Don't know this lady's story. But post natal psychosis is a real tragic thing that can happen. This isnt the action of someone possessing their faculties.
Why when abortion is available would you carry to term -and then so impulsively act? If for whatever reason she didn't want the baby and couldn't get the abortion, she had months to come up with a better plan than 'throw it out a window'. Either she was undiagnosed with something the whole time, or the birth triggered a psychological episode imo.
Pregnancy and birth normally is traumatic and fucks you up. Your brain is doing wild things chemically and drowning in hormones, that sometimes actually push people into a temporary insanity. People with postpartum psychosis can become violent to themselves and others, hallucinate, have delusions, etc. It happens ~2 out of 1,000 births. And is more likely if the person had an untreated mental health problem beforehand. Getting angry that somebody cut you off is not a medical thing. Psychosis 10 minutes after labor usually is.