Happy that ur short cervix was detected on time. U have already passed 7months. That's a great news. Regarding precautions, bed rest and continuing ur medicines as per doctors advise is very important. Also u need to have good fluid intake so that constipation and urinary infection is prevented. Eat heathy home cooked fresh food so that u prevent any stomach upset which can trigger preterm labour. Pls do also bear in mind that bed rest related inactivity can lead to weight gain and increased blood sugars etc. So restrict ur dietary sugar load