Rib Pain During Pregnancy: What Could Be Causing It and When to Get Help

What Is Actually Happening to Your Ribs During Pregnancy?

Your rib cage is not a fixed structure. During pregnancy, rising progesterone relaxes the ligaments that connect your ribs to your sternum and spine, and your uterus pushes your diaphragm upward by approximately 4 centimeters by the third trimester. The result is a measurable outward flare of the lower ribs that can cause anything from a dull ache to sharp, stabbing discomfort, especially on your right side where the liver sits.

This remodeling is necessary. Your body needs to accommodate a growing baby, placenta, and amniotic fluid while still letting your lungs expand. The trade-off is real discomfort for many women.

How Your Rib Cage Changes Trimester by Trimester

First trimester (weeks 1-13). Rib pain this early is unusual. If you feel it, consider musculoskeletal causes unrelated to uterine size, or, rarely, an ectopic pregnancy pressing on adjacent structures before rupture. Ectopic pregnancy affects approximately 1 in 50 pregnancies and is a medical emergency.

Second trimester (weeks 14-27). As your uterus rises above the navel, typically around week 20, it begins pressing into your lower rib cage. You may notice a pressure or bruised sensation under your bra line, often worse on the right side. Your intercostal muscles, the thin muscles between each rib, begin to stretch.

Third trimester (weeks 28-40). This is when most women report the worst rib pain. Your baby's feet or knees may press directly into your lower ribs. The diaphragm is at maximum elevation. Rib cage circumference increases an average of 10 to 15 centimeters across pregnancy, meaning the ligaments and muscles have been under sustained stretch for months.

Mechanical and Musculoskeletal Causes (The Most Common)

Most rib pain in pregnancy is mechanical. It hurts, but it is not dangerous.

Uterine Expansion and Diaphragm Elevation

Your uterus reaches the level of your navel by about week 20 and your xiphoid process (the bottom tip of your sternum) by around week 36. The diaphragm rises approximately 4 cm above its pre-pregnancy position, compressing the lower intercostal spaces. Women carrying multiples or with polyhydramnios experience this earlier and more intensely.

Baby Position and Fetal Movement

In the third trimester, your baby's feet are often lodged under your ribs, particularly if the baby is in a head-down (cephalic) position. A swift kick or sustained pressure from a knee or foot against the lower right rib cage is one of the most reported causes of sudden, sharp rib pain.

Changing position, doing a hands-and-knees stretch, or gently nudging the baby can shift the pressure. If your baby is persistently breech after 36 weeks, ACOG recommends discussing external cephalic version, which may also relieve chronic rib pressure.

Intercostal Muscle Strain

The muscles running between each rib are under prolonged, progressive stretch. Coughing, sneezing, or a sudden twist can strain them acutely. The pain is usually sharp, one-sided, worsens with a deep breath or movement, and reproduces when you press on the specific rib. This is called intercostal myalgia and is managed with rest, gentle stretching, and acetaminophen.

Rib Flare

"Rib flare" describes the outward spreading of the lower costal margin. Some women can see and feel their lower ribs protruding more than before pregnancy. The ligament laxity driven by relaxin, a hormone that rises sharply in the first trimester and remains elevated throughout, is primarily responsible. Relaxin levels in pregnancy are 10-fold higher than in the luteal phase of a non-pregnant cycle, explaining why ligament-related pain is so much more pronounced.

Costochondritis and Tietze Syndrome

Inflammation at the junction where the ribs meet the cartilage connecting them to the sternum can occur in pregnancy and produces anterior chest and rib pain that worsens with palpation. It is not dangerous but can feel alarming because the pain sometimes radiates to the breast or shoulder.

Skin and Nerve Causes

Shingles (Herpes Zoster)

Pregnancy modestly suppresses cellular immunity, making reactivation of varicella-zoster virus slightly more likely. Shingles typically causes a burning or shooting pain along one dermatomal band, often following a rib, before a blistering rash appears. If you suspect shingles, contact your obstetric provider the same day. Oral acyclovir is considered safe in pregnancy.

