Does a Baby in the Womb Open Its Mouth? A Complete Guide for Expecting Parents
Pregnancy is a journey filled with curiosity. Whether it’s the first kick, the baby’s heart rate, or how the little one moves inside the womb—every mother wants to know what her baby is doing throughout those magical nine months. One very common question many pregnant women ask during their routine scans at Nisarga Diagnostics Bangalore is:
“Does my baby open its mouth inside the womb?”
And the answer is—Yes! Babies do open and close their mouth while still inside the mother’s womb. They even yawn, swallow, practice breathing, and occasionally make adorable facial expressions.
This blog explains in detail why babies open their mouths inside the womb, what it means for your baby’s development.
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Do Babies Really Open Their Mouth in the Womb?
Yes. From around 11–12 weeks of pregnancy, a developing fetus begins to perform tiny mouth movements. These movements aren’t random—they are a part of crucial developmental milestones.
What Babies Do with Their Mouth Inside the Womb
- ✔️ Open and close their mouth
- ✔️ Swallow amniotic fluid
- ✔️ Practice breathing movements
- ✔️ Yawn
- ✔️ Occasionally stick out the tongue (yes, it’s true!)
- ✔️ Form sucking motions
- ✔️ Practice facial expressions
These actions are normal, healthy, and essential for the baby’s growth.
Why Does a Baby Open Its Mouth Inside the Womb?
(A) Swallowing Amniotic Fluid
Swallowing is one of the earliest skills a baby learns.
The amniotic fluid they swallow:
- Helps develop the digestive system
- Helps in lung development
- Maintains the right amount of amniotic fluid in the womb
Doctors at Nisarga Diagnostics often observe swallowing movements during fetal growth scans.
(B) Yawning – A Sign of Brain and Neural Development
Ultrasound studies show that fetal yawning begins around 14–16 weeks. Although the exact purpose is still being researched, yawning is believed to support:
- Brain growth
- Nervous system maturity
- Jaw muscle strengthening
So if you see a cute yawn during your anomaly scan at Nisarga Diagnostics Bangalore, it’s completely normal—and adorable!
(C) Oral Muscle Practice for Feeding After Birth
Before birth, a baby cannot suck milk or breathe air. But the baby practices sucking and swallowing inside the womb to prepare for feeding after birth.
The baby practices:
- Sucking movements
- Chewing-like motions
- Tongue movement
- Lip movement
These skills allow the baby to breastfeed or bottle-feed effectively after delivery.
(d)Practicing Breathing Movements
While babies do not breathe air inside the womb, they do practice breath-like movements.
This includes:
- Opening the mouth
- Moving the diaphragm
- Expanding and contracting the chest
These movements help in:
- Lung growth
- Strengthening breathing muscles
- Preparing for first breath after birth
At Nisarga Diagnostics, breathing movements are often checked during biophysical profile (BPP) scans.
When Do Mouth Movements Begin in the Womb?
Week-wise Development Timeline
✔️ 8–10 Weeks
Jaw begins to form but mouth movement isn’t visible yet.
✔️ 11–12 Weeks
First mouth opening and closing movements start.
✔️ 14–16 Weeks
Baby may start yawning; swallowing becomes more coordinated.
✔️ 20 Weeks
Sucking and tongue movements improve; visible in anomaly scan.
✔️ 28 Weeks Onward
Baby practices breathing and swallowing regularly.
Pregnancy scans at Nisarga Diagnostics clearly capture these movements, especially during detailed anomaly scans or growth scans.
What Do Ultrasound Scans Show About Baby’s Mouth?
During a scan, especially at a trusted center like Nisarga Diagnostics, sonologists look for several mouth-related developmental features.
(A) Baby Opening and Closing Mouth
This is often seen during 2D and sometimes 3D scans.
It is a normal part of development.
(B) Fetal Swallowing
Doctors ensure the baby is swallowing amniotic fluid properly.
This indirectly confirms:
- Healthy digestive system
- Healthy nervous system
- Good fetal well-being
(C) Tongue Movement
Sometimes, the baby might be seen sticking out its tongue or moving it inside the mouth.
(D) Yawning
One of the most beautiful moments during a scan!
Yawning is harmless and common.
(E) Lip and Jaw Movements
Most noticeable at around 28–32 weeks, especially if you opt for a 3D/4D pregnancy scan at Nisarga Diagnostics Bangalore.
All these movements are part of fetal activity and are monitored to ensure normal brain and muscle development
Is It Normal If the Baby Does NOT Open Its Mouth During a Scan?
Absolutely yes.
Babies sleep in 20- to 40-minute cycles inside the womb.
