While it might sound like this poor mom has what it takes to be the next Andrea Yates, it's important to understand that she's really just adjusting to the "fight or flight" stress hormones that for any new mom or mom-to-be are innate and incredibly powerful, Brizendine said.

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Beta blockers work by reducing activity in the sympathetic nervous system, which is one of the two major branches of the body's stress (or fight-and-flight) system.

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