You are going to have a baby! For many women, the first, tangible realization of this major milestone comes with an ultrasound. The image of the baby’s heart – visible as a tiny, pulsing speck on an ultrasound monitor – is immensely moving. But there’s much more going on than you’d ever imagine. The fetal heartbeat plays a crucial role in the health of your baby – during pregnancy, birth, and beyond. Fortunately, the technology used to monitor your baby’s heart offers vital information that can indicate the viability of a pregnancy and detect congenital heart abnormalities early on.
When Does A Fetus Develop A Heartbeat?
The baby’s heart – initially a tube-shaped structure that develops into the chambered organ we are familiar with – begins to form early on, in the days after fertilization.1 Here’s a rough timeline:
- Week 3: Fetal heart begins to form at day 22 after
- Week 5: Fetal heart chambers start to develop.
- Week 6: Heart rate increases to 100–160 beats per minute (bpm). This is when you can see the baby’s heart beating during prenatal ultrasound monitoring.
- Week 8: Baby’s heartbeat has a steady rhythm.2
- Week 10: Heart rate increases to about 170 bpm and stabilizes at about 130 bpm close to the time of birth.3
What powers the baby’s heart to begin beating? What controls the speed of the first tiny flutters? According to scientists, the answers to these mysteries could hold the clues to our understanding of congenital heart defects and their treatments.4
What Is A “Normal” Heart Beat For A Fetus?
Medical opinion varies considerably about what constitutes a “normal” heart rate
If the arrhythmia persists, however, your doctor will turn to echocardiography to take a sonogram of the heart, assess the condition, and
Devices To Monitor Fetal Heartbeat
Monitoring the fetal heart involves measuring its heart rate and rhythm. This helps doctors check on a baby’s development. Here’s a quick look at devices used in modern medical practice:
- A fetal Doppler, using an ultrasound probe that is moved over the mother’s belly, bounces sound waves off internal organs. The rebounding echoes are translated by a computer into patterns that are visible on a screen. However, this device does not display images.
- During the sixth week of pregnancy, your OB/GYN may use a transvaginal ultrasound to check on the baby’s heartbeat. In this method, a probe is gently inserted into the mother’s vagina. The sound waves echoing off the uterus are converted into images that display the fetal heart beating and provide readings of the number of beats per minute. This method helps the doctor determine the progress of the pregnancy.
- At times, external methods don’t yield
Is Fetal Heart Monitoring A Must?
Fetal heart monitoring is now a part of routine check-ups. In high-risk pregnancies, heart monitoring becomes even more important. Some situations where monitoring plays a crucial role are:
- If a mother is diabetic or has high blood pressure.
- If the baby’s growth rate is slower than desirable.9
- If medications given to prevent early labor may have impacted the baby.10
For a new parent, a baby
Timing is also an important factor here. Fetal heart monitoring can help doctors determine if treatment for a baby’s heart defect can be delayed until after birth or if it requires intervention soon after delivery.
A heart rate that is above normal (known as tachycardia) and below normal (bradycardia) could be a cause for concern.12 A below normal heart rate in the first trimester could indicate that the pregnancy may not reach full term.13 There’s also a possibility that an excessively high or low heart rate in early pregnancy could be linked to different types of abnormal chromosomes in the baby.14
How Can You Help Your Baby’s Heart Development?
