During pregnancy, the heart rate normally increases, so there is no single number that is automatically considered dangerous. Most healthy pregnant women have resting heart rates in the 80 to 90 range, and values up to about 100 to 110 beats per minute can be normal in late pregnancy. A heart rate becomes concerning when it is persistently higher than expected for pregnancy, especially if it does not settle with rest.
Pregnancy causes the heart to work harder to support the growing baby. Blood volume and cardiac output increase, which naturally raises the heart rate by about 10 to 20 beats per minute compared to before pregnancy. Because of this, mild and occasional fast heartbeats are often harmless. However, sustained tachycardia can signal an underlying heart rhythm problem or another medical issue.
Timing and symptoms matter. A fast heart rate that appears suddenly, continues at rest, or is accompanied by chest pain, shortness of breath, dizziness, or fainting is more concerning. Heart rhythm disorders during pregnancy are usually benign, but they are linked to higher risks when symptoms are significant or prolonged.
Anyone experiencing ongoing or symptomatic rapid heart rate during pregnancy should seek medical evaluation. A cardiologist or a maternal fetal medicine specialist may be involved. Self-medication should be avoided.