CircleBumpCheckedFilledMedicalBookmarkBookmarkTickBookmarkAddCheckBoxCheckBoxFilled

When Does a Baby Have a Heartbeat?

Hearing baby’s heartbeat for the first time is an exciting pregnancy milestone—here’s what you can expect.
save article
profile picture of Sarah Bradley
Published July 31, 2024
pregnant couple listening to baby's heartbeat with doppler device
Image: ByLorena | Stocksy United

Hearing baby’s heartbeat for the first time is one of the most exciting new-mom milestones. If you’re preparing for your first pregnancy ultrasound, you might be wondering: When does a baby have a heartbeat? Here’s what to know about how baby’s heart develops during pregnancy and when you’ll be able to hear the fetal heartbeat.

When Does a Baby Have a Heartbeat?

According to the Journal of Prenatal Medicine, the heart begins forming between weeks 3 and 4 of gestation, and starts beating more regularly around week 5. By week 6, the fetal heartbeat is consistent at around 105 beats per minute (bpm), says March of Dimes.

When Can Baby’s Heartbeat Be Detected by Ultrasound?

A baby heartbeat can be seen on an ultrasound pretty early in pregnancy, although it can depend on the type of ultrasound being performed. A vaginal ultrasound is more accurate in the first few weeks, and can often detect a fetal heartbeat around 6 weeks gestation, while an abdominal ultrasound can usually pick it up by 7 weeks, says the American Pregnancy Association (APA).

What if your provider can’t detect a fetal heartbeat?

There are many reasons your provider might not be able to detect a baby heartbeat through ultrasound at the beginning of pregnancy. Some of them point to a potential problem with your pregnancy, but often there’s not any cause for concern.

Mary Margaret McGue, MD, an ob-gyn at Summit Health in New Jersey, says it’s common to incorrectly calculate baby’s gestational age when you first find out you’re pregnant, which may mean you’re looking for a heartbeat on an ultrasound sooner than it’s possible to see one. “We base gestational age off of your last menstrual period (LMP) with the assumption that the typical woman ovulates about 14 days after the onset of their LMP,” she explains, “[but] not every woman’s body ovulates on this time schedule.”

Related Video

This normal variation in ovulation timing is one reason why your provider might schedule you for a dating ultrasound, which McGue says is the best tool for accurately establishing how far along you are: This ultrasound looks for the gestational sac and yolk sac and, if possible, takes crown-to-rump measurements of baby, all of which help your provider figure out your gestational age. If a fetal heartbeat isn’t detected yet, it may simply be because you’re earlier in your pregnancy than you initially thought; if that’s the case, McGue says you’ll likely be scheduled to have another ultrasound in two weeks to look again.

Your body size can potentially play a part too. If you’re overweight or obese, McGue says it could be harder to detect a baby heartbeat without a transvaginal ultrasound, so a provider using only a small handheld device may not be able to pick it up.

There’s also a possibility that not finding a fetal heartbeat means you’ve experienced a miscarriage. Miscarriages are unfortunately common, affecting 10 to 20 percent of pregnancies, according to research. If you need help coping with the difficulty of a miscarriage, it’s important to reach out to a mental health provider.

When Can You Hear Fetal Heartbeat by Doppler?

It’s harder to find a fetal heartbeat on a handheld doppler device than on an ultrasound. Michael Tahery, MD, an ob-gyn and urogynecologist practicing in Los Angeles, says providers can usually detect the heartbeat with a doppler between 10 and 12 weeks gestation.

That’s one reason why women typically have a prenatal visit scheduled during those weeks: It might be the first time you hear baby’s heartbeat (unless you’ve had a dating ultrasound earlier).

Is There an Average Heartbeat Rate for a Fetus?

The average heartbeat of a fetus in the first trimester is around 180 bpm, says G. Thomas Ruiz, MD, lead ob-gyn at MemorialCare Orange Coast Medical Center in Fountain Valley, California. It can be anywhere from 120 to 160 bpm in the second and third trimester.

Fetal heartbeat by week

Baby’s heart rate fluctuates throughout pregnancy, beating its fastest in the first trimester, then gradually slowing down as your pregnancy continues. On average, according to research, baby’s heart will beat at:

  • 110 bpm at 6 weeks
  • 170 bpm at 9 to 10 weeks
  • 150 bpm at 14 weeks
  • 140 bpm at 20 weeks
  • 130 at 40 weeks

Does baby heartbeat indicate gender?

Unfortunately, you can’t skip the line and find out baby’s sex by knowing the fetal heartbeat. “Some people believe that a heart rate less than 140 bpm indicates a male and more than 140 bpm indicates a female, but this isn’t reliable,” says Ruiz, adding that “heartbeat variability is considered a sign of a healthy fetus.”

How Does the Fetal Heart System Develop and Work?

What eventually becomes a four-chamber heart starts as pulsating tissue inside the developing embryo, says Ruiz. This is what you might be able to see on an ultrasound at 6 weeks gestation. By 8 weeks, that pulsating tissue has turned into the primary vessels and structures of the heart, says Tahery, although some other vessels won’t develop until the second trimester. By 18 to 22 weeks gestation, baby’s heart is basically formed and functioning the way it’s supposed to—that’s why you’ll be scheduled for an anatomy scan around this time.

