if they had caught it earlier they could have given her some drugs for his lungs
These would have been steroids to mature his lungs. Babies born under and around 24 weeks gestation do not really have the lung capacity to survive after birth, so if they suspect a possible preterm birth, they give steroids.
she said it happens to 1-2 people in every 100
Bollocks. 
I don't know where those figures actually come from, but they seem comically high. It would mean that there were 7500 IC-related second trimester losses in the UK every year, and err ... there just aren't.
Put it this way, my local hospital oversees 5000 births a year. I was the only IC case some of the consultants, and all of the midwives, had seen in their careers. The regional obstetric consultant that looked after me during my successful pregnancy, who is also one of the handful of consultants that specialises in IC in the UK, only surgically treats about three or five IC-affected women a year out of tens of thousands of pregnancies in our region.
The NHS website it states D&C procedures put you at a higher risk.
What you need to remember here is that not all D&C procedures are the same. The statistics that inform the notion of D&C procedures increasing risk could very well be referring to D&Cs done twenty years ago when procedures were different, or D&Cs that were particularly invasive.
Total naivety on my part that if they could scan or monitor something then they would. It's surprised me you have to lose a baby first.
You simply could not properly scan every pregnant woman for IC in the UK every year. It would cost a fortune. You are talking about an extra seven to eight scans per pregnant woman with the associated sonographical training.
To give you an idea of where the land lies with this, an IC support campaign group are just, at the moment, trying to work towards getting a consistent IC treatment pathway in place for women that have already had one or two suspected IC losses.
From what I understand it's painless with hardly any symptoms
This depends. My first IC loss was preceded by nagging constant abdominal discomfort and pain from about 16 weeks before my waters broke at 20 weeks.
I apologise for asking what appears to be a stupid question.
It was, most emphatically, not a stupid question. There are a lot of misunderstandings about the condition and the more people know, the better.
That you are already 23 weeks is an incredibly good sign. I really would not worry too much if I were you, but I know that is easy to say and very difficult to do.