Effects of cesarean section and vaginal delivery on abdominal muscles and fasciae

Background and objectives: Possible disorders after delivery may interfere with the quality of life. The aim of this study was to ascertain whether abdominal muscles and fasciae differ in women depending on whether they experienced transverse cesarean section (CS) or vaginal delivery (VA) in comparison with healthy nulliparous (NU). Materials and methods: The thicknesses of abdominal muscles and fasciae were evaluated by ultrasound in 13 CS, 10 VA, and 13 NU women (we examined rectus abdominis (RA); external oblique (EO); internal oblique (IO); transversus abdominis (TrA); total abdominal muscles (TAM = EO + IO + TrA); inter-rectus distance (IRD); thickness of linea alba (TLA); rectus sheath (RS), which includes anterior fascia of RS and posterior fascia of RS (P-RS); loose connective tissue between sublayers of P-RS (LCT); abdominal perimuscular fasciae (APF), which includes anterior fascia of EO, fasciae between EO, IO, and TrA, and posterior fascia of TrA). Data on pain intensity, duration, and location were collected. Results: Compared with NU women, CS women had wider IRD (p = 0.004), thinner left RA (p = 0.020), thicker right RS (p = 0.035) and APF (left: p = 0.001; right: p = 0.001), and IO dissymmetry (p = 0.009). VA women had thinner RA (left: p = 0.008, right: p = 0.043) and left TAM (p = 0.024), mainly due to left IO (p = 0.027) and RA dissymmetry (p = 0.035). However, CS women had thicker LCT (left: p = 0.036, right: p < 0.001), APF (left: p = 0.014; right: p = 0.007), and right IO (p = 0.028) than VA women. There were significant correlations between pain duration and the affected fasciae/muscles in CS women. Conclusions: CS women showed significant alterations in both abdominal fasciae and muscle thicknesses, whereas VA women showed alterations mainly in muscles. Thinner RA and/or dissymmetric IO, wider IRD, and thicker LCT and APF after CS may cause muscle deficits and alteration of fascial gliding, which may induce scar, abdominal, low back, and/or pelvic pain.