The Negatives of The Rhythm Method
The method offers no protection against any form of sexually transmitted infection. It requires detailed planning yet offers limited reliability. When taking temperatures, the reading can be wildly altered by cold or infection. Mucus analysis can be disrupted by the presence of other sexual discharge within the vagina. Both the temperature and mucus methods are unable to clearly identify the initial phase of the month prior the fertile phase. It can not always be accurate, as for many women ovulation does not occur on the same day every month. Sperm can survive longer than three days, which would mean sex would have to be avoided at least a week prior to ovulation to avoid risking pregnancy. The method has an 80% level of effectiveness which is much lower than all the other forms of contraception using devices, pills or surgery.