Bookmakers believe the Duke and Duchess of Cambridge will announce the pregnancy this year and have slashed odds in anticipation.
For instance, Coral currently has odds of one in two the royal couple will announce they are expecting another child by the end of 2019.
Coral spokesman Harry Aitkenhead made the following statement:
“Much has been made of Prince Harry’s comments that he and Meghan will most likely only have two children.
“However, we think Kate and Will’s family will continue to grow and make them odds on to announce a fourth baby in 2019.”
On the other hand, there are also clear signs that William and Kate are not expecting a fourth child.
The Duke and Duchess of Cambridge recently competed in the King's Cup regatta at Cowes, Isle of Wight, to raise awareness and funds for eight of their Royal Highnesses’ patronages.
Catherine steered her own Fast-40 boat in the competition - prior to a disqualification that landed her the wooden spoon - which revealed that she was not experiencing morning sickness.
According to Express, the Duchess of Cambridge suffers from a specific type of morning sickness named hyperemesis gravidarum (HG) which would have made sailing in a competition unbearably difficult.
Due to the fact the condition causes severe vomiting (which can occur almost 50 times a day) Kate was admitted to hospital on several occasions during her pregnancies with Prince George, Princess Charlotte and Prince Louis.
Therefore, odds are that the royal family isn't expecting a fourth baby in the immediate future.