Method™ guidelines for avoiding pregnancy for one year. There were five pregnancies in the study which were classified as people who did not listen to the information and therefore did not follow the guidelines. These were classified as Teaching Related Pregnancies. Method Related Pregnancies was 0%. As of 2005 there were close to 4 million Chinese couples using the Billings Ovulation Method™.

In Indonesia, a trial done from 1978 - 1982 involved 1331 couples during a 42 month program and concluded a method effectiveness rate of 99%.

In India, there were 2059 couples following the Billings Ovulation Method™ for 21 months. The method effectiveness was 99.15%.

For more on the effectiveness of the Billings Ovulation Method™: www.woomb.org/bom/trials/index.html.

Details on the science and methodology of the Billings Ovulation Method™ can be found on www.woombinternational.org