Hi Nic
I am not a medical professional, simply a mother who maintained a decent level of activity while trying to fall pregnant, while having a miscarriage and throughout my subsequent successful pregnancy.
I was certainly not cycling at the level that I do now, but was swimming quite heavily, walking/jogging a fair bit, and tap dancing in preparation for an exam. I have always been somebody who likes to exercise hard and didn't back it off because I wanted to get pregnant. Similarly, I have a friend who runs keenly and ran up to and through her pregnancy with full blessing of her doctor.
It is my understanding that, unless you have some underlying medical condition, and unless you are exercising to the point where you are not healthy (ie. seriously underweight and hormonally unstable - not having your periods etc) then it is unlikely to affect your chances of falling pregnant and unlikely to stop you maintaining a viable pregnancy.
In my case, the pregnancy I miscarried was never going to be viable and a change in my exercise patterns was not going to change that. And the successful pregnancy went swimmingly with me completing my tap dancing exams at 12weeks pregnant, continuing tapping, walking and swimming up until the week I had her.
I tapped in 2 groups in our annual concert (including one with the teens I did the exam with) when I was 6months pregnant, four weeks after my emergency caesar delivery I danced in demonstration event and then did the next exam when the DD was 16weeks old. The doctors were very happy with my level of activity throughout and believe it helped me recover so well from the caesar that I was not very amused about having!
I think people like to scaremonger and make you feel guilty about your choices. While you want to give yourself the best possible chances of falling pregnant, exercise at a level that is normal for you and not making you unhealthy is not likely to be a real problem. Once you are pregnant (good luck with that btw) you will end up slowing up a bit and you will need to be guided in your individual circumstances by your doctor who knows you. I must admit that I don't find 200km/week to be excessive, especially when rationed out through the week nice and consistently as a commute (seems like about 20km each way, 5 days a week?) I would be much more worried if you sat on the couch all week and then ran out and did your 200km in one ride each weekend!
Now, I wouldn't take my word for it - these are simply my circumstances which would suggest you'll be fine! If I were you, I would have a nice long talk to your trusted family doctor - or if you don't yet have one, you better develop a relationship with one because you'll visit them often enough when you have kids! They should be able to assess your current health and prospects and give you sound advice on "how much is too much?"
Good luck!