Thanks for your query,
injection is given for fetal lung maturity in the cases where one suspects chances of preterm delivery before 34 weeks. Besides lung maturity , this steroid
also causes decrease in chances of necrotising enterocolitis and intra ventricular haemorrhage which are more common in case of preterm babies. .There are no siginficant side effect of this particular steroid in the mother as well as baby. It is definitely recommended in your case. So dont worry and go ahead.
Best of luck and take care..
Hope it helps..