Prince William and Kate Middleton
Kate Middleton leaves the hospital quicker than Princess Diana after royal birth. Pictured: Prince William and Middleton pose for photographers with their newborn baby boy outside the Lindo Wing of St Mary's Hospital on April 23, 2018 in London. Getty Images/Jack Taylor

Kate Middleton is out of the hospital just hours after giving birth to her newborn.

According to People, the Duchess of Cambridge only spent 12 hours in the hospital for the delivery of her third child. In fact, she stepped out just seven hours after giving birth.

Middleton has been known for her speedy hospital exits. When she gave birth to Prince George and Princess Charlotte in 2013 and 2015, respectively, she was also in and out of the facility within 12 hours. Although she spent one night after delivering her eldest, she left in less than 24 hours.

Meanwhile, Princess Diana usually took longer to depart from the hospital after delivering her sons. When the late Princess of Wales delivered Prince William in 1982, she didn't leave the facility on the same day. Prince William was born on June 21 and was introduced the following day. The same applied to Prince Harry.

There is actually no royal protocol when it comes to post-birth exits. However, Middleton reportedly wanted to leave the hospital immediately because she knew that her presence would cause a frenzy outside the hospital, which can be disruptive to other patients.

The media and the photographers usually camped outside the Lindo Wing to capture Prince William, Middleton and their newborn. Tim Rooke, a royal photographer, previously said, "the media positions were sorted out two weeks before the birth."

They had to wait for Middleton's admission before they were allowed to take their positions outside the hospital. "Because it is a working hospital, nobody is allowed into those positions until we're told that the Duchess of Cambridge has been admitted," Rooke explained.

In addition, Middleton has access to a medical team and prefers to be in the comfort of her own home. Prince William and Middleton also have a baby team that includes her mom, Carole Middleton. The group is "dedicated to making sure everything is ready, from media plans to security to hospital arrangements. There's a backup plan for everything."

In related news, Prince William and Middleton are reportedly strict when it comes to their children's privacy. In fact, they planted 40-foot hedges in front of Kensington Palace so Prince George and Princess Charlotte can play outside without being seen from the gates. The royal couple also implemented a "no-fly zone" around their estate at Anmer Hall to avoid helicopters and drones getting photos of the royal kids.