Queen Elizabeth skipped Christmas Day church services after days of battling a heavy cold. Buckingham Palace said she need to stay home and recover but still planned on enjoying her family's Christmas Day celebrations.

Her unusual decision to miss church comes after she delayed her Christmas vacation last week because she was battling the cold. A palace spokesman said: "Her Majesty the Queen will not attend church at Sandringham this morning.The Queen continues to recover from a heavy cold and will stay indoors to assist with her recovery. Her Majesty will participate in the Royal Family Christmas celebrations during the day."

But the queen's health and recovery could mean more than skipping church service. Rumors have circulated for years that the 90-year-old queen is debating stepping down as the world's longest serving monarch. Most recently, Queen Elizabeth decided earlier this month to step down as patron from more than 20 national organizations by the end of this year. If she was no longer the United Kingdom's queen, that could clear the way for the royal who is next in line to sit on the throne. 

Prince Charles, the eldest son, has the title of Prince of Wales and is also known as Duke of Rothesay and the Duke of Cornwall. He has waited for decades to succeed his mother on the throne, but if he does become king, his wife, Camilla, will not be queen, after their extramarital affair when he was married to the popular late Princess Diana. Camilla would instead be known as the princess consort.

Charles' oldest son, Prince William, would then become the new Prince of Wales and the heir to the throne. His oldest child, George Alexander Louis, is now third in line to the British throne. The son of Kate Middleton and Prince William now carries the title of Prince of Cambridge.

So where does that leave Prince Harry, Charles and Diana's youngest child? The royal grandson is fourth in line to inherit the throne after his nephew's birth. 

It might be too early for Prince Charles to start planning his coronation, however. Nicholas Witchell, BBC News' royal correspondent, said the Queen's absence from Christmas Day service Sunday was a "precautionary measure" but there was "no sense of undue concern" from Buckingham Palace.