Hi..i have the same case as your wife. Was previously with a private doctor and diagnose with placenta previa at around wk 20+ (currently at wk 31). Doc suggest to go to gov hospital (he does not recommend kk lol) as there might be a major loss of blood during delivery. Before that i have experienced spotting twice n warded once at NUH. The doc at NUH have diagnose my case as major placenta previa too. There is really nothing we can do except for more bed rest, less movement and dont't carry heavy stuffs. I am currently on hospitalization leave.
We have chosen NUH as there is a blood bank there and in case of emergency blood can be easier available. Just a point to note. It is advisable to go in as a subsidy patient ( means we cannot choose gynae) first and upgrade later to private patient when your wife condition is more stable (means fixing a particular gynae) as the ICU charges for baby can run up to $100k or more should baby needs to be delivered pre maturely.
By the way, there is really no need to be warded as the doc there can do nothing except just to monitor ( for spotting) which you can do at home (judging from your post, your wife has not experience spotting which is good). No cause for concern. You can consider to switch gynae to NUH. Just call the hotline to book an appointment.
Relax enjoy the pregnancy and not be stress out which is the most important! Just like me!