My understanding is that the artificial insemination was from the womans own eggs, inseminated in vitro from a single male donor.
There are those who, usually for religious reasons, object to in vitro insemination since usually many embryos are produced, and the majority are "culled" as unsuitable/defective. Murder #1?.
The first few inseminations were with one or two embryos, and produced her first children one or two at a time. All her children apparently were from implanting of embryos from the single fertilization, with the remainder being kept "in storage" for possible later use.
There are many who, usually for religious reasons, object to any use of "left over" embryos, as for stem cell research, on the grounds that such use "kills a baby." (Of course an embryo not used dies just as certainly, but that's a separate argument?) Murder #2?
The woman was reaching the age at which further pregnancies would have lesser chance of success, and was facing the "left over embryo" problem - what to do with them.
Perhaps when they asked "how many do you wnat before we toss the left-overs" she just said "all of them" - for reasons that I don't find particularly humane or morally defensible but that might have made sense in what she thinks is a rational(?) mind.
I find it difficult to believe that there was no "co-enabler" in her madness unconventional choices.