Background: Pregnancy, type of delivery, pelvic floor conditions and number of births can influence the muscle strength of the pelvic floor, causing morbidities of the genitourinary tract and negative effects related to sexual, physical, psychological and social health in women. However, few studies deal with the training of the pelvic floor muscles (PFM) during pregnancy, or in preparation for vaginal delivery. Aims: to discuss the importance of pelvic floor muscle training in childbirth preparation. Method: systematic review in SCIELO, MEDLINE, BIREME, Cochrane, Expanded Academic Index, Clinical Evidence and Pubmed databases using the keywords pregnancy and pelvic floor exercise, restricted to studies in Portuguese or English about pregnant women. Results: Of the 44 articles included, only eight dealt directly with PFM strengthening during pregnancy. Conclusion: Pelvic floor muscle exercises during pregnancy are safe and have no side effects or potential risks for pregnant women, in addition to promoting effective strengthening and increased tissue elasticity, variables capable of facilitating vaginal delivery and minimizing the risk of injuries locations and consequent impairments of pelvic, urinary, anorectal and/or sexual or pelvic statics.