While genetics play a large part in the development of a baby’s heart, there’s plenty you can do to help keep you and your baby healthy, like eating fresh, wholesome food, getting enough sleep, and managing your stress levels. Here are a few other things to keep in mind:
- Take folic acid supplements before and during your pregnancy to help prevent the development of congenital heart disease15
- Aerobic exercise during pregnancy influences fetal heart rate. Using ultrasound technology, researchers have concluded that moderate and regular exercise through pregnancy leads to a lowered fetal heart rate
- Ayurveda offers advice on specific foods to be consumed during every month of pregnancy, correlated to the baby’s development. Ancient ayurvedic texts also list a vast range of cereals, pulses, “fruit vegetables” (pumpkins, kidney beans, peas, and tomatoes), root vegetables and tubers, milk and milk products, meats, herbs, and aromatic spices to promote the health and strength of both mother and baby.19
- Are you a smoker? Then it’s time to quit – now! There’s a mountain of evidence proving that smoking just before pregnancy or during the first trimester could lead to heart defects in the baby.20
- Diabetic moms run the risk of having babies with congenital heart disease. If you are diabetic, carefully follow your doctor’s advice on how to control your blood sugar.21
Fun Fetal Facts
- The various periods of growth and development of a baby during its first eight weeks of life is referred to as the “Carnegie Stages.” In all, there are 23 Carnegie Stages.22
- During the first eight weeks, the baby is referred to as an embryo (“growing within”). From eight weeks to the time of birth, the baby is a fetus or “unborn offspring.”23
- A baby’s heart beats 54 million times from the time it is formed to the moment of birth.24
- At 6–8 weeks, the fetal heart has grown into four chambers. Its development is nearly complete and it beats rapidly at about 167 bpm.25
|↑1||Moorman, Antoon, Sandra Webb, Nigel A. Brown, Wouter Lamers, and Robert H. Anderson. “Development of the heart:(1) formation of the cardiac chambers and arterial trunks.” Heart 89, no. 7 (2003): 806-814.|
|↑2||Pregnancy. Office on Women’s Health, US Dept. of Health and Human Services.|
|↑3, ↑6||Fetal heart rate. Radiopaedia.org.|
|↑4||Tyser, Richard CV, Antonio MA Miranda, Chiann-mun Chen, Sean M. Davidson, Shankar Srinivas, and Paul R. Riley. “Calcium handling precedes cardiac differentiation to initiate the first heartbeat.” eLife 5 (2016): e17113.|
|↑5||von Steinburg, Stephanie Pildner, Anne-Laure Boulesteix, Christian Lederer, Stefani Grunow, Sven Schiermeier, Wolfgang Hatzmann, Karl-Theodor M. Schneider, and Martin Daumer. “What is the “normal” fetal heart rate?.” PeerJ 1 (2013): e82.|
|↑7||Weber, Roland, Dominik Stambach, and Edgar Jaeggi. “Diagnosis and management of common fetal arrhythmias.” Journal of the Saudi Heart Association 23, no. 2 (2011): 61-66.|
|↑8, ↑10||Fetal Heart Monitoring. John Hopkins Medicine.|
|↑9||Special Tests for Monitoring Fetal Health. American Congress of Obstetricians and Gynecologists.|
|↑11||Detection of a Heart Defect in the Fetus. American Heart Association.|
|↑12||Detection of a Heart Defect in the Fetus. American Heart Association.|
|↑13||Benson, Carol B., and Peter M. Doubilet. “Slow embryonic heart rate in early first trimester: indicator of poor pregnancy outcome.”
|↑14||Martinez, Josep M., Carme Comas, Julia Ojuel, Antoni Borrell, Bienvenido Puerto, and Albert Fortuny. “Fetal heart rate patterns in pregnancies with chromosomal disorders or subsequent fetal loss.” Obstetrics & Gynecology 87, no. 1 (1996): 118-121.|
|↑15||Folic Acid Supplementation. The American Journal of Clinical Nutrition.|
|↑16||May, Linda E., Alan Glaros, Hung-Wen Yeh, James F. Clapp, and Kathleen M. Gustafson. “Aerobic exercise during pregnancy influences fetal cardiac autonomic control of heart rate and heart rate variability.” Early human development 86, no. 4 (2010): 213-217.|
|↑17||May, Linda E., Susan A. Scholtz, Richard Suminski, and Kathleen M. Gustafson. “Aerobic exercise during pregnancy influences infant heart rate variability at one month of age.” Early human development 90, no. 1 (2014): 33-38.|
|↑18||Manders, M. A. M., G. J. B. Sonder, E. J. H. Mulder, and G. H. A. Visser. “The effects of maternal exercise on fetal heart rate and movement patterns.” Early human development 48, no. 3 (1997): 237-247.|
|↑19||Nanal, Vaidya RM. “Food in pregnancy an Ayurvedic overview.” Ancient science of life 28, no. 1 (2008): 30.|
|↑20||Malik, Sadia, Mario A. Cleves, Margaret A. Honein, Paul A. Romitti, Lorenzo D. Botto, Shengping Yang, and Charlotte A. Hobbs. “Maternal smoking and congenital heart defects.” Pediatrics 121, no. 4 (2008): e810-e816.|
|↑21||Meyer‐Wittkopf, M., J. M. Simpson, and G. K. Sharland. “Incidence of congenital heart defects in fetuses of diabetic mothers: a retrospective study of 326 cases.” Ultrasound in Obstetrics & Gynecology 8, no. 1 (1996): 8-10.|
|↑22||Carnegie Stages. Embryology.|
|↑23||Prenatal Form and Function.The Endowment for Human Development.|
|↑24||Heartbeat Calculator.The Endowment For Human Development.|
|↑25||Prenatal Form and Function. The Endowment For Human Development.|