Back pain in the third trimester is one of the most common pregnancy complaints, and there are several effective ways to ease it at home. The combination of a shifting center of gravity, loosening ligaments, and weakening abdominal muscles creates a perfect storm for lower back strain. Here’s what actually helps.
Why Your Back Hurts More Now
Your body produces a hormone called relaxin throughout pregnancy, and it peaks in the third trimester. Relaxin loosens the muscles, joints, and ligaments around your pelvis, back, and abdomen to prepare your body for delivery. The trade-off is that this loosening can make you feel unstable and weak in your core, forcing your back muscles to pick up the slack.
At the same time, your growing belly shifts your center of gravity forward. To compensate, you naturally lean back, which compresses the lower spine and strains the muscles along it. Many women also develop some degree of abdominal separation (diastasis recti), where the two sides of the abdominal wall pull apart. This further weakens the core and is directly linked to increased back pain, since those deep abdominal muscles normally help support the spine.
Exercises That Target the Pain
Pelvic tilts are one of the most consistently recommended exercises for third-trimester back pain. Lie on your back with your knees bent, then flatten your lower back against the floor by tightening your abdominal muscles and tilting your pelvis slightly upward. Hold for up to 10 seconds, release, and repeat. This gentle movement strengthens the deep abdominal muscles without putting pressure on the separated tissue, and it directly relieves tension in the lower back.
Focus on exercises that engage the deep core through slow, controlled movements and deep breathing. Avoid crunches, sit-ups, planks, and any movement that causes your belly to bulge or cone outward. These can worsen abdominal separation and ultimately make back pain worse. If you’re unsure whether you’re doing movements correctly, a physical therapist experienced with prenatal care can create a program tailored to where you are in pregnancy.
Walking, swimming, and prenatal yoga (with modifications to avoid poses like downward dog or boat pose) also help by keeping the muscles around your spine active and flexible without overloading them.
Sleep Positions That Reduce Pressure
Side sleeping with your knees bent is the recommended position in the third trimester. Left-side sleeping is generally preferred because it improves blood flow, but either side works for back pain relief. The key addition is pillow placement: put a pillow between your knees to align your spine and reduce hip pressure, and consider a second pillow under your belly or against your lower back for extra support.
Getting out of bed matters too. Instead of sitting straight up (which strains the abdominals and lower back), roll onto your side first and use your arms to push yourself up. This small change can make a noticeable difference, especially if you have any abdominal separation.
Heat Therapy
A heating pad applied to your lower back is safe during pregnancy as long as you keep sessions to 20 minutes or less and use the lowest temperature setting that still provides relief. The concern with heat during pregnancy is raising your core body temperature, but a heating pad on a localized area at a low setting doesn’t pose that risk. A warm (not hot) bath works similarly for broader muscle relaxation.
Maternity Support Belts
Maternity belts wrap around your lower abdomen and back to redistribute the weight of your belly. In studies of pregnant women using support belts, 48% reported a decrease in pain and 63% reported feeling more supported. Women with pelvic pain rated nonrigid, flexible belts as the most effective and comfortable (82% preferred them over rigid options, which tended to ride up and dig in while sitting).
Most women in these studies wore support belts about four days a week for roughly two and a half hours per day, typically during walking, daily activities, or outings. There’s no established minimum or maximum number of hours you need to wear one. A belt won’t strengthen your core or fix the underlying cause, but it can provide meaningful relief during the activities that aggravate your pain most.
Prenatal Massage
Prenatal massage can reduce back pain, leg pain, and anxiety. For safety in the third trimester, a few guidelines apply. Massage should be performed while you’re lying on your side (with a pillow between your legs and behind your back) or sitting up. Lying flat on your back for extended periods can compress a major blood vessel and cause dizziness, and lying on your stomach is uncomfortable and potentially harmful. Deep tissue massage should be avoided, particularly on the legs, because pregnancy increases the risk of blood clots. Gentle, superficial pressure is the standard. The abdomen should not be massaged during pregnancy. Highly concentrated essential oils should also be skipped, as some are suspected of triggering contractions.
Look for a massage therapist specifically trained in prenatal work. They’ll know how to position you safely and which areas to focus on for lumbar relief.
Daily Habits That Help
Good posture sounds basic, but it’s one of the most effective interventions when relaxin is loosening everything up. Stand with your shoulders back and your weight distributed evenly rather than leaning backward to counterbalance your belly. When you breathe deeply, let your ribcage expand rather than just pushing your belly out. This engages the deep stabilizing muscles around your spine.
Avoid lifting heavy objects when possible, and when you do lift, bend at the knees rather than the waist. Wearing low-heeled shoes with good arch support helps maintain spinal alignment. If you sit for long periods, place a small pillow or rolled towel behind your lower back and take breaks to stand and move every 30 minutes or so.
When Back Pain Signals Something Else
Most third-trimester back pain is musculoskeletal and harmless, but certain patterns can indicate preterm labor. A low, dull backache below the waistline that comes and goes rhythmically (rather than staying constant or shifting with position changes) is one of the warning signs. Other signs to watch for include menstrual-like cramping in the lower abdomen, pelvic pressure that feels like the baby is pushing down, abdominal cramping with diarrhea, or any spotting or fluid leaking from the vagina.
The key threshold: if you’re having six or more uterine contractions (a tightening across your belly) in one hour, or if you experience any combination of these symptoms for an hour, contact your provider or go to the hospital. Normal back pain from pregnancy tends to be position-dependent, meaning it shifts or improves when you change how you’re sitting or lying. Preterm labor pain follows a rhythmic pattern regardless of position.