The thing that still strikes me is this.
She was going to get caught at some point, it was inevitable. More inevitable than almost all serial killers because her crimes were always in the same place and the same victims in high frequency. She surely must have known she would almost definitely be caught.
She would have known perhaps if she stopped at Baby D, Baby E or even Baby F then perhaps it would have been seen as just a horrible run of bad luck. Perhaps if she had really spaced them out, maybe one every 18 months or so probably no one would have noticed and she could have probably carried on for the rest of her life. She wasn't stupid. She was clearly manipulative and was always laying the groundwork for the next kill.
With all that in mind I find it hard to get my head around how the sheer fear of being caught could be overridden by whatever it was that drove her. Overrode her choice to stop, overrode her choice to really space them out to avoid suspicion. She couldn't help herself. That's how dangerous she was.