As I'm sure many people here know, Julia was Julius Caesar's daughter and Pompey the Great's (4th IIRC) wife (the two seemed to actually be in love despite the marriage being political). She died in premature childbirth in 54 BC after seeing her husband's toga covered in blood and assumed it was Pompey's, although it was blood from rioters in the forum not Pompey's, and went into early labor. She died and her son died soon after.
So, what if Julia doesn't go into labor that day, and gives birth to a healthy son later on. How much, if any, would this affect the coming civil war? Do Pompey's personal ties to Caesar change his decisions at all?