Ever wonder when your baby’s heart starts to beat? You might not feel those little kicks and flutters until later, but your baby’s been busy growing from the very beginning. From the moment of conception, there’s a whole world of development happening—starting with a single cell, turning into a flickering heartbeat, and eventually becoming the sweet face you’ll soon snuggle.
Let’s walk through the week-by-week magic of fetal development, from one mama to another— with insights from our experts: Dr. Kecia Gaither, a double board-certified OB/GYN and maternal-fetal medicine specialist who focuses on high-risk pregnancies and fetal health, and Dr. Pragati Kakkar, an IVF specialist and OB-GYN at United Wellness, with a deep focus on reproductive medicine and prenatal care.
When does a baby have a heartbeat?
The earliest heartbeat typically appears around week 6 of pregnancy, just a week or so after your missed period. At this stage, the baby is still an embryo, but that tiny flicker you see on an ultrasound? That’s their heart beginning to beat for the first time.
When can you hear a baby’s heartbeat?
You may not hear your baby’s heartbeat right away—even if it’s already fluttering to life. According to Dr. Kecia Gaither, a double board-certified OB/GYN and maternal-fetal medicine specialist, most providers rely on a transvaginal ultrasound around week 6 or 7 to detect the heartbeat for the first time.
“In high-risk pregnancies, we typically confirm the fetal heartbeat every one to two weeks during the first trimester,” says Dr. Gaither. Around week 10 to 12, a handheld Doppler device may pick it up more easily, especially in low-risk pregnancies.
What’s the normal fetal heart rate for a baby?
A healthy fetal heart rate typically ranges between 110 and 160 beats per minute (BPM), though it can fluctuate based on your baby’s activity level and stage of development.
Dr. Pragati Kakkar explains that while some variation in fetal heart rate is normal, extreme readings can be a red flag. “A fetal heart rate below 100 BPM after 6–7 weeks can be a warning sign of possible miscarriage or poor fetal development,” she notes.
On the flip side, if the heart rate consistently climbs above 180 BPM during the first trimester, it might signal a concern.
“A higher-than-normal heart rate could indicate fetal distress or another issue,” Dr. Kakkar adds. However, she reassures that “short bursts or accelerations—especially with fetal movement—can still be perfectly normal.”
This is why regular prenatal checkups and heartbeat monitoring are so important.
What can an anatomy scan tell us about the health of the heart and organs?
Between 18 and 22 weeks pregnant, your provider will likely schedule a detailed anatomy scan—one of the most exciting (and important) ultrasounds during pregnancy. This mid-pregnancy scan checks in on how your baby is growing and developing from head to toe.
“ “The anatomy scan offers a comprehensive look at the baby’s heart, brain, spine, limbs, and internal organs. “It allows us to assess growth, structure, and function all in one appointment.
One of the most important parts of the scan is its ability to catch congenital conditions early. According to Dr. Kakkar, “We can detect heart defects like ventricular septal defects or hypoplastic left heart syndrome, and issues with the brain, spine, kidneys, or abdominal wall.” Spotting these signs early makes a big difference—it helps parents connect with pediatric specialists and plan for any interventions, if needed.
Alongside organ development, the scan also checks amniotic fluid levels, placenta placement, and the umbilical cord’s insertion point—three key factors that support healthy fetal development throughout the rest of your pregnancy.
Did you know?
By week 8, your baby’s heart beats almost twice as fast as yours!
Why you might not hear the baby’s heartbeat
Don’t panic if the heartbeat isn’t detectable early on. It could simply be:
- Too early in pregnancy
- Baby’s position
- High maternal BMI
- Equipment sensitivity
Your healthcare provider will guide you through what’s normal for your timeline.
The week-by-week timeline of your baby’s heart development
Weeks 1-4: The beginning of it all
Conception marks the start. Once the sperm meets the egg, a zygote forms and becomes a blastocyst, nestling into your uterine lining. Around week 4, it officially becomes an embryo.
“Successful implantation is confirmed with a rising serum beta-hCG level and a transvaginal ultrasound showing a gestational sac and embryo in the uterus,” Dr. Gaither explains. She adds that in high-risk pregnancies, providers typically use ultrasound to assess the fetal heartbeat starting around 6 weeks, then monitor it every 1–2 weeks during the first trimester to ensure healthy development.
Did you know?
Your baby’s sex is determined at conception—even if you won’t find out for weeks!
Weeks 5-8: The embryo takes shape
The neural tube, which becomes the brain and spine, forms. This is also when a baby has a heartbeat for the first time, around week 6. Limbs bud, organs begin to take shape, and your embryo is now about the size of a raspberry.
Did you know?
