Telling Work Related Contacts

I have a few supplier contacts I deal with regularily and was after some suggestions on when and how would be best to let them know that I am pregnant. It would most likely be via email or phone as this is how we normally communicate.

I was thinking I might wait until I knew who would be taking over that part of my job while I am on maternity leave.

My biggest problem is my Japanese and Korean contacts who all call me "Mr". I felt funny about correcting them when the original mistake was made and now I feel even worse about having to tell them I am actually a female and pregnant as this has gone on for a few years now.

All advice most welcome.

I think waiting until you know who's going to replace you sounds very sensible. You wouldn't even have to say you were going on maternity leave if you felt uncomfortable with it, I think it would be fine to just say you are going on leave, and they should contact person X until you return.

I would wait and send out a letter or phone them advising the new contact.
Some of my closest suppliers I told when I spoke with them on the phone. As for the Korean contacts calling you 'Mr', do you need to tell them you are pg or could you just tell them you are going on leave? Might be better business wise if they think you are male?