What does it mean to dream about a baby under your bed?

The baby represents some aspect of the dreamer's own personality that is hidden. It might be some immaturity that the dreamer urgently wants to conceal. Alternatively, it may be that some part of the dreamer's life is unable to mature BECAUSE it is hidden. Another possibility is that the baby represents an idea, project or task that is precious and important to the dreamer, yet needs to be hidden for some reason.