Hi, I had IUGR with my first duaghter, at around 32 weeks they noticed that her growth was falling behind, so as kiki said they kept a close eye on her by doing weekly u/s's when I reached 36 weeks and she was still not growing as much as she should have they decided to iduce labor, in my case I didn't dialate enough and ended up having a c-section. they also gave me a steriod injection a few days before the induction to help the baby's lungs mature.
Tell your sister in law not to worry, the most important thing is that they diagnosed it in time to keep a close eye on her and her baby.
My duaghter is now almost 6 years old and thank God in great health
If you have any other questions I'll be glad to answer I did alot of research at the time
They should do a follow up u/s in a week to check for any progression, if there has been none, her OB will probly opt for delivery. There is no other procedure to help, other than birth. Good luck to you.
sry i'm not gonna be much help but all she can do is what the doctor recommends