Intercostal Neuralgia

As the rib cage expands, intercostal nerves can become compressed or irritated, producing a shooting, electric, or burning pain that wraps from your back around one side of your torso. It is more common in the third trimester and usually resolves after delivery.

Gastrointestinal Causes

Acid Reflux and Hiatal Hernia

Progesterone relaxes the lower esophageal sphincter, and the elevated diaphragm further displaces the stomach. Heartburn affects up to 80% of pregnant women at some point, and a small hiatal hernia can develop or worsen. The pain is typically substernal or epigastric but can radiate into the lower rib area and is worse after meals or lying flat.

Gallstones and Biliary Colic

Estrogen increases cholesterol saturation in bile, and progesterone slows gallbladder emptying. Pregnancy is a significant risk factor for gallstone formation. Gallstones develop in approximately 5-12% of women during pregnancy. Biliary colic produces sharp, cramping pain in the right upper quadrant and right lower rib cage, often after a fatty meal, and may radiate to the right shoulder. Ultrasound is the first-line diagnostic tool and is safe in pregnancy.

Constipation

Severe constipation can cause referred discomfort into the right or left lower rib area, particularly if stool is impacted in the hepatic or splenic flexure of the colon. It is rarely confused with the more serious causes once a bowel history is taken, but it is worth mentioning because it is so common in pregnancy.

Serious Causes You Must Not Miss

This section covers causes that require urgent or emergent evaluation. Read it carefully.

HELLP Syndrome

HELLP stands for Hemolysis, Elevated Liver enzymes, and Low Platelets. It is a severe variant of preeclampsia and one of the most dangerous conditions of the second half of pregnancy. HELLP syndrome affects 0.5-0.9% of all pregnancies and 10-20% of cases of severe preeclampsia.

The classic presentation includes right upper-quadrant or epigastric pain (often described as a deep, severe ache under the right ribs), nausea, vomiting, headache, and visual disturbances. Blood pressure may be elevated but is not always dramatically so. Maternal mortality from HELLP can reach 1-3% if diagnosis is delayed.

Call your provider immediately or go to an emergency department if:

• You have right upper-quadrant rib pain AND a headache that will not go away
• You have visual changes (blurring, flashing lights, blind spots)
• Your blood pressure reading at home is >140/90 mmHg
• You feel generally unwell alongside the rib pain

ACOG Practice Bulletin 222 on Gestational Hypertension and Preeclampsia describes HELLP as a reason for expedited delivery regardless of gestational age in severe cases.

Intrahepatic Cholestasis of Pregnancy (ICP)

ICP is a liver condition specific to pregnancy in which bile acids build up in the bloodstream. ICP affects approximately 1-2% of pregnancies in the United States, with higher rates in women of South American or Scandinavian ancestry and in twin pregnancies.

The hallmark symptom is intense, often unbearable itching, typically starting on the palms and soles and spreading to the torso, worse at night. Right-sided rib pain or right upper-quadrant discomfort accompanies the itching in many cases. ICP carries an increased risk of stillbirth, preterm birth, and meconium staining of amniotic fluid. Serum bile acid levels above 40 micromol/L are associated with significantly higher stillbirth risk, per a 2021 study published in The Lancet.

Ursodeoxycholic acid (ursodiol) at 10-15 mg/kg/day is the standard treatment and is generally considered safe in pregnancy, though it does not fully normalize bile acids in all patients.

Pulmonary Embolism (PE)

Pregnancy increases VTE (venous thromboembolism) risk approximately 4-5 fold compared to non-pregnant women of the same age, and this risk peaks in the first 6 weeks postpartum. A pulmonary embolism can cause pleuritic chest or rib pain, shortness of breath, rapid heart rate, and, in severe cases, collapse. Any sudden onset of sharp rib or chest pain with difficulty breathing in pregnancy warrants emergency evaluation. CT pulmonary angiography, the diagnostic gold standard, is performed in pregnancy when PE is clinically suspected, as the risk of an undiagnosed PE far exceeds radiation exposure from the scan.

