Kate, 32, is waiting for her doctors to help decide if she can go to Malta this weekend. She was due to represent the Queen on a two-day trip to mark the 50th anniversary of Malta’s independence.
A Kensington Palace spokesman said: “The Duke and Duchess will make a final decision this evening, in consultation with the Duchess’s doctors”.
She has been suffering hyperemesis gravidarum, a severe form of morning sickness which also affected her while she was pregnant with Prince George.
Kate is reportedly eight weeks pregnant with a baby due in April.
