Many women who practice this in the US will pay someone to prepare these meals for them a week at a time (they will come to your home and basically do meal prep for the week with the last few days worth going in to the freezer). There is a company in SoCal [1] that will prepare the meals and ship them to you frozen, I believe, as well.
I don't know if they're actually healthy or not but you'd hope they would be better than processed foods.
And I guess my point is that money can buy you just about anything. If you want healthy, frozen, ready-to-eat meals, they can be had for a price.
[0]: https://en.wikipedia.org/wiki/Postpartum_confinement#China
We stocked the freezer by cooking a lot before our baby was born... and then in a sleep-deprived haze I left the freezer open.
Of course, it's still better (and cheaper) to make it yourself. But in a pinch it's nothing to shake a stick at.