Pneumothorax and Pneumonia

Spontaneous pneumothorax is rare but can occur in young women, including pregnant ones. Sharp, one-sided chest or rib pain with sudden-onset shortness of breath and decreased breath sounds on one side is the typical picture. Pregnancy-related pneumonia, most often from influenza or community-acquired bacterial infection, can produce pleuritic rib pain alongside fever and cough.

Diagnosing the Cause of Your Rib Pain in Pregnancy

Your provider will use a combination of history, physical exam, and targeted tests. Ultrasound is the preferred imaging modality because it uses no ionizing radiation.

What to Expect at Your Appointment

Your clinician will ask about the location (right, left, front, back), character (sharp, dull, burning, pressure), onset (sudden versus gradual), triggers (movement, breathing, meals, position), and associated symptoms (itching, nausea, headache, swelling, fever, shortness of breath).

For mechanical causes, the diagnosis is usually clinical. For anything suggesting HELLP or cholestasis, expect blood work: a complete blood count (CBC), liver function tests (LFTs), uric acid, and serum bile acids. Blood pressure will be measured. Fetal monitoring may follow if there is any concern about fetal wellbeing.

The table below summarizes the key distinguishing features across the most common causes, organized by urgency.

| Cause | Location | Key Feature | Urgency | |---|---|---|---| | Uterine/fetal pressure | Right or bilateral lower ribs | Worse in third trimester, relieved by position change | Routine | | Intercostal strain | One side, follows rib | Reproduces on palpation | Routine | | Heartburn/GERD | Substernal, upper abdomen | Worse after meals, lying flat | Routine | | Gallstones | Right upper quadrant, right shoulder | After fatty meals, colicky | Urgent (same-day call) | | Shingles | One dermatomal band | Burning, precedes rash | Urgent (same-day call) | | Cholestasis (ICP) | Right upper quadrant | Intense palm/sole itching | Urgent (same-day call) | | HELLP syndrome | Right upper quadrant, epigastric | Hypertension, headache, vomiting | Emergency (911 or ER) | | Pulmonary embolism | Chest/rib, one-sided | Shortness of breath, rapid heart rate | Emergency (911 or ER) |

Treatment and Relief: What Actually Works

Safe Non-Drug Approaches

Positional changes are the first tool. Sitting upright, leaning slightly forward, or doing a hands-and-knees stretch (cat-cow) can shift uterine weight off the diaphragm within minutes. Sleeping propped up on your left side offloads the liver and may reduce right-sided rib discomfort.

A warm compress (not hot) applied to the affected area for 15-20 minutes can ease intercostal muscle tension. Warm baths serve the same purpose.

Prenatal yoga and swimming are supported by a 2015 Cochrane review that found exercise interventions modestly reduced pregnancy-related musculoskeletal pain with no evidence of harm to mother or baby when done appropriately.

Maternity support bands can redistribute abdominal weight and reduce the pull on intercostal muscles in the third trimester.

Acetaminophen (Paracetamol)

Acetaminophen is the only oral analgesic recommended for routine use in pregnancy. ACOG and the FDA both note that occasional use at standard doses (325-650 mg every 4-6 hours, maximum 3,000 mg/day in pregnancy) is generally considered acceptable for musculoskeletal pain. Avoid NSAIDs (ibuprofen, naproxen) after 20 weeks. The FDA issued a 2020 warning that NSAID use from 20 weeks onward may cause fetal renal dysfunction and oligohydramnios. Before 20 weeks, NSAIDs carry a possible association with miscarriage and early closure of the ductus arteriosus, so most practitioners advise avoiding them throughout pregnancy.

Opioids require specialist oversight and carry risks of neonatal opioid withdrawal syndrome. They are not appropriate for routine musculoskeletal rib pain in pregnancy.

Physical Therapy

A pelvic floor physical therapist or women's health physical therapist trained in obstetric care can assess rib alignment, teach intercostal stretching, and use manual therapy techniques that are safe in pregnancy. Referral is appropriate when positional changes and acetaminophen are not providing adequate relief.

