ROTS was always written to only take place over about a week.
The novelization of the film gave it a 2-3 month period.
But let’s say it always was supposed to be 3-10 days. Padme really didn’t tell Anakin for 8-9 months that she was pregnant? The way they talk about “going early to naboo to get the baby’s room ready” is not what someone who’s giving birth in two weeks would say. It just doesn’t work based on how pregnancy maps out.