During this sleep time:
- They may not move
- They may keep the mouth closed
- They may not swallow or yawn
Just because you didn’t see it during the 10–15 minutes of scanning doesn’t mean your baby isn’t doing it throughout the day.
At Nisarga Diagnostics, sonologists may gently nudge the baby’s position or wait a few minutes if detailed views are needed.
How Pregnancy Scans Help Confirm Baby’s Oral & Facial Development
A fetal mouth is more than just a tiny opening—it also indicates:
- Jaw development
- Lip formation
- Tongue structure
- Face symmetry
What Each Scan Shows
✔ NT Scan (11–14 weeks)
- Early facial structure
- Jaw and chin outline
- Tongue position
- Screening for genetic conditions
✔ Anomaly Scan (18–20 weeks)
- Cleft lip or palate detection
- Jaw bone development
- Baby’s mouth opening/closing
- Tongue movements
- Swallowing movements
This is one of the most crucial pregnancy scans at Nisarga Diagnostics Bangalore.
✔ Growth Scan (28–32 weeks)
- Baby’s swallowing
- Breathing practice
- Mouth and lip movements
- Head and neck positioning
These scans help ensure healthy fetal neurological development.
What If Baby Swallows Too Much or Too Little Amniotic Fluid?
Your doctor evaluates this by checking:
- Amniotic Fluid Index (AFI)
- Mouth movements
- Swallowing actions
- Stomach fill
- Fetal breathing movements
Too Much Amniotic Fluid (Polyhydramnios)
Sometimes, excess fluid can indicate:
- Baby not swallowing enough
- Rare digestive issues
- Maternal diabetes
Too Little Amniotic Fluid (Oligohydramnios)
May indicate:
- Decreased fetal urine output
- Placental issues
- Maternal dehydration
Doctors at Nisarga Diagnostics will guide you based on your AFI levels and scan findings.
Can Baby Breathe Through the Mouth Inside the Womb?
No.
Inside the womb:
- Baby does not breathe air
- Lungs are filled with amniotic fluid
- Oxygen is provided through the placenta and umbilical cord
Mouth opening is not for breathing—it is for:
- Swallowing
- Practicing muscle movements
- Reflex development
The first breath happens only after birth.
Fun Facts About Baby Movements Inside the Womb
Here are some heart-melting facts most parents love:
✨ Babies practice smiling as early as 20 weeks.
Though these are reflexes, they’re adorable to see during 3D scans.
✨ Babies taste flavors from the amniotic fluid.
If the mother eats garlic or something sweet, the baby can sense it.
✨ Baby hiccups begin around 10–12 weeks.
These cause rhythmic jumps felt during pregnancy.
✨ Babies can respond to sound from 24–26 weeks.
Some even open their mouth as a response!
Pregnancy scans at Nisarga Diagnostics Bangalore often capture these beautiful moments.
Why Choose Nisarga Diagnostics for Pregnancy Scans?
When it comes to tracking fetal movements, facial development, and overall fetal well-being, having the right diagnostic center is essential.
Why Parents Trust Nisarga Diagnostics
- ✔ Highly experienced fetal medicine specialists
- ✔ Advanced 2D, 3D, and 4D ultrasound machines
- ✔ Accurate anomaly and NT scans
- ✔ Detailed fetal growth monitoring
- ✔ Comfortable environment for expecting mothers
- ✔ Reports explained clearly in simple language
- ✔ Trusted pregnancy scan center in Bangalore
Whether it is to watch your baby open their mouth, yawn, or simply move, Nisarga Diagnostics ensures a safe, detailed, and comforting experience.
Final Takeaway: Mouth Movements Are a Healthy Sign
Let’s summarize:
Yes, babies open their mouth in the womb
They also yawn, swallow, practice breathing, and make sucking motions
These movements are normal, healthy, and necessary for development
Pregnancy scans at Nisarga Diagnostics Bangalore can show these adorable movements clearly
It is perfectly fine even if you don’t see it during one particular scan
Every baby grows at their own pace, and these movements are part of their tiny preparation for life outside the womb.
If You Are Pregnant in Bangalore…
Make sure you get your scans done at a reliable center.
For clear imaging, expert interpretation, and warm care, Nisarga Diagnostics provides some of the best pregnancy scans in Bangalore.
Founder of Nisarga Diagnostics, is a renowned fetal ultrasound specialist with over 20 years of expertise. An alumnus of Government Medical Colleges in Mysore and Bangalore, he also holds a D.N.B. from the National Board of Examinations, Delhi, and certification from the Fetal Medicine Foundation, London. A former Professor and HOD, he has trained countless PG students and junior radiologists, shaping the future of fetal imaging in India.