Recent evidence regarding pelvic floor muscles during pregnancy

A recent study used EMG to evaluate the pelvic floor muscles (PFM) in pregnant and non-pregnant women.1 The authors found that electrical activity during PFM contraction is reduced during pregnancy. Another factor that could influence PFM electrical activity and strength could be the excessive distension of the abdominal muscles, which work most effectively in their shortened range. As the PF and abdominal muscles co-contract, weaker, distended abdominals could influence PFM strength.

The study data lets the authors ‘point out impairment in PFM function in pregnant women when compared with nulliparous women. Physiotherapists professionally trained in biomechanics and kinesiology should create exercise programs that aim to strengthen the PF during pregnancy to prevent damage to or rehabilitate the muscles. This approach would prevent PF dysfunctions that are often considered to be transitory and physiological from persisting long term, not just in pregnancy, and severely affecting a woman’s quality of life.’

They believe ‘that this decrease in PFM strength in pregnant women happens because the connective tissue undergoes intense remodeling induced by hormonal action, which is meant to facilitate dilation near the end of pregnancy. The result of remodeling is a looser vaginal region, which can cause PF dysfunction. Additionally as a result of chronic tension, the gradually stretched and weakened endopelvic fascia can trigger muscular PF dysfunction. Collagen dispersion which is provoked by alterations to conjunctive tissues from postural alterations and weight gains, can also lead to PFM weakness during the gestational period’.

Conclusions from another recent trial of pelvic floor muscle training during pregnancy show ‘that pregnant women should exercise, and in particular do pelvic floor muscle training (PFMT), to prevent and treat urinary incontinence in late pregnancy. Thorough instruction is important, and specific pelvic floor muscle exercises should be included in exercise classes for pregnant women. The preventive effect of PFMT on anal incontinence should be explored in future trials’.2


1. Electromyographic evaluation of pelvic floor muscles in pregnant and nonpregnant women. Resende A, Petricelli C, Bernardes B, Alexandre S, Nakamura M, Zanetti M. Int Urogynecol J (2012) 23:1041-1045

2. Does regular exercise including pelvic floor muscle training prevent urinary and anal incontinence during pregnancy? A randomised controlled trial. Stafne SN, Salvesen , Romundstad PR, Torjusen IH, Mørkved S.BJOG.2012 Sep;119(10):1270-80. doi: 10.1111/j.1471-0528.2012.03426.x. Epub 2012 Jul 17.