That *Unfounded speculation might have some basis in fact, but 'colonial era' times were already dangerous enough, mortality-wise. High birth-rates matched (or, indeed, exceeded) high infant-mortality rates with fewer reliable methods of contraception or countering disease and injury.
There always seemed to be enough children becoming young men to sign-up as cannon-/pike-/musket-fodder whenever needed, or hands of any gender till the fields, thread the looms, fuse the shells, etc. With quite prominent exceptions of post-Plague years and equivalent "They're all dead Dave, everybody's dead Dave, everybody's dead..." catastrophes.
Had a child been truly unwanted (or was less than healthy-looking, and a difficult decision might be made) I'm sure there was plenty of scope for nudging the child over into "unfortunately did not survive" territory, to join those that genuinely could not be saved. Once as old as a few months or a year or so, I wouldn't be so quick to suggest that a "fifth trimester abortion" had occured. Standard child neglect or 'carelessness' with the life of an awkward child that might or might not be a valid basis of a (now?) loveless marriage, maybe. (They may not know about genes, but a 'father' might well be enraged once the infant's hair starts to be obviously as red as the handsome cow-herd's...)
I dare say matters could always 'be arranged' for unexpected pregnancies, in all types and levels of society. Young ladies of high standing going to stay with maiden aunts for a few months, or otherwise quietly withdrawn from society, if the right (or willingly substitutive) dashing young officer couldn't be encouraged to step up or whatever. In a poorer rural context, there'd be traditions of working things out any which way that might be just as subtle or tacitly ignored by all the neighbours who had at some point had prior experience of what surely happens fairly most years, once spring has sprung and the young have fun...
Ok, but that's not very AmeriPolly. Not exclusively and topically so, anyway. But it seems there's not much to be said about Trump not conceding that hasn't already been said, and everything else seems to be just as stalemated. Until someone pulls something out of a hat to resolve/ignite the situation in a definite manner.