'I think, my dear, I can make his lordship dance the dance of expectation a couple of years at least; and whilst I am mother-expectant, I hope I may be able to dispose of my daughter in an honourable manner.'
So saying, this mother-expectant withdrew in a most matronly manner to her own dressing-room.
—Robert Bage, 1796, Hermsprong
The surprising thing is that 'expectant' here is not used in the way you would usually associate with 'mother'; though Bage, in 1796, has no difficulty talking about sex and pregnancy in a way that would be impossible for Jane Austen a short few years later. Rather, the arch young lady saying this to her friend of the same age is discussing her plot to ensnare the friend's tyrannical father in order to help her: she has no intention of actually becoming his wife (and therefore her friend's mother), but wants to keep him in expectation.