Switching after 20 weeks is very doable, someone in my mum group actually made the switch at week 32 from subsidised to NUH private, mainly for the A-class ward and to finally have a consistent gynae throughout, so 20 weeks gives you even more runway. From what I heard, NUH private caesarean starts around $12,000 before ward charges, so do factor that in alongside your Medisave and insurance coverage. The honest part though, a few mums felt the waiting time at NUH subsidised was the real pain point, but going private does help with that since you get a named gynae who follows your case; just know that even in private, some delays can still happen on busy days. If you are set on a specific doctor, it is worth calling NUH early to check availability and get a clearer cost breakdown from their billing team directly, because the numbers can vary quite a bit depending on your delivery details.