A weak pelvic floor can cause a variety of complications.
Most common, is loss of bladder control. There are different strains of urinary incontinence that a weak pelvic floor muscles can cause. Leaking when coughing or sneezing for example is known as stress urinary incontinence. Having a sudden need to use the toilet which often results in leakage is known is urge urinary incontinence. You can also have a mix of the two which is called mixed Urinary Incontinence.
A weak pelvic floor can also cause sexual difficulties such as reduced vaginal sensation and lower back pain due to poor posture and slumping.
In more severe cases, there is also a risk of prolapse which is when the internal organs that are usually supported by the pelvic floor including the bladder and uterus can slide down into the vagina.