I listened to her interview this morning. I found it incredibly obvious that she is not working with a full deck. That being said...
Here's my theory:
She said that each time she used IVF to conceive her first six kids. She stated that they transferred 6 "every time", so this time was no different. She wanted to try for "one more girl" so they transferred another six (because her history showed that it worked for her) and for some reason, all six took and some divided (she does have a set of twins already at home).
Maybe they tweaked her meds to make sure that she would be able to conceive and that made her body accept all six.
I'm not condoning what she did, but this is a plausible outcome.