I seem to remember reading - yes, sloppy anecdote I know - that the incidence of child murder was still at a very low level historically, but the availability of news coverage increased our visibility of it markedly.
It does feel like there are a lot more of these cases in the last few years, and the vast majority of them seem to be by men who are "revenging themselves" on their partner. It seems an odd choice; I would have been far more likely to bump off XW than my kids, and I'd probably have been out of prison in 10 years. Why would child murder and suicide be in any way a rational response?
It also feels like there is a rise in child killings by women [some asylum based, some based on fears for the child, but also a bit "mine, can't have"]; I'd have though that was mostly societal impact.
Is there a causative link to some of the media hysteria whipped up by F4J etc?
"You'll never see your kids". Mostly bollocks, of course, as even with a difficult XW my access was sorted legally.