Condition-Specific Treatments

• Heartburn. Calcium carbonate antacids, H2-blockers (famotidine), and, when necessary, proton pump inhibitors are used in pregnancy with reasonable safety profiles.
• Gallstones. Dietary fat restriction reduces biliary colic frequency. Symptomatic gallstones causing cholecystitis or obstruction may require laparoscopic cholecystectomy, which is safest in the second trimester if surgery cannot be deferred.
• ICP. Ursodiol at 10-15 mg/kg/day is the standard medication; delivery is typically planned at 36-37 weeks for severe ICP (bile acids >100 micromol/L).
• HELLP. The definitive treatment is delivery. Corticosteroids may be given to accelerate fetal lung maturity if gestational age allows a brief window.

Who Gets Rib Pain in Pregnancy and Who Is at Higher Risk

Certain factors make rib pain more likely or more severe.

Higher Risk for Mechanical Rib Pain

• Carrying multiples (twins, triplets)
• Polyhydramnios (excess amniotic fluid)
• Tall babies or babies in a persistently breech position
• Short maternal stature (the uterus has less vertical room)
• Previous rib fractures or scoliosis altering rib cage mechanics

Higher Risk for Serious Causes

• Personal or family history of preeclampsia or HELLP
• Chronic hypertension or pre-existing kidney disease
• Obesity (BMI >30 at conception)
• Multifetal gestation
• Personal or family history of ICP or cholestasis in a prior pregnancy
• South American or Scandinavian ancestry (ICP risk)
• History of deep vein thrombosis, clotting disorder, or prolonged immobility (PE risk)

Rib Pain After Delivery: What Changes Postpartum

Rib pain typically improves within days to weeks after delivery as the uterus involutes and the diaphragm descends. However, a few situations deserve attention postpartum.

HELLP syndrome can develop or worsen in the first 48 hours after delivery. Right upper-quadrant pain, hypertension, or abnormal labs in that window need immediate evaluation, not a "wait and see" approach.

If you had ICP, bile acid levels should normalize within 4-6 weeks postpartum. Women with ICP have an elevated risk of recurrence in subsequent pregnancies (reported recurrence rates range from 45-70%), and some evidence suggests a modestly increased lifetime risk of hepatobiliary disease. Tell any future obstetric provider about your history.

Persistent rib pain beyond 6-8 weeks postpartum, especially in a breastfeeding woman, may reflect continued ligament laxity driven by relaxin (which remains elevated during lactation) or a musculoskeletal issue requiring physiotherapy.

A Note on Evidence Gaps in Pregnant Women

Pregnant women are systematically excluded from most randomized clinical trials. Much of what we know about pain treatment in pregnancy comes from observational data, case series, or extrapolation from non-pregnant populations. The NIH Task Force on Research Specific to Pregnant Women and Lactating Women has repeatedly called for better inclusion of pregnant people in clinical research. This means that for several of the conditions described here, particularly the optimal analgesic dosing and duration, the evidence base is weaker than we would like. Your clinician should account for this when discussing your options, and you have every right to ask what is well-studied versus what is extrapolated.

When to Seek Care: A Practical Decision Guide

Call 911 or go to the emergency department now if you have:

• Sudden severe rib or chest pain with shortness of breath or rapid heart rate
• Right upper-quadrant pain with a severe headache, visual changes, or blood pressure >140/90
• Suspected collapse or syncope

Call your OB or midwife the same day if you have:

• Right-sided rib pain with intense itching, especially on your palms or soles
• Right upper-quadrant pain after a fatty meal with nausea or right shoulder pain
• Any new rib pain accompanied by fever, cough, or feeling generally unwell
• Rib pain that wakes you from sleep and does not improve with positional change

Schedule a routine appointment if you have:

• Dull, diffuse lower rib discomfort that worsens as the day goes on
• Rib pain clearly related to fetal movement or position
• Rib pain that improves with positional changes and responds to acetaminophen
• Anterior chest rib pain that is tender to palpation (possible costochondritis)