Putting evidence into practice.

Clinical effectiveness is defined as the extent to which specific clinical interventions, when used in the field for a particular patient or population, do what they are intended to do. The evidence base for achieving clinical effectiveness in family planning is improving mainly because fertility control is a high international public health priority. Evidence generated by methodologically sound and substantial international research programs means that family planning services can make major strides toward achieving clinical effectiveness by investing in methods already shown to work effectively and acceptably. The WHO trial of emergency contraceptive (EC) regimens published in the Lancet earlier in the year is an example. A large, well-conducted, randomized controlled trial found the progestogen-only regimen to be more effective and better tolerated than the combined estrogen-progestogen regimen. Trial results also strongly suggest that both regimens are more effective in preventing pregnancy when taken earlier in the 72-hour window after unprotected sex. Some researchers, however, are discouraging the abandonment of the combined regimen in favor of the progestogen-only approach. While it remains to be seen whether the WHO trial results will be duplicated in future research or translate directly to the UK population, it is unlikely that the study's key findings will be reversed by future research. The lack of a licensed progestogen-only EC formulation places the UK's family planning field in an unsatisfactory interim situation.