Hip Pain During Pregnancy: What's Actually Causing It

If your hips have started aching sometime around the second trimester, you've probably already heard the explanation: it's relaxin, the hormone that loosens your ligaments to get your body ready for birth. I told clients the same thing for years. The trouble is, when researchers went looking for an actual link between relaxin levels and pregnancy hip or pelvic pain, they mostly didn't find one. That doesn't mean the pain isn't real, and it doesn't mean Pilates can't help - it means the honest explanation is more useful than the relaxin story, and it points toward exercises that actually address the problem instead of ones that just feel cautious.

Why Relaxin Isn't the Whole Story

Relaxin does rise early in pregnancy and does soften the ligaments around your pelvis - that part is accurate. What's shakier is the next step people usually take, which is assuming that looser ligaments are what's causing your hip to ache. A systematic review by Aldabe and colleagues looked at six studies on relaxin and pelvic girdle pain. Only two found any link, and both were low quality. The other four found no connection at all, and three of those were high-quality studies. If relaxin alone caused the pain, you'd expect a much clearer pattern than that.

So the hormone is real, the laxity is real, but "your ligaments are loose, that's why it hurts" turns out to be a tidier story than the evidence actually supports.

What's Actually Driving the Pain

The more accurate picture is multifactorial, closer to how we now understand most persistent pain. A scoping review by Daneau and colleagues points to progesterone, not relaxin, as the hormone more likely tangled up in pregnancy-related pain. On top of that, the APTA's clinical practice guidelines (Clinton et al., 2017) list the real risk factors: a history of low back or pelvic pain, prior pregnancies, asymmetric ligament laxity, a higher BMI, smoking, and even job dissatisfaction or not believing the pain will improve - which sounds unrelated to your hip joint, but pain is like that.

Then there's simple mechanics. As your belly grows, your center of gravity shifts forward, which changes how load travels through your hips, pelvis, and low back all day. If the muscles around your hips can't quite keep up with that new demand - which is extremely normal, not a personal failing - the joint and surrounding tissue end up carrying more than they're used to. Everyday contributors like long stretches of sitting, which tightens the hip flexors, or sleeping on one side without support, can tip things further. None of this is a flaw in your body; it's just a lot of new demand arriving faster than your muscles can adapt to it.

Where Pilates Can Help

Pilates isn't going to change your hormone levels or tighten a ligament back up, and I'd be doing you a disservice if I implied otherwise. What it can do is help the muscles around your hips, pelvis, and trunk share the load better, which is exactly the mismatch the research points to. That's strength and control work, not stretching your way out of it.

Think of it as motor control rather than flexibility: your glutes, deep hip rotators, and the muscles that stabilize your pelvis need to learn to fire well before a joint that's a little looser starts to ache under everyday demands like walking, climbing stairs, or getting out of a car. Pilates is built around exactly that kind of precise, low-load, high-repetition work, which is part of why it shows up so often in prenatal physical therapy recommendations even though the research on relaxin itself is thin.

I tell clients: we're not trying to out-stretch the hormones. We're trying to give your hips a stronger, steadier base to work from while your body is doing something enormous.

Aviva Reinhart

This is also why a generic "pregnancy-safe" class isn't always enough - you want movement that specifically builds hip and glute control, done at a pace your changing balance and joint position sense can actually handle.

Safe Moves to Try

• Clamshells, side-lying: Knees bent, feet stacked, lift the top knee without rocking your pelvis back. Builds the outer hip muscles that stabilize the joint.
• Side-lying leg lifts: Straight top leg, lifted to hip height, control on the way down. Add a light band around the ankles once this feels easy.
• Standing hip hinge with support: One hand on a chair or wall, hinge at the hips with a flat back, feeling the work in your glutes and hamstrings rather than your low back.
• Modified bridging: Feet hip-width, press through the heels to lift the hips a comfortable amount - not a full high bridge - and lower with control. Many instructors switch this to an incline or all-fours version later in pregnancy; ask yours which fits your stage.
• Seated hip circles: Small, controlled circles each direction to keep the joint moving through a comfortable range without loading it.

Keep everything in a pain-free range, and expect to modify the same exercise differently from one trimester to the next - that's normal, not a sign you're doing it wrong.

Movements to Skip for Now

• Deep, asymmetric lunges or splits that load one hip much harder than the other.
• Forced wide turnout or very wide second-position stances, which can stress the front of the hip and the SI joints.
• Long static holds at the end range of a hip stretch - a little tension is fine, but pushing into a deep, sustained stretch can aggravate an already-irritated joint.
• Flat on your back for extended periods later in pregnancy, for reasons that apply well beyond your hips - see our piece on why Pilates classes avoid this position.

Honest Verdict: Where to Start

Hip pain in pregnancy is common - roughly half of pregnant women have some low back or pelvic pain at some point, so you're not an outlier and you haven't done anything wrong. It's also not a sign that your ligaments are failing you; it's much more likely a sign that your hips are being asked to do more than they're used to, with less warning than you'd like. Targeted strength and control work, done at a sensible pace, tends to help more than rest alone.

If you're new to prenatal Pilates, start with a qualified instructor who will scale these moves to your trimester rather than handing you a generic pregnancy playlist, and loop in your OB, midwife, or a pelvic health physical therapist if the pain is sharp, one-sided and worsening, or comes with swelling, fever, or trouble bearing weight - that combination is worth getting checked rather than worked around.

Frequently asked

Does relaxin actually cause hip pain during pregnancy?

Not on its own, as far as the research shows. A systematic review of six studies found only two weak, low-quality links between relaxin levels and pelvic pain, while four studies - three of them high quality - found no link at all. The more likely explanation is a mix of shifting load, muscle strength, and other risk factors rather than the hormone itself.

When should I see a doctor about hip pain in pregnancy?

Check in with your OB, midwife, or a pelvic health physical therapist if the pain is sharp, one-sided, and getting worse, or if it comes with swelling, fever, or trouble bearing weight on that side. Ordinary aching that eases with rest and gentle movement is common and usually not a red flag, but it's always fine to ask.

Can Pilates make pregnancy hip pain worse?

It can, if you push into deep stretches, hold asymmetric positions, or ignore pain as a stop signal, so working with a qualified prenatal instructor matters. Done at the right intensity and range for your trimester, Pilates is far more likely to help than hurt.

Will pregnancy hip pain go away after I give birth?

For most people it improves considerably once the pregnancy-specific load and hormonal shifts resolve, though it can take weeks to months rather than days. If hip or pelvic pain persists well into the postpartum period, it's worth a follow-up with a pelvic health physical therapist rather than assuming it will simply fade.