Since you asked.  I happen to know a little about what is thought
about breastfeeding while pregnant in Japan.  I was living in
Japan breastfeeding my 1 year old while pregnant with my second
child.  At my first prenatal visit I was asked if I was still
BF and then told to stop because I would not be able to "keep up"
with the needs of my 1 year old and the new baby.  At the
next visit I was asked if I had weaned and I said yes just so
I would not be scolded.  I continued to breastfeed and even
tandem nursed after my baby was born.  Getting through months
3-6 were tough because my breasts and nipples were so sore but
the emotional well being of my first child was worth it.

--
Becky Hanson, BA, LLLI, AAHCC, ICEA & MOM X 2