft and mobile and tend to mirror tenderness in the main part of the breast. Even so, any lump that seems new or different needs to be checked at an antenatal or breast clinic visit.

Swollen Lymph Nodes Under The Arm

Lymph nodes sit in chains under each arm and help the body react to infection and injury. During pregnancy they may enlarge after a viral illness, gum or tooth trouble, skin infection, or a recent vaccine in the same arm. These nodes usually feel like small beans under the skin that move a little when pressed.

Most reactive nodes shrink over a few weeks and do not cause strong pain. Nodes that grow larger, feel hard or fixed, appear on only one side, or come with fever or weight loss deserve medical review without delay.

Muscle Strain, Posture, And Daily Habits

As your bump grows, posture changes and the upper back and chest muscles work harder. Lifting children, carrying shopping on one shoulder, or sleeping with an arm over the head can strain the chest wall and the muscles that run into the armpit.

Muscle based pain often feels like a bruise or pull that flares when you reach overhead, twist, or push up from a chair. It usually settles with rest, gentle stretching, and small changes in how you carry loads through the day.

Why Armpit Pain In Second Trimester Happens And When To Act

Armpit discomfort sends a signal that tissue in that area is under pressure, inflamed, or responding to hormones. Many patterns stay within normal pregnancy change, yet some point toward infection or breast disease that needs fast attention.

The American College of Obstetricians and Gynecologists shares an ACOG overview of body changes during pregnancy that describes how breast size, blood flow, and posture shift across the trimesters. Those same shifts explain a large share of mid pregnancy underarm aches.

Normal Patterns Of Pregnancy Related Armpit Pain

Normal pregnancy linked armpit pain usually appears on one or both sides in line with breast tenderness. The area may feel full or ropey, not rock hard. Symptoms often vary through the day and improve with a change of bra, cooler showers, or a break from shaving and scented products.

When pain eases over one to three weeks, does not wake you from sleep, and does not limit arm movement, it tends to fall in the “expected change” group. Even then, mentioning it at a routine check gives your midwife or doctor the chance to check the area and record a baseline.

Warning Signs That Need Medical Review

Certain features mean armpit pain should be checked without delay. Get urgent advice from your maternity unit or emergency services if you notice:

• A hard, fixed, or rapidly growing lump in the armpit or breast.
• Redness, warmth, or swelling that spreads across the skin.
• Fever, chills, or feeling unwell along with underarm pain.
• Dimpling of the skin, nipple changes, or discharge that is bloody.
• Sudden sharp pain with shortness of breath or chest pain.

These signs can point toward infection, blood clot, or a breast problem such as cancer, all of which need fast assessment. In pregnancy, acting early gives your team more options and helps protect both you and your baby.

Safe Home Relief For Armpit Pain While Pregnant

Once serious causes seem unlikely, comfort becomes the main aim. Gentle steps at home can ease armpit pain during second trimester and cut the chance that the same area flares again later in pregnancy.

Adjusting Positions And Daily Movements

Swap the shoulder that carries bags, keep heavy loads close to the body, and ask for help with lifting when you can. When sitting, rest the forearms on pillows or chair arms so the shoulders can relax instead of creeping upward. Side sleeping often feels better with a pillow under the upper arm so the shoulder does not pull forward.

Cool Packs, Warmth, And Skin Care

A thin cloth wrapped around a cool pack in the armpit for ten to fifteen minutes can lessen swelling and dull aching. Warm showers or a warm compress help tight muscles relax and may ease the feel of full gland tissue. Use clean razors, fragrance free products, and loose breathable fabrics so the skin stays calm; arrange a review if any rash spreads, oozes, or forms open areas.

Choosing Bras That Reduce Underarm Pressure

A bra that once fit well can begin to dig into the underarm as the rib cage widens and breast size changes. Choose wide soft straps and a band that sits level across the back without riding up, and check that underwires rest on the ribs instead of poking into the side of the breast or armpit.

Simple Pain Relief And Safe Medicine Use

Rest, stretching, and cool or warm packs form the base of drug free relief. When discomfort starts to interrupt sleep or daily life, ask your midwife or doctor which pain medicines are allowed for you, follow their dosing advice closely, and call back if pain keeps rising.

Home Measure	How It Helps	When To Stop
Cool packs in short bursts	Lower swelling and dull aching	If numbness, pale skin, or more pain appears
Warm showers or compresses	Relax tight muscles and ease full tissue	If the area grows more red, hot, or throbbing
Changing bra style	Removes pressure from straps and underwires	If no relief after a week or fit still feels wrong
Gentle stretching	Loosens chest and shoulder muscles	If sharp pain shoots down the arm or into the chest
Short rest breaks at work	Limits strain from repeated arm tasks	If pain no longer links to activity patterns
Skin care changes	Reduces shaving rash and product irritation	If rash spreads, blisters, or forms open areas
Clinician approved pain medicine	Helps through flares while other steps work	If dose needed rises or relief no longer lasts

When To See A Doctor About Second Trimester Armpit Pain

Mention any new armpit symptom at routine antenatal visits so your clinician can compare both sides, feel for lumps, and check the nearby breast tissue. Bring a note of when the pain started, what sets it off, and which steps ease it.

Book an earlier review if the pain appears suddenly on one side, grows day by day, comes with redness or streaks, or includes a firm lump that does not soften or shrink. Sudden armpit pain during second trimester paired with shortness of breath, chest pain, or trouble lifting the arm needs emergency care.

Questions To Ask Your Clinician About Armpit Pain

Clear questions help you leave each visit with a plan you trust. You might ask:

• Do you feel any lumps or changes that need imaging or follow up?
• Does my pattern of pain fit with breast growth, lymph nodes, or muscle strain?
• Are there stretches or posture tips you suggest for my stage of pregnancy?
• Which pain medicines, if any, are safe for me right now?
• When should I call again if the pain changes?

With early checks, good information, simple home care, and helpful answers to your questions, most people find that underarm pain in the middle of pregnancy settles or at least stays manageable. Listening to your body and speaking up when something feels off helps keep this busy season of pregnancy safer and more comfortable.