Key Message
For the comparative clinical effectiveness of ulipristal versus levonorgestrel for use as emergency contraception, two randomized controlled trials (RCTs), were synthesized in one moderate-quality and one critically low-quality systematic reviews. One evidence-based guideline for Canadian practitioners by the Society of Obstetricians and Gynaecologists of Canada was identified. There is evidence to show that ulipristal is more effective than levonorgestrel to reduce the risk of pregnancy. The included meta-analysis found that there was no evidence to show differences in the risks of adverse effects, including nausea and vomiting between the two agents. One SR concluded that a BMI greater than or equal to 30 was associated with an increased risk of pregnancy after using levonorgestrel but not ulipristal for emergency contraception. This corresponded to the guideline that indicated ulipristal is recommended for those with a BMI equal to or greater than 25 who are seeking emergency contraception. Due to limited evidence and heterogeneity in the doses, further research addressing ulipristal versus levonorgestrel may help to reduce uncertainty.