Round Ligament Pain in Pregnancy: Why It Happens and What Helps

If you've felt a sudden, sharp stab low in your belly or groin sometime in pregnancy—usually on the right side, often when you stand up too fast, roll over in bed, or laugh at the wrong moment—you've probably met your round ligaments. Round ligament pain is one of the most common, and most alarming-feeling, discomforts of the second trimester, and for the vast majority of pregnant people it's exactly what it sounds like: a stretching, overworked ligament, not a sign that something is wrong with you or your baby. The short version is that gentle hip-opening stretches, some core support work, and slowing down your transitions from sitting or lying to standing tend to help more than rest alone, and a few Pilates-style moves target this specific problem better than the generic advice to "just take it easy."

What Round Ligament Pain Actually Is

The round ligaments are two thick, cord-like bands that run from the front of your uterus down through your groin, roughly along the crease where your legs meet your pelvis. Their job, even before pregnancy, is to help hold your uterus in place. As your uterus grows through the first and second trimesters, those ligaments have to stretch to keep up, and stretched tissue that's also under tension is prone to catching—WebMD describes it as connecting the front of the womb to the groin, the area where your legs attach to your pelvis, which is exactly where people usually point when they describe the pain.

Some people also feel it lower, closer to the labia, because the ligament's fibers extend that far down. That version has picked up the nickname "lightning crotch" in pregnancy forums, and it's the same structure doing the same thing, just felt in a different spot.

Why It Happens

There are really two separate mechanisms at play, and it helps to know both because they call for slightly different responses. The first is the slow, background stretch: your uterus is roughly the size of a grapefruit by 12 weeks and closer to a soccer ball by the third trimester, and the round ligaments simply have to lengthen to accommodate that, which can produce a dull, achy soreness on its own. The second is the sudden kind—a quick sneeze, cough, laugh, twist, or fast change of position can tug the ligament sharply, "like a rubber band snapping," and that's the jabbing, catch-your-breath pain most people are describing when they ask about this. It's most common in the second trimester, when the uterus is growing quickly but the ligaments haven't fully adapted yet.

"The stab makes you think something's torn. Nothing is torn—a ligament that's three or four months into a nine-month stretch is just telling you it noticed."

Aviva Reinhart

Can Movement Make It Worse?

This is where a lot of well-meaning advice goes sideways. The instinct is to move less, but the pattern that actually triggers most episodes isn't movement in general—it's sudden movement, particularly standing up quickly from sitting or lying down, or hip extension done without any transition (think: springing up off the couch). Slow, controlled movement is not the enemy here, and in fact a combined approach of stretching the hip flexor and side-body area while strengthening the abdominal wall to better support the growing uterus is the strategy that shows up consistently in prenatal exercise guidance, including from trainers who specialize in this exact complaint. The goal isn't to avoid movement; it's to change how you move in and out of positions, and to give the ligament some slack through the hip on a regular basis rather than only stretching it involuntarily when you sneeze.

Pilates-Style Moves Worth Trying

None of these are exotic. They're slow, supported, and meant to be done two or three times a week rather than pushed through in one heroic session:

• Half-kneeling hip flexor stretch with a reach overhead. Kneel on one knee (pad it well), tip your pelvis under slightly, and reach the same-side arm up and slightly over. This opens the front hip and the side body in the exact line the round ligament runs through.
• Side-lying clam or leg lift, done slowly. Lying on your side (propped on a wedge or pillows as pregnancy progresses), lift the top knee or leg with control. This builds hip and pelvic stability without any sudden hip extension.
• Modified bird dog, on hands and knees. Extend one arm and the opposite leg slowly, keeping the low back still rather than sagging or arching. This is one of the more reliable ways to build the deep core support that takes some of the job off the ligaments, and it's safe on hands and knees at any stage of pregnancy since you're not lying flat.
• Standing pelvic tilts with breath. Feet hip-width, hands on your belly, gently tilt the pelvis under on an exhale and release on an inhale. Small movement, but it teaches the transition control that prevents the sudden-tug version of this pain.
• 90/90 side stretch, seated. Sitting with both knees bent to one side, lengthen up through the opposite side body. This is a gentler, seated way to get the same lateral opening as a kneeling side stretch if kneeling isn't comfortable.

Ten minutes, three rounds through two or three of these, most days you have a spare moment, is plenty. This isn't a workout you need to build up to; it's maintenance.

What to Skip or Modify

A few adjustments are worth making regardless of how far along you are:

• Skip fast transitions. Roll to your side before sitting up, and push up with your arms rather than crunching forward. Pause before standing rather than popping up.
• Go easy on deep spinal twisting, especially loaded or fast twisting through the midline—it's a similar mechanism to the sudden-tug pain, just self-inflicted.
• After the first trimester, avoid long stretches lying flat on your back; work side-lying, seated, or propped up instead, which most of the moves above already are.
• Skip anything that asks you to brace hard and hold—long isometric ab holds increase pressure through the midsection in a way that doesn't help here. Gentle, moving core work is more useful than a hard plank hold.

And one honest caveat, because it needs saying in a piece about pregnancy pain: this article, and Pilates in general, is not a substitute for your prenatal care. If you have a high-risk pregnancy, a history of preterm labor, or your clinician has already given you activity restrictions, run any of this past them first—it takes one message to your OB or midwife and it's worth it.

It's also worth knowing what round ligament pain is not. Contact your clinician the same day if the pain is severe, lasts more than a few minutes rather than passing quickly, comes with fever or chills, hurts when you urinate, or makes it hard to walk—those aren't features of ordinary round ligament pain, and they deserve a real look rather than a stretch.

Where to Start This Week

If you're dealing with this now, I wouldn't overthink it: pick two or three of the moves above, do them for ten minutes on however many days you can manage, and pay attention to whether the sharp-catch version of the pain gets less frequent over a couple of weeks. For most people it does, though it rarely disappears completely until the ligaments finish adapting, which for some people is basically the whole pregnancy. This won't fix everything about how your body feels right now, and it's not meant to. But between slower transitions, a little hip and side-body opening, and core work that actually supports the load instead of bracing against it, most people find the stabbing version of this pain gets a lot more manageable, and a lot less scary once they know what it is.

Frequently asked

Is round ligament pain dangerous?

For most pregnant people, no. It's a normal side effect of the uterus growing and the round ligaments stretching to keep up, most common in the second trimester. It becomes a concern only if the pain is severe, lasts more than a few minutes, or comes with fever, chills, or trouble walking.

Why do I feel it more on one side?

The round ligaments run on both sides of the uterus, but it's common to notice the sharp pull more on one side than the other, most often the right. Feeling it on both sides, or switching sides, is also normal.

Can Pilates actually prevent round ligament pain?

Nothing fully prevents it, since some stretch is a normal part of pregnancy. Slow hip-opening stretches and gentle core strengthening done regularly tend to reduce how often the sharp, catching version happens.

When should I stop and call my clinician instead of stretching?

Call the same day if the pain is severe, doesn't ease after a few minutes, or comes with fever, chills, pain when urinating, or difficulty walking. Those symptoms point to something other than ordinary round ligament pain.