How can I help my pregnant wife with her panic attacks and anxiety she reads into everything online and believes the worst case situation and thinks she is going to die or go crazy every time she has a panic attack and she has 3-4 a day

Having . Having three to four panic attacks per day is a high frequency. If is not uncommon for someone experiencing a pain attack to believe that they are going crazy or that they are going to die. Panic attacks do not kill people, but with that said, she must be feeling miserable. Please encourage her to see a psychiatrist and / or a clinical psychologist. There are helpful treatments that do not involve use of psychiatric medications such as cognitive behavioral therapy, deep breathing exercises and progressive muscle relaxation. However, with the described frequency and intensity of her panic attacks, she may need to consider taking medication. It is always the woman's choice if she elects to take medication and it should be discussed with both her obstetrician and her psychiatrist.
CBT. I would suggest finding a cognitive behavioral therapy specialist from your local psychological association to assist in cognitive restructuring. These thoughts are quite common with anxiety and panic (thoughts of uncontrollability and unpredictability of future events, catastrophic thinking, etc). They would teach her how to reevaluate her thoughts and how to "test" their accuracy.