No. While Ovatel can help determine when you are fertile, it should never be used as birth control. No ovulation kit or BBT can do that. Sperm can live up to 5 days in the female reproductive tract. Estrogen peaks approximately 24-48 hours prior to ovulation, when ferning occurs. If you have intercourse the days prior to ferning, you can get pregnant. Ovatel does not protect you against STDs – Sexually Transmitted Diseases.