Spinning is a stationary format of high-intensity cycling (usually indoors but can be outdoors) that generally takes place on a stationary machine with a heavy, weighted flywheel that is linked to the pedals. It is a cardio (aerobic) workout often set to music and led by a certified instructor. Most spinning classes last for 30-60 minute sessions. The intensity of spinning varies throughout the class thanks to different body positions (i.e., standing versus sitting), pedal speed, and resistance.
Exercise is generally good
Exercise during pregnancy is almost always a positive practice with many benefits. It has been thought to help prevent gestational diabetes, make labor much easier, and prepare your body for a quicker recovery.
Spinning and your balance
Even on a stationary bicycle, it is essential to keep your balance. Keeping your balance may be more difficult when you are pregnant, especially later in pregnancy. Balance is a large issue during pregnancy, particularly in the advancing months. In early pregnancy, hormonal shifts cause many women to feel lightheaded and dizzy which raises their potential for falling. In the second and especially the third trimester, your center of gravity from your growing belly will be off and your regular balance while riding can be largely unsteady. One quick plunge from your bike could easily cause trauma to your stomach, which could injure the baby, or placenta, or lead to premature labor.
As the pregnancy develops, it becomes more difficult and riskier to ride and in your final trimester, it may become complicated to maintain your balance thus introducing additional possible falls from off your bike.
In many cases, doctors usually indicate that you can get a good of a workout with a safer exercise or sport. The potential to fall and cause injury to your belly is just too great to risk it.
Precautions for spinning during pregnancy
You can easily get dehydrated while spinning, especially during pregnancy. Dehydration can have a significantly negative effect on pregnancy and the fetus. Drink enough before you start spinning, and drink every 5-10 minutes while spinning.
When spinning you work up a sweat, so always wear light and cool so to not to sweat too much.
Get to the spinning class early or reserve a set. Adjust your saddle. Getting the perfect fit on the bike can be tricky, but a general rule of thumb is to adjust the seat to be even with your hip. As for the handlebars, position them so the neck and back don't strain. And strap or clip in the feet: The balls of the feet should rest on the center of the pedal and if you're strapping in, make sure they're secure.
Keep a towel draped over the handlebars for easy access—you'll probably need it. Do not go for sessions where the room is warmed up. Instead, stay in a cool room.