How effective is the diaphragm as a contraceptive method?
If used perfectly the probability of failure during the first year of use for the diaphragm is 4 -8%. While consistent and correct use of these products is essential for effectiveness, approximately one-half of the failures in diaphragm users occur despite diligent use. The Pearl index is 4-20/100 women years (failure rate for 100 women using the method for one year). The lower failure rates occur in older women probably because they have lower natural fertility with advancing age.
