The mother and father were discovered by a cleaner who heard moaning coming from a private room on the maternity ward.
The worker told hospital bosses what she had found but was informed there are no rules against having sex on the ward at St Michael's Hospital, in Bristol.
The hospital's policy is for frisky couples to put a 'Do Not Disturb' sign on the door, The Sun reported.
A hospital source said: 'Other patients on the unit heard the commotion and were upset. The cleaner was utterly shocked. She was amazed to be told it was OK. The hospital's advice appears to be just to put a sign up - amazing.'
Like herbal remedies and eating spicy food, sex is said to help induce labour in some cases.
However, NHS advice says: 'You may have heard that certain things can trigger labour, such as herbal supplements and having sex, but there is no evidence that these work.
'Having sex won't cause harm, but you should avoid having sex if your waters have broken as there is an increased risk of infection.'
Source: UK Daily Mail