From the Guidelines
The normal heart rate range for pregnant patients is typically 70-90 beats per minute (bpm), which is about 10-20 bpm higher than non-pregnant women, as indicated by the most recent study 1. This increase begins in the first trimester and peaks during the third trimester. During pregnancy, a woman's blood volume increases by 30-50%, requiring the heart to work harder to circulate this additional blood throughout the body and to the placenta.
Key Points to Consider
- Tachycardia in pregnancy is generally defined as a heart rate exceeding 100 bpm, while bradycardia is considered a heart rate below 60 bpm.
- These changes are normal physiological adaptations to pregnancy and usually don't require treatment.
- However, persistent heart rates outside these ranges, especially when accompanied by symptoms like dizziness, shortness of breath, or chest pain, should prompt medical evaluation.
- Regular prenatal check-ups will include heart rate monitoring to ensure these changes remain within expected parameters throughout pregnancy. The study from 1 provides the most recent and relevant information on physiological changes during pregnancy, including heart rate. Although another study 1 discusses heart rate ranges for pregnant women during physical activity, it is not directly relevant to determining the normal heart rate range for pregnant patients at rest. Therefore, the recommendation is based on the most recent and highest quality study available, which is 1.
From the Research
Normal Heart Rate Range in Pregnant Patients
- The normal heart rate range in pregnant patients is not directly addressed in the provided studies, as they primarily focus on fetal heart rate. However, one study 2 mentions the maternal heart rate, stating that it rises from 79.3 beats per minute at 10 weeks to 86.9 beats per minute at 40 weeks gestation.
Fetal Heart Rate Range
- The normal fetal heart rate range is discussed in several studies:
- A study published in 2013 3 suggests that the normal fetal heart rate range is between 120 to 160 beats per minute.
- Another study from 2008 4 defines a normal fetal heart rate tracing as having a baseline rate between 110-160 beats per minute.
- A 1995 study 5 establishes heart rate norms for embryonic heart rates in the early first trimester, with the lower limit of normal being 100 beats per minute up to 6.2 weeks' gestation and 120 bpm at 6.3-7.0 weeks.
- A 1989 study 6 reports that normal first trimester fetal heart rates rise from an average of 100 beats per minute at 5 to 6 weeks to 140 bpm at 8 to 9 weeks.
Gestational Age and Heart Rate
- The studies suggest that fetal heart rate changes with gestational age:
- A study from 2019 2 found that maternal heart rate increases by 7.6 beats per minute from 10 to 40 weeks gestation.
- The 2013 study 3 notes that fetal heart rate decreases slightly during gestation.
- The 1995 study 5 establishes that the prognosis for fetal survival improves as heart rate increases up to a certain point, then plateaus, with this point varying by gestational age.