Clomifene citrate or unstimulated intrauterine insemination compared with expectant management for unexplained infertility: pragmatic randomised controlled trial

The authors conclude that common treatments for infertility do not
seem to enhance fertility. This rather vague statement has been taken up
by the media as meaning that these treatments do not work. The authors’
data do not disprove their null hypothesis of no difference between
treatments. This however does not mean the null hypothesis is true i.e.
the treatments are all equally efficacious. The null hypothesis can never
be proven. If the authors were expecting little difference between
treatments they should have pre specified a non inferiority analysis.

Competing interests:
None declared