The centre-back, who recently made his Champions League debut against Young Boys in the 1-1 draw at Old Trafford, embarks on his second temporary move away from the club.
The Manchester-born prospect spent the second half of last season at Derby County, where he worked under the management of United’s all-time leading goal scorer, Wayne Rooney.
Mengi is an England Under-20 international who has captained United throughout the age groups.
The move will reunite Teden with fellow Academy graduate Tahith Chong who is also on loan at Birmingham. However, the winger is currently undergoing treatment at Carrington for a groin injury that he suffered earlier in the season.