London: Duchess of Cambridge Kate Middleton is expected to take maternity leave from her royal duties and may not go on any official tours abroad after baby is born next year.
According to a report in The Telegraph, the Duchess will give birth to her first child next summer, meaning she is likely to be unavailable for any foreign trips before the end of the year.
No plans had been made for any overseas trips at the time she announced her pregnancy, and royal aides said it would be "unusual" for her to be asked to travel within a few months of the birth.
When the Duke of Cambridge was born in June 1982, his parents did not carry out an overseas tour for 10 months.
A royal source said: "The Duchess will give birth at some point in 2013 and it would be unusual for her to travel in the couple of months after that.
"No overseas tour has yet been planned for next year, and obviously the arrival of the baby will have an effect on the Duchess`s diary."
"If you take Princess Diana as an example, she took Prince William with her when she and the Prince of Wales went abroad a few months afterwards, so that would be one possibility."
The Prince of Wales and Diana, Princess of Wales carried out a six-week tour of Australia and New Zealand starting in March 1983.
Since the Duke and Duchess of Cambridge married in 2011, they have carried out long-haul tours to North America and the Far East in successive summers, but the timing of the baby?s birth is likely to mean the couple will not carry out another tour together until 2014.
One possibility is that the Duke could carry out a tour on his own, but this is only likely to be considered if he is asked to take on a relatively low-key visit within Europe.
The Foreign Office, which organises royal tours, is aware that Commonwealth realms such as Australia are eager to welcome the Duchess in the near future, and will be keen to wait until the Duchess can accompany her husband before arranging such a major visit.
The Prince and Princess of Wales`s decision to take the infant Prince William with them on their first tour after his birth is likely to be used as a precedent by the Duke and Duchess.
Whereas the Queen was left in England with her nanny for weeks at a time when her parents embarked on lengthy overseas tours, the prospect of the Duke and Duchess?s baby being left behind would be unthinkable in the 21st century.
The Duchess` pregnancy is also expected to lead to a delay in the announcement of her next batch of charity patronages.
So far the Duchess has only taken on four patronages, and had been expected to announce she was taking on at least as many again shortly after New Year.
Her severe pregnancy sickness has stalled her programme of private visits to charities which she is interested in supporting, meaning there will be no announcement until March at the earliest.
A royal aide said: "The Duchess`s private office is still working behind the scenes and work is progressing around her, so there is no sense that this has been mothballed."