My biggest problem with the scenes was that the nurse seemed to be saying that the miscarriage was just one of those things and not due to her age. Isn't the risk of miscarriage like 50% after 40 so it must be almost inevitable at 50 with your own eggs.
I think the biggest thing for Erica is that she hasn't just lost a baby, she knows deep down that she's just lost her only chance of ever having a child. She referred to it as her last/only chance when she told Nick and was deciding whether to keep it or not. Whether you're particularly maternal or not, those thoughts must occur to you if you're childless by a certain age.