My normal ring size is a 4.5. I'm 8 months pregnant right now and I can still wear my engagement ring and wedding band, though they are very tight. They measure about 4mm together. I would like to stack a third ring, which is a David Yurman twist band measuring about 2.5mm. How much should I size up? I was thinking of having all three rings sized to a 4.75 or a 5. Which would be better?