Andrea is right.

Other than that, your pregnancy is incredibly protected. While people like to speculate that they miscarried because they did this, or because they did that, the fact is, most miscarriages are a result of something being wrong from the beginning: ie. bad sperm or bad egg.

We worry about falls with the third trimester because there is a risk of placental abruption, but it is rare. Also, if you exercise during the third trimester, make absolutely sure that you drink plenty of water. Edging towards dehydration can cause false or early labor. You'd probably prefer to go through labor only once. The balance issue is probably the best reason to take it easier during the third trimester. Consider walking instead during the last two months.

Most importantly, buy your kid a bike.

Congratulations!