When Does a Fetus Have a Heartbeat?

Shenan J. Boquet
May 2, 2023
Reproduced with Permission
Human Life International

Throughout a woman's pregnancy, her baby undergoes many stages of development before birth. Among the milestones that indicate life is the heartbeat. But when does a fetus have a heartbeat?

What to Know about Fetal Heartbeat Development

Through the use of ultrasounds, modern science can detect the waves of the baby's heartbeat as early as three weeks after fertilization. Although the child's organs have not yet fully formed, soon after this three-week mark the heart beats about 110 times per minute.

A fetal heartbeat can be distinguished from the mother's because it is often much faster than hers. Listen here to experience firsthand how the fetal heartbeat develops throughout a woman's pregnancy.

The Developing Heart and Heartbeat

According to Lumen Learning, the heart of a preborn baby:

"...originates about day 18 or 19 from the mesoderm and begins beating and pumping blood about day 21 or 22. It forms from the cardiogenic region near the head and is visible as a prominent heart bulge on the surface of the embryo.... The primitive heart begins to form an S shape within the pericardium between days 23 and 28. The internal septa begin to form about day 28, separating the heart into the atria and ventricles, although the foramen ovale persists until shortly after birth. Between weeks five and eight, the atrioventricular valves form. The semilunar valves form between weeks five and nine."

This miraculous growth proves the existence of a human being who is not a part of his mother but who is his own person and reliant upon her for sustenance.

Once the heart begins its detectable beat, it is obvious that it beats much faster than an adult's. What to Expect's article for expectant mothers explains the varying speeds at which the baby's heart beats. By six weeks, the heart is beating 110 times a minute. Just two weeks later, it will rise to between 150 and 170 times a minute.

By weeks nine or 10, the baby's heart will beat about 170 times per minute. At this point, it begins to slow down. Then around week 20, it'll go to about 140 beats per minute.

During labor, the baby's heart rate can go anywhere from 110 to 160 beats per minute, with normal variations on either side.

How Does a Doctor Detect a Baby's Heartbeat?

According to Johns Hopkins, there are two kinds of fetal heart monitoring: external and internal.

When a doctor listens externally, one of the tools he uses is called a Doppler ultrasound device. This method listens to a baby's heartbeat through the mother's belly. A doctor will listen during routine prenatal visits and if he suspects something is wrong. In addition, when a woman is in labor, the baby's heart rate will also be monitored continuously using what's called a transducer--or ultrasound probe--that's fastened to the woman's belly. This helps the doctors determine if the baby is experiencing any distress.

If the doctor is concerned about the baby's well-being during labor, he can monitor the baby's heart rate by placing an electrode directly on the baby's scalp. The Johns Hopkins article states that this electrode is connected to a monitor and "gives better readings because things like movement don't affect it. But it can only be done if the fluid-filled sac that surrounds the baby during pregnancy (amniotic sac) has broken and the cervix is opened. Your provider may use internal monitoring when external monitoring is not giving a good reading. Or your provider may use this method to watch your baby more closely during labor."

Obviously, this step is only taken if the doctors have a grave concern about the baby's condition.

Is It Really a Heartbeat?

Some abortionists, such as Nisha Verma, state that the baby's heartbeat isn't actually a "real" heartbeat because the valves that open and close to create the sound of a heartbeat don't form until the 9th or 10th week. Verma states that in a younger baby, "the flickering that we're seeing on the ultrasound that early in the development of the pregnancy is actually electrical activity."

Further, mainstream media has jumped on the heartbeat bandwagon, claiming that the sound of a heartbeat is manufactured. In an article from NBC, the author paraphrases from and then quotes Verma, saying, "'In fact, the sound pregnant people hear during ultrasounds at six weeks is entirely manufactured by the ultrasound machine,' Verma said. 'It's an electrical pulse that's translated into the sound we're hearing from the ultrasound machine.'"

It's important to understand what an ultrasound does. According to Johns Hopkins:

Ultrasound uses an electronic wand called a transducer to send and receive sound waves. ... The transducer is moved over the abdomen, and sound waves move through the skin, muscle, bone, and fluids at different speeds. The sound waves bounce off the baby like an echo and return to the transducer. The transducer converts the sound waves into an electronic image on a computer screen.

The ultrasound uses sound waves to create an image. And one of the things that the ultrasound detects is the baby's heartbeat. If you have ever seen a baby in an ultrasound, you will know that, in addition to hearing the heartbeat, you can also see the heart pulse. So, while the ultrasound translates the movement into sound waves, that doesn't mean the sound is created out of nothing. It's created based on movement - in this case, the beating of the heart.

In addition, we see that as far back as 1992, researchers examined fetal heartbeat and found that "cardiac activity is present in normal embryos before it can be detected on ultrasound," which means the heart is beating long before we can hear it.

Throughout pregnancy, a baby is growing and developing at a phenomenal rate. This growth and development could only happen in a living being.

And, as we can hear in , a baby's heart is beating regardless of the heart's this videostage of development. The heart simply hasn't developed to its final stage. But that doesn't mean the baby is not alive. On the contrary, the baby grows exponentially every day!

The facts are irrefutable. A baby is created at fertilization - the beginning of life. The formation of the human heart, manifested by its heartbeat, is a clear indicator that another human being is present in the mother's womb. This fact is what the heartbeat bills are attempting to teach and protect. They're not stating that human life beings at the first detection of the heartbeat. Rather, they are stating that the discovery of the heartbeat shows that life is already present.

Heartbeat Bills

Several states have enacted laws to protect some babies after a heartbeat is detected. Other states have enacted laws to protect some babies, such as those diagnosed with Down syndrome or babies after 20 weeks' gestation.

Despite this effort, these laws are still flawed, because they do not protect all babies or in all circumstances. We know that a good pro-life law must protect all babies, as the Catechism of the Catholic Church emphatically teaches an abortion is never permissible (2271).

Abortion and Two Questions about Life

The debate on whether abortion is an acceptable medical procedure essentially comes down to two questions:

  1. When does human life begin?
  2. Is it permissible to kill an innocent life?

Science answers the first. A human being begins life at the moment of fertilization, and what follows after that is simply a developing human being, not just "fetal tissue," a "clump of cells," or "potential life," as some pro-abortion activists and doctors say. Life begins at conception and carries through until natural death.

The decision of the Supreme Court in Roe v. Wade doesn't define where life begins but indicates that we can tell that there is life inside the womb once the child has "viability" (i.e., the child is able to live outside of the womb). There are many problems, however, with stating life begins with viability, including that even the date of viability is not a hard line: preemies are being delivered earlier and earlier and surviving.

Now that we have established that a human being is created at fertilization, natural law answers the second question. It is neither right nor just to kill an innocent person--and this is something people fundamentally understand.




A human being's life begins at fertilization, and from there the child begins to develop. Abortion is never the answer, as it takes away the life of an innocent person. Detecting a child's heartbeat is significant proof that a separate human being is present and growing in the womb.

Heartbeat bills attempt to reduce the number of abortions in the US and call to people's minds important questions considering life and the family. Further, they help our society move one more step toward understanding the humanity of the preborn baby.

Hopefully soon, people will understand the humanity of the baby and they will want to protect it. And then we will live in a country that can answer the question Does one really have a right to take away another's life? with an emphatic "no."