The recommended limit of caffeine during pregnancy is 200 milligrams (mg) a day. So with a typical soda containing 35 to 55 mg of caffeine, it's wise to limit yourself accordingly, and take into account other sources of caffeine in your diet, such as coffee, tea, and energy drinks.
If you have a known heart problem, such as heart failure or heart disease, PVCs may be a sign that a dangerous heart rhythm could occur. So if you have a heart problem, talk to your doctor if you feel any change in your heartbeat. The cause of PVCs usually isn't known. But the chance of having PVCs can be increased by: 1  Having too much or too little of certain minerals (electrolytes) in your body. 2  Having too little oxygen in your blood, which could happen if you have COPD or pneumonia. 3  Using some medicines, such as albuterol.
However, if PVCs occur too frequently (more than several times per minute), the heart is unable to pump an adequate volume of blood to the body, which can cause symptoms such as weakness, fatigue, palpitations, or low blood pressure. Other types of rhythm problems can have similar effects. Problems may occur when the heart beats too fast, too slow, or with an irregular rhythm. But whether the heart is beating too fast, too slow, or too irregularly, the effects are often the same as one or more of those described above.