Hi Chickibud
I don't think there is anything you can do to avoid it - it is down to how your liver metabolises the hormones produced during pregnancy, so you kind of need them for growing your baby! But if you find anything, let me know for the next time I'm pregnant!
But there is no guarantee you will get it again - research ranges between 30-90% recurrence rate, with 50% most often quoted - so you could be one of the lucky 50%!
I was one of the unlucky 50%, but I had it much worse and started much earlier in my 1st pregnancy - it came on much later and much milder with my 2nd pregnacy, so it may be not be worse this time around - in fact the itching tailed off pretty quickly and I felt like a fraud, but as my liver enzymes were up, I was induced at 38 weeks. [very glad as I was, as DS was 8lbs9.5oz, with a very big head, so pretty glad I wasn't allowed to go 10 days overdue!!]
Try not to let the worry of this spoil the rest of your pregnancy, but obviously keep an eye out for the symptoms - I found acqueous cream with menthol soothed the itching this time around. It is better to be safer than sorry, I think with regards to this, as they don't really know much about it yet. There is a good support website that discusses some research into OC - you could try e-mailing them for more info on anything that could help you? Not sure of the link, but just google OC support site and hopefully you'll find it.
Take care and keep thinking, 50% lucky!