Are you referring to the one on the left behind the tree? If so, then yes, I did it, and at the end you find a fairy who sells you a fertility potion. What I don't know is how to get to the final stage of pregnancy size.
Viewing post in Livia's Pregnancy Debt jam comments
Look for a pulsing circle in the middle of the cemetery. I always did every quest as soon as I could so I'm not sure if they can be overwritten if you wait to long. Also I was in a relatively early stage of pregnancy when I went to do it, and there are a few quests that need you to be empty so that might need to be tested to see if this is the one specific quest that needs you to be pregnant during it.