My husband shared an interesting article with me recently.
I found this article fascinating because, even though the couple had been trying for a baby, they only realized mama was pregnant from Fitbit tracking. A Fitbit usually tracks your steps, heart rate, but some also track your sleep, flights of stairs, exercise minutes, and more.
You may wonder how a Fitbit could help this couple realize the mama was pregnant. I have since asked my mamas in our early pregnancy class if they have any ideas about it. Some know why, but many are surprised.
It picked up an increased heart rate over time.
When you are pregnant your heart rate increases because you are circulating more blood—for you and baby. The heart rate peaks in the second trimester.
There are many changes that will take place in your vascular system:
- Your blood volume will increase by almost 50 percent.
- Your red cell volume increases by about 18 percent.
- Your cardiac output increases 35-50 percent.
The highest cardiac output is between 28-35 weeks. These increases help your body provide oxygen for baby and meet the demands of your increased metabolism. The heart is also enlarged and displaced slightly by the diaphragm, which is pushed up by the growing uterus.
One side effect of this can be varicose veins, which are common in pregnancy, and are from the increased size of the blood vessels due to increased blood volume.
It’s normal in the beginning of your pregnancy for your heart rate to increase 15-20 beats per minute. This increase is due to the hormones involved in pregnancy—including estrogen and progesterone. Estrogen is thought to improve the vascularization to the uterus and placenta.
This same increase in heart rate is why, when you are exercising, we don’t use the “take your pulse for 10 seconds and multiply by six” method anymore, but encourage you to check your perceived rate of exertion. You should be able to talk while exercising when pregnant—not huffing and puffing so hard you can’t carry on a conversation.
Even though it is normal to feel your pulse higher in pregnancy, the following are reasons to contact your OB provider:
- Racing or pounding pulse.
- Fainting or extreme dizziness. (It is normal, because of the increased blood flow, to feel lightheaded and dizzy if you move quickly. I encourage moms, if possible, to make slower movements to avoid this.)
- Feeling of skipped heartbeats or an irregular heartbeat.
- Shortness of breath when you are not active. (Shortness of breath is normal with exertion in pregnancy. For example, you may notice that going up a flight or two of stairs makes you feel winded.)
- Persistent cough.