Final answer:
A woman may become pregnant while using a diaphragm due to incorrect use, failure to apply spermicide, improper fit, or not leaving it in place long enough after intercourse. Diaphragms have a typical failure rate of about 12 percent.
Step-by-step explanation:
Rationale for Pregnancy Despite Diaphragm Use
The rationale for a woman becoming pregnant while using a diaphragm as a contraceptive can be attributed to several factors. Diaphragms act as a barrier method by covering the cervix to prevent sperm from entering. However, the effectiveness of a diaphragm can be compromised if it is not used correctly. Critical steps include applying spermicide before insertion, ensuring proper fit over the cervix, and leaving it in place for at least six hours after intercourse. With typical use, diaphragms have a failure rate of about 12 percent. Additionally, diaphragms do not prevent the transmission of STIs and may increase the frequency of urinary tract infections.
Among the reasons for diaphragm failure, improper positioning, not using spermicide, or not leaving the diaphragm in place for the recommended duration can significantly decrease its contraceptive efficacy. Other barriers to effectiveness may include issues with the fit of the diaphragm or physical alterations such as weight fluctuations or childbirth, which necessitate re-fitting. Even when used correctly, no contraceptive method is entirely foolproof, and the diaphragm is no exception.