viks
welcome to the thread!
how long have you been running for? general conventional medical wisdom (ie not your granny but the doctor/midwife) says that, as long as you've been running for a while (usually more than 6 months), it's fine to continue while you are trying and also while you are pregnant. so no need to stop at all, as long as everything goes well and you feel fine.
if you are running lots of miles or are very underweight, you may not be ovulating. but assuming you are not underweight or overtraining, you should be fine.
as for 'shaking the egg lose' - there's no evidence to suggest that runners have any higher an occurrence of ectopic pregnancies, miscarriages, implantations outside the womb than the general non-running population. the egg is absolutely tiny and burrows itself very deeply into the lining of the womb, and once it's there, it won't be shaken lose by the impact of your running. therefore, unless there are other complications, all the books i've read have said that you will not be putting yourself at a greater risk of miscarriage by continuing to run, as long as you feel well.
several of us on here were running quite long distances in the very early days of our pregnancies (before we even knew we were pregnant), and everything was fine. i did an 18 mile run one weekend and a half marathon race the following weekend and then found out i was pregnant 10 days or so after that, so my 18 mile run must have been the weekend i actually got pregnant.
you may find that once you are pregnant, you feel too grim to carry on running, but you'll just have to see how it goes.
good luck anyway, and pop in and see us again!