The combined oral contraceptive pill has a high reliability, around 99% if used perfectly and 91% with regular use.
The effectiveness of the pill can be reduced if it is not taken correctly or if it is forgotten, but also by the following factors:
- Vomiting and diarrhea within 3-4 hours after taking the pill.
- St. John's wort.
- Certain medications.
For this reason, when taking the contraceptive pill, it is advisable to inform the specialist when taking any medication or herb, in case they reduce its effectiveness.