Are transversus abdominis/oblique internal and pelvic floor muscles coactivated during pregnancy and postpartum?

Aim The aim of this study was to simultaneously evaluate both transversus abdominis/internal oblique (Tra/IO) and pelvic floor muscles (PFM) during isometric exercises in nulliparous, pregnant, and postpartum women. Methods The study included 81 women divided into four groups: (G1) nulliparous women without urinary symptoms (n=20); (G2) primigravid pregnant women with gestational age 24 weeks (n=25); (G3) primiparous postpartum women after vaginal delivery with right mediolateral episiotomy (n=19); (G4) primiparous postpartum women after cesarean section delivery, with 40 to 60 days of postpartum (n=17). The assessment consisted of simultaneous surface electromyography (EMGs) of the PFM and Tra/IO, during three isometric maximum voluntary contractions. Results Only nulliparous women presented significant simultaneous Tra/IO and PFM co-activation when asked to contract PFM (P=0.0007) or Tra/IO (P=0.00001). Conclusions There is co-activation of the transversus abdominis/internal oblique and the pelvic floor muscles in young, asymptomatic nulliparous women. This pattern was modified in primigravid pregnant and primiparous postpartum women regardless of the delivery mode. Neurourol. Urodynam. 32: 416-419, 2013. (c) 2012 Wiley Periodicals, Inc.