The bottom line is that the bible tells us very little about the first 30 years of Jesus’ life, or Mary’s either. We don’t even know when St. Joseph died—we just assume he had to have before Jesus began His ministry as St. Joseph isn’t mentioned after–but we are really not told even this. The bible doesn’t tell us that Mary was assumed into heaven and crowned queen either, just for instance. We believe these things based on tradition and the declaration of popes speaking in their role of authority and infallability. I’ve always wished that the authors of the NT had included more about Jesus’ early years–but they didn’t and this must have been God’s plan–so I accept it. But it means that we must use common sense sometimes when we don’t have absolute answers!
This does not mean that these things are fairy tales–but when you take a quote such as the one were Mary goes to visit and care for her cousin Elizabeth who was elderly and pregnant and stayed for 3 months before going home, I think it’s silly to try and draw any absolute conclusions from the quote. Personally, Mary could have gone alone. We know that Elizabeth lived in the hill country of Judea–but we don’t know how far from Mary’s home she lived or how dangerous the area was. Then again, she could have joined a caravan going in that direction. One thing I personally ABSOLUTELY believe is that if Elizabeth was far enough along in her pregnancy that St. John “leapt in her womb” when Mary arrived, then she had to be at least 20+ weeks along when Mary arrived and if Mary stayed with her cousin for 3 months, I am almost positive that she stayed to help with the birth. Whether helping with the delivery made Mary temporarily"Clean" or “unclean”, to me is pointless. I think Mary went because then–just as today–if a woman in her 60’s or above got pregnant somehow–it would be a difiicult and risky deal and Elizabeth would undoubtedly have welcomed all the help she could get. They didn’t have epidurals or C-sections back then. I just personally cannot see Mary going to Elizabeth for 3 months and going home a week before the delivery–not knowing how it turned out. Because, I’m pretty sure that even back then, Mary and everyone else would have known that an old lady having a baby was a dangerous situation. I think this is another proof of Mary’s humility and obedience. I’m fairly sure as a nurse practitioner, that Elizabeth,in the last trimester of her pregnancy, needed help with even basic household chores like cooking or laundry. Then, when she went into labor, I’d bet that any woman who lived close enough to know what was going on, would have showed up to assist as women did back then–and I cannot see Mary going home just as Elizabeth’s due date approached and leaving Elizabeth to fare on her own after already choosing to go to her to help. It’s just common sense.