In the same time period, a 'white swelling' meant she had a bun in the oven.

"Blue Bells of Ireland"

And the blue bells of Ireland
Rings well and rings well;
And the blue bells of Ireland
Rings ding, dong, bell.
Fragment of a lyric in William Chappell, Popular Music of the Olden Time, v. 2. Chappell says "I have not met with any tune under that name," but he knew about the "Joyful Maids....." (First pub. by Chappell and Co., 1859).