Duchess of Cambridge Kate Middleton, who is 18 weeks pregnant with her second child, will be unable to accept an invitation to join her husband, Prince William, when he travels to East Asia early next year, reports People magazine.

William, 32, and Middleton, 32, were invited to China in late February and early March, but doctors have advised against her traveling as she will be 8 months pregnant at that time. She is expected to give birth to Prince George's sibling in April.

William will visit Japan and China early 2015 on behalf of the British government, his office has announced. The purpose of the trip is to enhance "U.K.-Japan relations, commerce and cultural exchange," and "support of his own personal interest in combating the illegal wildlife trade."

Middleton will accompany William to New York on Dec. 7 where the royal couple will promote various charities and perform ambassadorial roles on behalf of the U.K. government.

The Duchess has had to cancel a couple of appearances due to hyperemesis gravidarum, a serious form of morning sickness that she has suffered the first three months of her pregnancy.

Pregnancy woes did not stop Middleton from shopping at local businesses on Thursday, reports Express.

Middleton enjoyed an afternoon of fresh air and retail therapy in the Georgia market town of Holt, Norfolk accompanied by her bodyguard and friends.

Chloe Nelson, who co-owns Nelson's Eye Patch store in Holt, posted pictures of the Duchess shopping to Twitter with the caption: "We spotted the Duchess of Cambridge on Holt's High Street today! #shoplocal #shopsmall #indieretail #northnorfolk."

The Royal Family has close ties with Norfolk which is where Anmer Hall, the couple's new home, is located.

On Tuesday, Middleton launched a fundraising event to build a new children's hospice in Norfolk. Patron of East Anglia's Children's Hospices, she educates and inspires the public to support the hospice's campaigns.