So, given the situation, there are several possible solutions that could have prevented the tragedy, but each one has thorny issues of its own.
1. Forced sterilization--In hindsight, this could be considered an excellent solution, but what American in their right mind would advocate or support such a measure?
2. Involuntary commitment to a mental facility--This solution if applied judiciously could be of great benefit, but also carries with it the potential for abuse, and violates our cherished notions of liberty.
3. Abortion--In other words kill the kids before Mrs. Yates could. Would the children have been better off? Would she still experience the hormonal changes that precipitate the psychosis? Of course, this is an approach which is in widespread use.
4. Placement of the children in foster homes--This might work. The issues with it are obvious.