Percentage of pregnancies prevented (IMAGE) The University of Hong Kong Caption Study shows that the percentage of pregnancies prevented by piroxicam-levonorgestrel co-treatment was significantly higher than that of the levonorgestrel emergency contraceptive pill alone. Credit The University of Hong Kong Usage Restrictions N/A License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.