Talk to Gynecologist on Pregnancy Progesterone Level

Dear drs, assalam o alaikum, my sister 29, is pregnant, its her first pregnancy, the problem is she had her blood test done on 25th February, abd the progesterone level came as 12.99ng/ml, dr said its low and asked her to repeat the test on 27, the progesterone level came as 12.33 on 27. dr, advised her to take progestetone injection 1 a day and 1 tablet as well, now the question is is this treatment okay? or can she take tablets only? her last menstrual period date is 21st January, 2023. she had no bleeding or any other problem. Would really appreciate your guidance