Hindi ako sure kung may specific requirement talaga, pero from what I've heard from a few of my mum friends, it really depends sa hospital mo, some required the swab a few days before admission, iba naman during labor na mismo or right after delivery, kaya best talaga to ask your OB directly kung anong protocol nila para walang hassle on the day! Some hospitals also accepted recent negative results from weeks prior depending sa situation, pero honestly mas safe na i-clarify mo with your medical team para sure ka na.