Can Taking Betnasol Inj In Pregnancy Harm The Fetus?

i am in the 28th week of pregnancy. My doctor has asked me to be on bedrest as my cervix measures 2.8. I have been taking duvadilon inj ,tidilon and utodin tablets regularly. Now docotor has prescribed me to take betnasol inj once a weeek. Now since betnasol is a steriod and has a side effect on the baby's development, pls adv me if this is necessary?