Id be demanding a swab. You are paying for a service (whether through PHI or thru taxes if you are going public) - this is the safety of your bub we are talking about.
If it is a leak you may need ABs too. Its not something to mess about with. If you are more assertive with what you want they may be more inclined to agree.
Im speaking form experience (different issue) I had to go in for monitoring multiple times with my first pregnancy.
I got all the first time mum looks and comments, but you know what I also got my healthy little boy.
First time mums can have complications, pre terms labours etc too, and you absolutely have to go with your gut on this.