An American inmate and his Thai wife who escaped from custody are still being treated in an intensive care unit as they are in serious conditions, a doctor said on Thursday.

The hopital director said both Bart Allen Helmus and his Thai wife  Sirinapa Wisetrit are still in the ICU and their conditions were serious.

In another interview, the hospital chief said the woman was suffering from bleeding in the brain and she was not pregnant.

The doctor was responding to earlier police reports that the American might have decided to escape after learning his wife was pregnant.

"She told us she was not pregnant," Dr Puwadol said. "The woman could be stressed, which might have caused missed periods."

The American, his Thai wife and another Thai prisoner Noi Nilthes fled from the Pattaya Court on Monday, injuring a police officer on duty at the courthouse. 

The three were arrested in two different locations on Wednesday in Sa Kaeo province.

Mr Helmus resisted the arrest. When they were surrounded by police, the American fired one shot at his wife and then turned on himself. The couple were sent to the hospital.

Police added 10 people who knew Mr Noi were involved in their escape in which five vehicles were used. One of them, Warakorn Ditthamalee, was later caught.

Mr Warakorn allegedly gave a pistol to Mr Noi when he used one of the vehicles to visit him at the prison. Mr Noi used the gun to shoot Pol Capt Thanamet Photipan, who was on duty at the courthouse after the officer refused to give them the jail keys and Mr Helmus stabbed him with a knife.

After the escape, they went on a pickup truck which stopped in Chon Buri. Their accomplices cut the chains and put them in another pickup truck, which dropped Mr Helmus and his wife in Prachin Buri. A car then took the couple to Sa Kaeo. Another car was seized before it would be used to send Mr Helmus and his wife to cross the border to Cambodia.