Pregnant Princess Kate Plans to Return to Royal Duties
09/29/2014 AT 08:45 AM EDT
The Duchess, 32, who has been suffering from a severe form of pregnancy sickness, has engagements lined up in October and leading up to Christmas.
But Palace sources are being cautious and will not confirm what the commitments are in case she can't attend. One source tells PEOPLE they are taking it on a "day-by-day basis" as they monitor her health. "There are engagements she would like to do over the coming months, but they are being reviewed daily," says a royal source.
Those dates would possibly come after she has passed the 12-week (first trimester) mark in her pregnancy.
The illness, hyperemesis gravidarum, which also affected her first pregnancy with Prince George, can be debilitating and very difficult emotionally, an expert says.
A Palace source has also told PEOPLE that the Duchess is able to be "up and about." Likewise, the fact aides considered her trip to Malta earlier this month hints that she was feeling better day by day.
Still, doctors ultimately ruled that she wasn't fit to travel, and husband William stepped in for her instead, telling people in the crowds that his wife was feeling "so-so."
Kate was also not by Prince William's side when he attended the wedding of family friend Victoria Inskip with brother Prince Harry on Saturday.
The Duchess continues to battle the effects of the illness and needs frequent rest, insiders have told PEOPLE. Add insiders: Any news of an official outing would likely be made with relatively short notice.