Ogino method; rhythm method
A birth control method based on the Ogino theory of ovulation timing. Also known as the calendar-based rhythm method.
The Ogino method is a way to avoid pregnancy by predicting the ovulation day.
The basal body temperature method tracks daily temperature changes to identify ovulation, while the Ogino method relies on calendar calculations.
Named after Japanese gynecologist Kyusaku Ogino, who developed the ovulation-timing theory in the 1920s.