Translate the following English sentence to French:
"I particularly regret that Akin Birdal, whose health clearly continues to give cause for concern, was returned to prison on 28 March to serve his four-and-a-half month sentence."
Je regrette en particulier qu' Akin Birdal, dont l' état de santé continue visiblement d' être préoccupant, ait été remis en prison le 28 mars dernier, afin de purger sa peine de quatre mois et demi d' emprisonnement.