Toddler tantrums affecting baby in the womb?

Just curious about people's thoughts about this. I know stress can affect the baby in the womb and the baby can hear (20weeks) through my tummy. My concern is that the baby is going to hear the toddler I work with tantruming / crying and feel my stress levels going up and it will train them in the womb to have a bigger reaction to crying and screaming. Does that make sense? I'm normally the most patient person in the world, but ever since getting pregnant, I just can't seem to control it, it makes me so angry when they scream for no reason. I'm one who reasons them out of a tantrum and recently I have just been getting frustrated. I guess I want to see what your coping strategies are for dealing with the stress and also to see what your opinion is, if you think it's a valid concern that the baby will come out knowing that tantrums illicit those kinds of physiological reactions and thus tantrum to get their way more?