I had a VERY vivid one of being pregnant & about to give birth, the birth pains were horrible! I woke up & saw I was on by back & my 10 lb cat was sitting on my stomach, so for me it was pretty obvious.
But it could also mean that you're creatively ready to make something new, or that you're thinking subconsciously about motherhood, or even it's as simple as maybe you saw something about it on the news or a show just before you went to sleep, the last things the mind takes in are often rehashed in dream state (just mind garbage in a way), as a way for the brain to deal with the events of the day.
If you dream about it several times this week, take a look at what your subconscious is trying to tell you. It's probably working on something pretty big.