When my wife was pregnant, she was the most beautiful female on earth! And, I think that all future fathers feel the same way. After all, that bulge is due to their love for each other and it will be another to love soon. A wonderful thing, reproducing is! I think most pregnant women look healthier and glow during those months and it's a wonderful thing to watch.
I never found that my wife was unattractive at all, but beautiful, and we had wonderful and satisfying sex up until 1 day before she gave birth. If anything, her pregnancy was a real turn on during those months.
However, that said, pregnancy is a very personal thing between a husband and wife, so I really don't find "other" women very attractive during the last few months of pregancy. I don't like to see a huge belly covered over by a stretched tee shirt and with the top of the pants pushed down under the belly inorder to make the belly show even more. It, to me, just is'nt very attractive or appealing hanging out like that.
Some decades ago, maternity clothes were designed to make the woman look as beautiful and as attractive as possible during this time. She showed and it was very obvious that she was pregnant, but it was presented in a soft, lady or motherly like way. I wish that this trend would return.
But, then, I'm a bit old fashioned in a lot of ways.