In other countries, such as Morocco, it is done for any special occasion. It is done during the seventh month of pregnancy, after having the baby, weddings, engagements, family get-togethers, as well as many other reasons to simply celebrate an event.
Mehndi decorations or rather "henna tattoos" became fashionable in the West in the late 1990s. This term is not accurate, because tattoos are defined as permanent surgical insertion of pigments underneath the skin, as opposed to pigments resting on the surface.