Kar,
I truly understand how worrying it is... Cord accidents happen but rarely. Kinda like we could get struck by lightening but it's unlikely - do you know what I mean?
Please don't think I am understating your anxiety - trust me I have a suitcase full if anyone wants some pregnancy baggage! But so it's in perspective for you it is rare.

You are half way!!! It must be so wonderful to feel your baby moving around. I am HANGING out for then.

Take care...