The cause of the build up of fluid, known as acute pulmonary edema, could be linked to a cardiac problem, a French coroner has said. Other toxicological analysis is under way.
Munster head coach Foley, 42, died on Saturday night at the hotel in Paris where Munster were staying prior to Sunday’s scheduled game against Racing 92.
His funeral will be held in Killaloe, Co Clare, on Friday.
Foley made 201 appearances in the back row for Munster and won 62 Ireland caps.