During pregnancy, baby’s heart is continually sending blood to the lungs to collect oxygen and then distributing that oxygenated blood to the rest of the cells in the body, says Tahery. Before baby’s born, their lungs aren’t mature enough to oxygenate blood yet, so the placenta does that work instead, he adds.

Bottom line: The fetal heart develops long before you even realize you’re pregnant (at around 3 weeks gestation) and by the middle of the second trimester, it’s already doing basically everything it will ever need to do: pumping blood through the body to supply baby’s cells with oxygen. Because the heart forms and starts working so quickly, baby typically has a heartbeat at around 5 weeks gestation. You can usually detect the heartbeat by ultrasound at 6 to 7 weeks and by doppler at 10 to 12 weeks.

Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.

Sources

Mary Margaret McGue, MD, is an ob-gyn at Summit Health in New Jersey. She received her medical degree from Rutgers New Jersey Medical School.

G. Thomas Ruiz, MD, is the lead ob-gyn at MemorialCare Orange Coast Medical Center in Fountain Valley, California. He received his medical degree from University of California Irvine School of Medicine.

Michael Tahery, MD, is an ob-gyn and urogynecologist practicing in Los Angeles. He received his medical degree from the University of California Irvine.

Journal of Prenatal Medicine, Fetal Cardiac Function During the First Trimester of Pregnancy, 2011

March of Dimes, Pregnancy Week by Week: Week 6

American Pregnancy Association, Early Fetal Development

European Journal of Radiology, Gestational Sac, 2017

StatPearls, Early Pregnancy Loss (Spontaneous Abortion)

BMJ Journals, Rhythm Abnormalities of the Fetus, September 2007

Learn how we ensure the accuracy of our content through our editorial and medical review process.

save article
ADVERTISEMENT

Next on Your Reading List

mother giving newborn baby a bottle while sitting on hospital bed after labor and delivery
Fetal Viability: When Can Baby Survive Outside the Womb?
Medically Reviewed by Kendra Segura, MD
pregnant woman looking at ultrasound photo of baby in womb
How Do Babies Breathe in the Womb?
Medically Reviewed by Kendra Segura, MD
close up of weedkiller being sprayed
EPA Bans Weedkiller Proven Harmful to Developing Fetuses
By Wyndi Kappes
ADVERTISEMENT
husband kissing wife's pregnant belly while sitting on couch at home
The Benefits of Talking to Baby in Utero
Medically Reviewed by Lauren Crosby, MD
pregnant woman and husband reading book to baby in womb
7 Ways to Make Baby Smarter Before Birth
Medically Reviewed by Dina DiMaggio Walters, MD
close up of pregnant woman holding ultrasound picture
What to Know About Fetal Development in the Third Trimester
By Nehal Aggarwal
close up of woman's pregnant belly in the sunlight at home
Is It Safe to Smoke Marijuana While Pregnant?
Medically Reviewed by Kendra Segura, MD
ADVERTISEMENT
pregnant woman eating a salad at home
Dad’s Genes Are the Reason for Unborn Baby’s Insatiable Appetite
By Wyndi Kappes
pregnant woman looking at pregnancy trimester calendar
Stages of Pregnancy: When Does Each Trimester Start and End?
Medically Reviewed by Kendra Segura, MD
overhead view of pregnant woman sitting on bed holding belly
This Is How Hard Your Baby Is Kicking, According to Science
Medically Reviewed by Kendra Segura, MD
ADVERTISEMENT
pregnant woman looking at ultrasound photo of baby
Watch How Your Organs Make Room for Baby
Medically Reviewed by Kendra Segura, MD
family about to pop their gender reveal balloon
It’s Not 50-50: Why Your Chances of Having a Boy Are Slightly Higher
Medically Reviewed by Kendra Segura, MD
close up of pregnant woman wearing a floral dress outside in the summertime
How Super Antibodies From Mom Protect Baby and May Help Treat Disease
By Wyndi Kappes
ADVERTISEMENT
close up of pregnant woman talking to her doctor about ultrasound results
What to Know About Congenital Heart Disease in Babies
By Elizabeth Narins
Cannabis Use During Pregnancy May Affect Child Development, Study Says
Cannabis Use During Pregnancy May Affect Child Development, Study Says
By Nehal Aggarwal
mother in hospital after just giving birth newborn
What Does the Placenta Do?
By Korin Miller
pregnant woman looking at her sonogram
This Common Pregnancy Condition Could Up Baby’s Risk of Autism or ADHD
By Ashley Edwards Walker
ADVERTISEMENT
sonogram machine at doctor's office
Mom-to-Be’s Hilarious ‘Demon’ Baby Sonogram Goes Viral
By Laurie Ulster
smiling pregnant woman in urban setting
This Is How Mom’s and Baby’s Cells Communicate During Pregnancy
By Stephanie Grassullo
pregnant woman holding her sonogram
Study: Industrial Chemicals Pass From Mother to Fetus Throughout Pregnancy
By Stephanie Grassullo
ADVERTISEMENT
Article removed.
Article removed.
Name added. View Your List