That seems obvious, but a lot of women who think they are sure, change their mind. Studies have shown that the 3-25% of women regret tubal ligation. The most common reason is a change in marital status, particularly in young women. While post-sterilization pregnancy is possible utilizing in vitro fertilization techniques, the expense is prohibitive for many and relatively few women pursue it.
While the new methods of sterilization are much safer and easier than they used to be, there are still small risks and a procedure involved.