Pelvic Pain During Pregnancy in the Third Trimester: Beyond “Just Hormones”
Pelvic pain in the third trimester is incredibly common.
Some studies report up to 86% of pregnant individuals experiencing some degree of discomfort in the pelvis, hips, or lower back. While hormonal changes often get the blame, especially the effects of relaxin and progesterone on joint laxity, the reality is much more nuanced.
As a pelvic floor physical therapist, I work closely with clients experiencing this pain, and I can confidently say: hormones may open the door, but biomechanics, muscle coordination, and structural stress often walk through it.
As the baby grows, the body undergoes major biomechanical changes. The shifting center of gravity and increasing weight from the uterus significantly impact posture and walking patterns.
These shifts increase the lumbar curve and anterior pelvic tilt, which can strain both the lower back and pelvic joints. Pregnant individuals often adopt new movement strategies to maintain balance and stability which may actually overload the pelvic region further.
For example, avoiding weight through one leg or waddling with a wider stance can inadvertently stress the sacroiliac joints and pubic symphysis.
Neuromuscular Changes
Equally important but less talked about are the neuromuscular changes.
The pelvic floor muscles are key players in supporting the pelvis and may become overworked or fatigued. Research has shown that muscle endurance in the pelvic floor decreases later in pregnancy, likely due to both mechanical load and neuromuscular adaptations.
To compensate, other muscles, like the hip rotators, low back extensors, or glutes, may pick up the slack. Unfortunately, this can lead to imbalances and trigger points, especially in muscles like the levator ani and obturator internus, which are frequently tender in those with pelvic girdle pain.
Structural Conditions
Pelvic pain in the third trimester can also be driven by structural conditions unique to pregnancy.
One well-known example is symphysis pubis dysfunction (SPD), where the joint at the front of the pelvis becomes hypermobile or irritated.
Similarly, stretching of the round ligaments, which support the uterus, can cause sharp, stabbing groin pain, especially during sudden movements.
In rare cases, even nerve entrapments, such as pudendal nerve irritation or sacral nerve tension, may contribute to persistent pelvic discomfort or radiating symptoms.
The abdominal wall also plays a role, particularly in cases of diastasis recti, a condition where the rectus abdominis muscles separate. As this separation widens, it reduces the body’s ability to regulate intra-abdominal pressure and stabilize the core.
This lack of support forces the pelvic floor and surrounding muscles to work even harder to maintain postural control, potentially worsening pain and fatigue.
Hormones
So where do hormones come into play?
While relaxin and estrogen do increase joint laxity to prepare the body for birth, research over the last decade shows no consistent link between hormone levels and the intensity of pelvic pain.
Not everyone with elevated relaxin experiences pain, and some with low levels still do. Hormones may set the stage, but they're far from the only actor in this complex picture.
Treatment of pelvic pain during pregnancy
From a treatment perspective, this broader understanding is empowering.
As pelvic floor physical therapists, we use targeted assessments to identify which muscles are weak, overactive, or poorly coordinated.
We evaluate posture, joint mobility, functional movements like walking or stair climbing, and core engagement patterns.
Treatment often involves pelvic floor strengthening (but only when appropriate), core stabilization, manual therapy for joint and soft tissue restrictions, and education on body mechanics. Our goal isn’t just to manage symptoms, it’s to optimize how the body moves and supports itself during a time of massive change.
Importantly, we also work in partnership with OB-GYNs, midwives, and other professionals to rule out more serious causes of pain, such as urinary tract infections, preterm labor signs, or neurologic involvement. When pain persists beyond pregnancy or becomes debilitating, a multidisciplinary approach can be essential.
At the end of the day, pelvic pain during the third trimester is a multifaceted condition that deserves more than a hormonal explanation.
While hormones like relaxin may loosen ligaments in preparation for birth, they are not the sole cause of discomfort.
Instead, this pain often arises from a complex interplay of biomechanical shifts, muscular adaptations, joint stresses, core depletion, and psychological responses to pain. By taking a whole-body approach and addressing posture, muscle coordination, movement mechanics, and emotional wellbeing, we can offer real, lasting solutions.
This nuanced understanding empowers expecting individuals and their pelvic floor therapists to target interventions effectively, helping them move through this transformative period with greater comfort, confidence, and resilience.
Looking for pelvic floor physical therapy in Jacksonville Beach, FL?
If you’re looking for personalized, one-on-one sessions to address your pelvic floor concerns, we provide pelvic floor physical therapy services to women in the Jacksonville Beach area.
If you’re looking for providers who will listen to you and help you get to the root cause of your pelvic health concerns, we’ve got you. We’re here to help you if you’re experiencing pelvic pain, pelvic heaviness, leaking, or are pregnant/postpartum and want to continue safely working out/running/lifting during your pregnancy and get back to your sport after birth.
Get started today by booking a discovery call.
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