For me they are never literally "dropping dreams," i.e., dreams in which I drop the baby out the window. But I like the terminology, so I'm keeping it.
I picked up that term from something or other I read during my first pregnancy — not a normal you're-having-a-baby book, it was possibly some kind of feminist or sociological theory of pregnancy or birth thing. I use the term to mean any sort of dream in pregnancy that expresses, in a fascinatingly weird and sometimes amusingly armchair-psychologist way, worries or ambivalence about the coming new member of the family. In whatever book or article I originally read, she claimed that lots of women have dreams in which they "drop" the baby, sometimes in a horrifying accident, other times as a deliberate act — out a window, from an airplane, off a cliff, whatever. A similar category are dreams in which the mother gives birth to a puppy or a kitten or some such thing.
Me, I usually have dreams of misplacing the baby. The recurring pattern — I have dreamed a variant on this dream at least once in each of my four pregnancies — is that I dream I give birth to a baby who is full-term but freakishly small. Ranging in size from, say, Polly Pocket to Barbie. And then in the dream I put the baby down somewhere, as if he were a cell phone, and then can't remember where I put him, and that's the end of that particular journey through motherhood. Usually the dream is emotionally fraught, not in grief or concern over the lost baby, but with being worried that the authorities will come and throw me in jail, and then who is going to take care of my other kids?
Psychoanalyze that. I think it's pretty obvious if you ask me.
I also have weird dreams of another category, mostly taking the form of "Labor and Childbirth: Odd Ways To Think About It." Like, for instance, dreams in which I have a pouch, sort of like a kangaroo, except it's more like a hip pocket, and just reach in and pull the baby out. Perhaps this is some kind of wishful thinking. Or perhaps it's just an extension of the cell phone metaphor. In any case, it's not very realistic, not the least because I never seem to have any useable pockets, or to use the ones I do have.
Mothers among you: Do you have "dropping dreams" or "extremely alternative childbirth" dreams? What do you think they're expressing?