What relaxin actually does — and why six weeks is too early to be done
Relaxin is a hormone produced primarily by the corpus luteum during pregnancy and, in much smaller amounts, year-round in non-pregnant adults. During pregnancy, its levels rise sharply in the first trimester, peak around weeks 10 to 14, and remain elevated through term. Its job is to loosen the ligaments of the pelvis — the pubic symphysis, the sacroiliac joints, and the surrounding soft tissue — to allow the bony pelvis to open during delivery.
The hormone does not switch off the moment the placenta delivers. Levels drop substantially within 48 hours of birth, but measurable elevation persists for approximately three to six months, and stays meaningfully higher in breastfeeding parents for as long as breastfeeding continues. The mechanism is well-established in the obstetric and rheumatology literature: the receptor activity is systemic, not localized to the pelvis, which is why postpartum joint laxity shows up in wrists, knees, ankles, and the lower back, not only in the birth canal.
The clinical implication, which most six-week check-ups do not address directly: the body is still mechanically more vulnerable to joint strain at six weeks postpartum than it will be at six months. The repetitive lifting, the awkward feeding positions, the carrying-the-car-seat-on-one-arm reality of new-parent life all load joints that are still ligamentously loose. The Wermom team's editorial review at wermom.com/research covers the relaxin pharmacokinetics studies and the ACOG-aligned recovery timelines in full.
The four joint pains most six-week postpartum women report
The pattern is consistent enough across recovery clinics that pelvic floor PTs treat these four together as the postpartum musculoskeletal cluster. Each has a different anatomical target but a single shared mechanism — relaxin-related ligamentous laxity loaded by infant care tasks.
De Quervain's tenosynovitis, or "mommy wrist." Pain along the thumb-side of the wrist that flares when scooping up the baby, pumping, or unscrewing bottle caps. The tendon sheath at the base of the thumb becomes inflamed from the repetitive abduction-extension motion of newborn lifting. Affects roughly 30 to 50% of new mothers in the first three months by some clinic data. Resolution is typically 4 to 6 weeks once the loading pattern is modified and the tendon is rested with a thumb-spica splint, or longer if the loading continues unmodified.
Pelvic girdle pain (PGP). A diffuse, often shifting pain in the front of the pelvis, the back of the pelvis, or both, that flares with single-leg loading — getting in and out of a car, climbing stairs, rolling over in bed. The underlying anatomy is the sacroiliac joints and the pubic symphysis, both of which were ligamentously stretched during pregnancy and delivery. Most cases that began in pregnancy resolve within three months postpartum; about 20% persist beyond six months and benefit from targeted pelvic-floor and core retraining.
Sacroiliac (SI) joint dysfunction. A focal pain in the dimples at the base of the spine, often one-sided, that worsens with prolonged standing or carrying the baby on one hip. Distinct from generalized PGP because the pain is anatomically localized. Responds well to manual therapy plus glute and deep-core activation work — almost never resolves spontaneously without targeted intervention if it is still present at six weeks.
Pubic symphysis pain. A sharp pain at the front of the pelvis, between the pubic bones, that flares with separating the legs — stepping into pants, getting out of a low car, opening the legs to roll. In severe cases (a true symphysis pubis dysfunction), the gap between the two pubic bones is wider than the 4–5 mm of normal pregnancy widening. Most cases resolve within three months; severe cases benefit from a pelvic support belt and pelvic-floor PT.
The pelvic floor is the joint pain nobody names as joint pain
The pelvic floor is functionally a muscular sling that runs from the pubic bone to the tailbone and supports the bladder, uterus, and rectum. After pregnancy and birth — vaginal or cesarean — the pelvic floor muscles have been stretched, weakened, and in many cases injured in ways that the six-week obstetric check is not equipped to assess. The standard postpartum visit checks for healing of the perineal repair and the cervix, asks about bleeding and mood, and clears the patient for "exercise as tolerated" without ever assessing the muscle that determines whether exercise is actually tolerated.
The international consensus on postpartum rehabilitation — codified in the 2017 French national protocol and increasingly adopted in U.S. clinical guidelines — recommends pelvic floor physical therapy for every postpartum patient, not only those with symptoms. The reason is that the symptoms most associated with pelvic floor dysfunction (urinary leakage with sneezing or running, the sensation of heaviness in the pelvis, painful intercourse, lower back pain that does not resolve) are common enough postpartum that nearly half of women experience at least one — and most are treatable with eight to twelve sessions of targeted PT.
The Wermom team's analysis of the NIH NICHD's pelvic floor disorder research walks through the prevalence data and the underdiagnosis pattern — most U.S. women are referred to pelvic floor PT only after symptoms have persisted for months or years, when the same intervention at six to twelve weeks would have produced a cleaner recovery. Wermom's week-by-week postpartum recovery timeline walks through the broader recovery context this pain sits inside.
The graded return that ACOG actually recommends
The "six-week clearance" framing has done postpartum recovery a disservice. The clearance is for activity to begin — not for the return to pre-pregnancy intensity. The American College of Obstetricians and Gynecologists' guidance on exercise after pregnancy describes a graded, progressive return that most women never receive in detail at the six-week visit.