What devices are used to hear the baby’s heartbeat? Transvaginal ultrasound (as early as week 6) Doppler fetal monitor (around week 10–12) Fetoscope or stethoscope (after week 20)
Weeks 9-12: Hello, fetus!
At week 9, your baby graduates from embryo to fetus—a significant milestone in those early weeks of development. Their tiny facial features are taking shape, and those itty-bitty fingers, toenails, and even tooth buds are beginning to form.
By week 12, all of your baby’s major organs are in place, and the heartbeat is stronger and easier to detect with a Doppler. This is also when your baby starts showing off new skills—like stretching, yawning, and maybe even a little hiccup or two!
Did you know?
Your baby can yawn and hiccup by week 12!
Weeks 13-18: Movement and milestones
You might start to feel those first flutters—aka quickening—around week 18. It can feel like bubbles or soft taps, and it’s often the first time you really start to feel connected to your baby. By now, the fetus can hear sounds and even respond to light. Bones are hardening, and fingerprints are forming, giving your baby their own unique identity.
During this period, your baby’s heart continues to mature. By week 13, the heart rate typically decreases from its earlier peak to a range of 110–160 beats per minute, maintaining a rhythm faster than an adult’s heart rate. This adjustment supports the growing fetus’s metabolic needs and is a normal part of development.
Week 19-24: From wiggles to kicks
Skin is still translucent, but fat is forming, and the lungs are growing fast. By week 20, the anatomy scan gives a full view of baby’s development, including the heart.
“ The scan for anatomy is done between 18–22 weeks of pregnancy, and it provides a detailed evaluation of the baby’s organs, heart, brain, spine, face, limbs, and overall growth,”
She explains, “The scan helps diagnose major congenital abnormalities, eg, heart defects (like ventricular septal defects or hypoplastic heart syndrome), brain and spine problems (like spina bifida), kidney problems (like absent or cystic kidneys), and abdominal wall defects.”
Dr. Kakkar adds, “The scan also assesses the amniotic fluid, placenta location, and umbilical cord insertion to ensure healthy fetal development. Early identification of these can help referrals to specialists and offer early intervention.”
Did you know?
Your baby now has sleep-wake cycles, kind of like a newborn!
Weeks 25-32: Practicing for life outside
To support your baby’s brain and heart development, Dr. Gaither recommends starting with the basics.
“ A balanced diet and consistent prenatal care can go a long way in shaping healthy outcomes for your baby The earlier these habits are adopted, the better the chances of supporting critical organ development—especially the heart and brain, which begin forming in the first few weeks.”
Key steps she advises: take prenatal vitamins (mainly folic acid), avoid alcohol, tobacco, and drugs, manage conditions like diabetes or high blood pressure, and keep up with prenatal visits.
Did you know?
Baby may respond to your voice with increased movement or a faster heart rate.
Weeks 33-40: Almost there!
Now gaining about half a pound per week, your baby’s organs are ready. By week 37, your little one is considered full-term and preparing for birth. “Fetal heart rate patterns assess adequate oxygenation, reflecting variability, and a normal rate. Abnormal rates, loss of variability may be indicative of fetal distress and the subsequent need for intervention with delivery,” says Dr. Gaither.
Conclusion
And just like that, your baby goes from a barely-there bundle of cells to a heartbeat you’ll never forget—and soon, a little person you’ll get to hold in your arms. It’s pretty wild (and wonderful). How much happens in just 40 weeks? From that first flicker of a heartbeat around week 6 to the steady rhythm guiding delivery, every beat tells a story of growth, strength, and life.
No matter where you are in your pregnancy—just found out, 18 weeks and pregnant, or counting down the days—knowing what’s happening inside can help you feel more connected to your baby. You’ve got this, mama.
FAQs
Q: Can I hear my baby's heartbeat at home?
A: Yes, with a home Doppler device—but always check with your OB-GYN first.
Q: Can you hear baby’s heartbeat with the human ear?
A: Not quite! Baby’s heartbeat is too soft and deep within the womb to be heard unaided. But technology gives us a front-row seat to these tiny thumps.
Q: What if the heartbeat can’t be found during an early scan?<br>
A: It might just be too early. Your doctor may suggest rechecking in a week or two.
Q: Is a faster heartbeat a sign of a boy or girl?
A: The “heartbeat gender” myth is fun, but not supported by science. Only a genetic test or ultrasound can tell!
Q: What happens if the heartbeat slows down or changes?<br>
A: Your healthcare provider will monitor patterns and may recommend further testing to rule out concerns.
Q: How can I keep track of fetal development week by week?
A: Use pregnancy tracking apps or look for weekly pregnancy updates from trusted sources to stay informed.
