Whether you have delivered vaginally or by C-section, your pelvic floor needs time to recover from nine months of strain. Remember the vaginal canal is a muscular tube that can hold your menstrual cup in place. Too tight or too loose of a vaginal muscle can cause discomfort, movement of the cup or leaking. None of these are ideal. Additionally, your cervix may have dropped slightly or titled, both of which may mean inserting the cup or angling the cup differently for maximum cup comfort.
Your body will adjust, but it can take several months or even up to a year to find success with a menstrual cup after pregnancy.