Sushi is raw fish, and like any raw food it is sometimes safe,
sometimes not. Zillions of fans can proclaim they have eaten
sushi for years and never had the least problem. On the other
hand, there are many bacteria, parasites and toxins that can
exist in raw fish. Some of these would make a breastfeeding
woman very sick; a few could pass through the milk. Reading
the descriptions, or spending too much time discussing it
with an infectious disease specialist -- or gastroenterologist
-- can make you want to stick with rice cakes the rest of
your life.

Tape worms thrive in sushi. I have personally seen them
wiggling around in a sushi (compliments of a friendly
infectious disease fellow who wanted to enlighten me.) If the
fish has been properly frozen and thawed parasites are killed.
The terrible 0-157 e. coli (the one that is famous for being
sold along with fast food hamburgers) has been reported in
sushi.

There is no one answer to whether or not sushi is safe while
breastfeeding -- or anytime. You pays your money and you
takes your chances, as they say.

Margery Wilson, IBCLC