Stress ALWAYS sends my husband over the edge.  He went through a period where he was really trying and WORKING with the tools given him in therapy to manage his stress.  I held out hope that this would progress and it would get easier for him to cope.  Unfortunately, he opted not to continue with the counselling, his family threw him a curve ball (they are a HUGE stress trigger for him) and it was back to the old cycles.

From what I've read and witnessed about BP traits, they certainly seem to have low to zero tolerance for stress, be it something unexpected or just the wear and tear of "life".  I know my husband hates schedule changes and would rage at me if there were additional activities or responsibilities in our lives.  

Definately stress as a trigger  :P

stress due to deadlines

stress due to too much responsibility

stress due to children being children

stress due to leaving for trips

stress due to unforseen circumstances

stress from things not going their way

stress from no one understanding what they are trying to say

stress from no one anticipating their needs (mind reading abilities)

stress from being the only one   who does things "the right way"

yes, stress is definately a trigger  :

Ocean, interesting.  I have hypoglycemia and if I don't eat at regular intervals, my blood sugar drops and my emotions go haywire: cranky, emotional (crying) and disoriented all at once.  It's not pretty. It takes me a few hours to regulate and get back in balance.  My exuBPDSO started to notice that her eating patterns impacted her emotional state, so she started to regulate the timing and quality of her meals.

In 12 steps there's a great tool called H.A.L.T. (hungry, angry, lonely, tired). The idea is that when I'm getting triggered, I need to stop (halt) and see if I'm under the "influence" of any of these 4 conditions. If so, I need to take care of it. Just having the awareness can help stop the spiral.

All of the above refers to acute stress.  The Cleveland Clinic goes a lot further saying that stress plays a major role in triggering the development of BPD in a person - childhood trauma, such as abuse, neglect, prolonged separation, or inconsistent parenting.

The exact cause of borderline personality disorder is not known, but most researchers believe that it is caused by a combination of biological and psychological factors. People with this disorder might be born with a vulnerability to the disorder, which is then triggered by stress or other factors.

For example, research suggests that a malfunction in the brain might be responsible for the impulsiveness, mood instability, anger, and negative emotions that are common in people with this disorder. Psychological "triggers" might include childhood trauma, such as abuse, neglect, prolonged separation, or inconsistent parenting.

A disruptive family life and poor communication within the family also are risk factors for the development of BPD.

I've seen stress trigger my SO's uBPDxw, some of the stressors are from outside sources, friends, family etc.   But what I see the most are situations that she creates herself, renting a town house she can't afford and being evicted, sending a daughter to camp that she didn't/can't pay for, bouncing a check and having to go to court, or not paying income tax for example.  Not thinking or realizing the consequences of her actions.

Yes, her particular brand of BPD involves a lot of dysfunction around money and appearances.

I understand her reasons behind the things she is doing and can have compassion for her from that stand point, but her actions create stress for not only her but those around her.

It becomes a vicious cycle of dysfunction creating stress and stress creating elevated dysfunction. 

Panda39