Baby dust is a term used to covey good luck to an individual who is trying to conceive a child. It is a term that can be found on infertility and trying to conceive message boards and discussion groups that often attempts to communicate understanding and a desire that there could be something more profound to say or offer someone who is hurting.
FertilitySmarts explains Baby Dust
Within the trying to conceive and infertility communities, there are mixed feelings on the use of slang terms, in general, to describe what is often a medical issue.
To some, the term is a genuine expression of positive thoughts from someone who has a bit of an understanding of what the other individual may be going through. It is a way to convey a sense of community and perhaps even the hope that there could be something 'magical' that could help resolve the situation.
To others, the idea of the cutesy term is not appealing and even hinting at the idea of 'magic' is belittling and childish; simply saying "good luck" coveys the sentiment adequately.
Groups will often communicate in an introduction or posted rules if they prefer for contributors to avoid the use of slang terms.