Cycling & Weightlifting During Pregnancy: Safety & Benefits

Question
I started cycling in may and have continued up until I found out that I was pregnant on Oct. 20.  Is it okay to still cycle and lift weights?

Answer
Cycling is a great non-impact aerobic fitness activity and since you are acclimated to that level of exertion, you can maintain a high fitness level throughout your pregnancy. Both you and your baby will reap tremendous benefits. But...most experts agree that road cycling is not worth the risk so take your cycling workout indoors. Yes, it's not as fun, but it's only for a short period of your life.
You can cycle indoors until your belly gets in the way, then for aerobics, switch to a treadmill or elliptical trainer. I don't recommend stair-steppers in the last half of pregnancy, as the amount of rotation required in the lower back can strain the sacroiliac joint. Swimming is also an ideal fitness activity in the later stages.
Be aware that the placenta stops growing at 20 weeks gestation and at this point it's functional capacity to utilize oxygen is capped. So after 20 weeks, begin slowly taper down the intensity of your workouts to stay in your proper aerobic training zone. You'll find that as your baby grows rapidly in the last trimester, that she will demand more from you, and that you'll need to further reduce the intensity of your workouts. Always stay in an aerobic zone where you rate the intensity as 'somewhat difficult.'
As to weight lifting, moderate level is OK, but nothing super heavy like dead lifts, or the clean-and-jerk. Shift your focus to core training, rather than all machine work.