The conservative version: weeks 1–6 are gentle walking, breathwork, and basic pelvic-floor activations; weeks 6–12 add low-impact strength, walking distance, and core retraining; weeks 12–20 reintroduce moderate-impact activity (cycling, swimming, light jogging) with attention to pelvic-floor symptoms; full return to running, high-impact loading, and pre-pregnancy lifting is appropriate from approximately month 5 to 6 for most uncomplicated births, and meaningfully later for cesarean recovery or pelvic-floor injury. The most-cited postnatal exercise guideline — the 2019 British Journal of Sports Medicine consensus from Goom, Donnelly, and Brockwell — recommends return to running no sooner than 12 weeks postpartum, with a pelvic-floor screen before resumption.
The reason the timeline is longer than the cultural expectation: relaxin is still elevated through this entire window, the abdominal wall is still re-knitting, and the pelvic floor still requires retraining for impact loading. Pushing impact too early is associated with prolapse, urinary incontinence, and stress fractures — none of which are inevitable, all of which are more common when the timeline is compressed.
The relief plan that actually works at six weeks
Three categories of intervention have the strongest evidence base for postpartum joint pain in the literature, and they work in concert. None of them is "rest." Pure rest at six weeks postpartum tends to deepen the deconditioning that contributes to the pain.
Load management plus posture modification. Carry the baby with both arms, switch sides often, use the carrier rather than the one-hip swing, lift from a squat rather than a forward bend. Set up the feeding station so the baby comes to the breast or bottle, not the back to the baby. These small changes remove the repetitive loading that is keeping the inflamed tissue inflamed. For "mommy wrist" specifically, a thumb-spica splint worn during high-load activities (lifting, pumping) accelerates healing meaningfully.
Targeted strengthening, gradually. Deep-core breathing and pelvic-floor activation can start in week one in most uncomplicated births. By week six, the addition of glute bridges, bird-dogs, and supported squats begins to rebuild the muscular support that takes some load off the still-loose ligaments. The Wermom team's guide to pelvic-girdle stretches covers many of the same moves used in postpartum recovery.
Pelvic-floor physical therapy. The single highest-impact intervention for persistent postpartum joint pain that involves the pelvis, the lower back, or the hips. Six to twelve sessions with a pelvic-floor-credentialed PT, ideally beginning between weeks 6 and 12, is the standard protocol in countries with established postnatal rehab systems. In the U.S., this requires a referral from the obstetric provider; most insurers cover it under physical therapy benefits if framed as treatment for a specific musculoskeletal complaint (pelvic pain, urinary incontinence, low back pain, diastasis recti).
The vitamin and lifestyle inputs that show up in the evidence
Two nutritional inputs have meaningful evidence behind them for postpartum musculoskeletal recovery. The first is vitamin D — the AAP and ACOG both note that postpartum vitamin D status correlates with both maternal bone density recovery and infant vitamin D sufficiency in breastfed babies. A serum 25-OH-D level above 30 ng/mL is the conservative target. The second is adequate protein — 1.2 to 1.5 g/kg of body weight per day during postpartum recovery, higher than the standard adult recommendation, to support tissue repair and lactation.
Sleep — the input that nobody postpartum has — is the modifier behind all of these. Sleep deprivation amplifies pain perception, slows tissue repair, and increases the inflammatory cytokines that drive joint inflammation. The relief plan that pretends sleep is fixable in this window is dishonest; the relief plan that accepts the sleep deficit and works around it (chunked rest, partner rotation, daytime stillness when the baby is held by another adult) is the one that actually compounds.
Here's how Wermom App makes this 10x simpler
The hardest part of postpartum recovery is keeping track of what's normal versus what warrants a call, while operating on five hours of broken sleep. Wermom App turns the recovery plan into a daily check-in:
- Postpartum recovery tracker — log pain location, intensity, and triggers daily; the timeline auto-flags whether you are in the normal recovery curve or trending toward the patterns that benefit from a pelvic-floor PT referral.
- Graded return-to-activity guide — ACOG-aligned weekly milestones from week 6 through week 24, with pelvic-floor screening prompts before each impact-level progression.
- Six-week+ symptom decision tree — a swipe-through that distinguishes the "still hurts, normal" pains from the symptoms that warrant a call to your provider, reviewed by our pelvic-health advisors.
The shorter answer, for the parent reading this at the kitchen counter
If you are six weeks postpartum and your wrist, hip, lower back, or pelvis still hurts, that is not a sign that something is wrong with your recovery. It is a sign that relaxin is doing what relaxin does, that the muscles need retraining the discharge folder did not mention, and that you likely belong in a pelvic-floor PT chair for six to twelve sessions. Ask your obstetric provider for the referral by name. Modify the load — both arms, smaller lifts, supported posture. Begin gentle strengthening. Protect protein and vitamin D. The body recovers; the timeline is longer than the calendar implies; the pain is signal, not failure. For the editorial mission behind the Wermom team's postpartum coverage and the advisors who shaped it, see our editorial principles.