Your pulse — also called your resting heart rate — usually changes during pregnancy. Although this is a normal part of being pregnant, it's helpful to keep track of these shifts. Similar to other health indicators, like blood pressure, it can give you a snapshot of your health during pregnancy.
Read more: A Healthy Pulse for Women
Calculate Your Pulse Rate
According to the American Heart Association (AHA), you can calculate your resting heart rate by placing your finger on your wrist, the inside of your elbow, the side of your neck or the top of your foot. Your pulse should have a strong, steady beat.
Measure your resting heart rate first thing in the morning, ideally before you've gotten out of bed. Use a stopwatch or a clock with a second hand to keep track of the time. Count the number of beats during a 60-second period.
Why Heart Rate Changes
During pregnancy, your resting heart rate will rise slightly as the months pass, because the heart is pumping more blood throughout the body than usual, according to G. Thomas Ruiz, MD, an obstetrician/gynecologist at MemorialCare Orange Coast Medical Center in Fountain Valley, California.
"As soon as a woman gets pregnant, hormones are flooding the body, and that causes the peripheral vascular system to relax, with corresponding compensation in plasma volume," Dr. Ruiz says.
Basically, you have more "space" in your veins and arteries because hormones are prompting a relaxation response, he says, so your body tries to fill that space, and it requires more blood to be pumped out at a faster pace. But what you'll likely feel as that happens isn't a racing pulse, Dr. Ruiz says, but a sense of fatigue.
"This is one of the reasons many women feel so tired, particularly in their first trimester as you're trying to adjust to this change," he says. "The pulse rate may be slight, but there's a great deal going on, and it's helpful to rest more often as your body adjusts to these shifts in function."
Although the pulse rate increases because of pregnancy, it's a very poor pregnancy test because the increase is slight. Also, the AHA says, your resting heart rate can change due to other factors, such as air temperature, body position, medication usage and even strong emotions.
Increases Each Trimester
A normal resting heart rate for an adult ranges from 60 to 100 beats per minute, says AHA. During pregnancy, a woman's resting heart rate can increase 10, 15 or even 20 beats per minute, says the National Academy of Sports Medicine.
Heart rate tends to rise as pregnancy progresses, explains Dr. Ruiz. For example, it may rise by about five beats a minute over your non-pregnant rate in your first trimester but be up by 15 beats a minute by the third trimester.
Keep in mind that being athletic may change these numbers, says Tina Nguyen, MD, an obstetrician/gynecologist and assistant professor at the David Geffen School of Medicine at the University of California, Los Angeles. If you've been a regular exerciser, it's likely you'll start with a lower heart rate, she says.
"Someone who's athletic may have a resting heart rate of 50, with a peak resting heart rate at typically 63," she says. "Resting heart rate maxes out at 95 in the third trimester. If a pregnant woman's pulse is over 100, that should be evaluated."
Read more: Know the Causes of an Elevated Heart Rate
When to See a Doctor
Feeling out of breath and having a higher heart rate is normal in most pregnancies, Dr. Nguyen says, but it's important to get checked if it seems like your pulse is increasing rapidly or if it goes over 100 while at rest.
If you can feel your heart beating fast, have significant shortness of breath or any chest pain — especially after resting and drinking water — Dr. Nguyen suggests letting your doctor know right away. Some pregnancy-related conditions, such as blood clots and anemia, could be present, she says.
- American Heart Association: “All About Heart Rate (Pulse)”
- G. Thomas Ruiz, MD, obstetrician/gynecologist, MemorialCare Orange Coast Medical Center, Fountain Valley, California
- Tina Nguyen, MD, obstetrician/gynecologist, assistant professor, David Geffen School of Medicine, University of California, Los Angeles
- National Academy of Sports Medicine: "Exercise and Pregnancy: Physiological Changes and Exercise Programming"