The official announcement of the Duchess of Cambridge's pregnancy apparently has come from the Duke of Cambridge's Office at St. James Palace, not from Buckingham Palace. I'm probably the only one who's mind immediately goes to these things, but I wonder why? What things are issued by BP, and which are issued by the individual Royal Households?
Looking back through the press releases on the Monarchy website, I find that it was the press secretary for the Queen (Buckingham Palace) who announced the engagement of the Prince of Wales and Mrs. Parker-Bowles (the Princes' own household didn't). BP also announced the deaths of Princess Margaret and the Queen Mother, as well as the pregnancy of the Countess of Wessex and subsequent birth of Viscount Severn. BP even announced Peter Phillips's engagement (his mother's household didn't).
So why would St. James announce this pregnancy rather than BP?