After reading your question, I searched the net and found a report from a health authority in Holland who are advising their GPs not to prescribe Yasmin (by Schering) until further tests have been conducted. The reason for this is a higher then usual number of women suffering dvts (some fatal). In the big picture of things this is still a small number.
However, I contacted my doctor who told me that it is a new drug and though it has been tested there is not a track record of its side effects, and current users are a bit like 'guinea pigs'. He advised me to change to another pill which has been around for a little while longer, until further evidence it is safe has been published. The site I found this report on is stated below.
http://bmj.com/cgi/content/full/324/7342/869?view=
full&pmid=11950727
I
hope you find this useful.