What Does a Fetus Look Like? Complete Visual Development Guide

Curious about your baby's appearance throughout pregnancy? This comprehensive visual guide describes what your fetus looks like from early development through full term. From the first recognizable features to the fully formed newborn, discover the incredible transformation your baby undergoes in the womb.

Early Development: What Your Baby Looks Like at 4-8 Weeks

During the earliest stages of pregnancy, your baby transforms from a cluster of cells to a recognizable embryo with basic human features. This period sees the most dramatic changes in appearance.

Week 4: The Beginning

Size: 2-4mm (smaller than a peppercorn)
Overall appearance: Curved, elongated structure

What You'd See:

  • Shape: C-shaped curve with a visible tail
  • Head region: Disproportionately large compared to body
  • Body: Simple tube-like structure
  • Features: Dark spots where eyes will form
  • Limbs: Tiny limb buds just beginning to appear
  • Transparency: Semi-transparent, internal structures visible

Key Visual Features:

Your baby looks like a tiny seahorse with a large head region and curved body. The most prominent feature is the developing brain area, which appears as a large bulge. A small tail is clearly visible, and tiny bumps indicate where arms and legs will develop.

Week 5: Taking Shape

Size: 4-6mm (size of sesame seed)
Overall appearance: More defined head and body regions

What You'd See:

  • Head: Even more prominent, about half the total length
  • Facial area: Dark indentations for future eyes
  • Body: More cylindrical shape emerging
  • Heart: Visible bulge where heart is developing
  • Limb buds: More pronounced arm and leg buds
  • Tail: Still prominent but relatively smaller

Key Visual Features:

The head continues to dominate, but the body is becoming more defined. You might notice a rhythmic pulsing in the chest area - this is the developing heart beginning to beat. The limb buds look like small paddles extending from the body.

Week 6: Recognizable Form

Size: 8-12mm (size of lentil)
Overall appearance: Distinctly human-like form beginning to emerge

What You'd See:

  • Head: Large and rounded with visible brain development
  • Eyes: Dark spots more clearly defined
  • Mouth area: Small depression where mouth will form
  • Limbs: Arm and leg buds clearly visible
  • Body: Beginning to straighten and elongate
  • Tail: Starting to appear smaller relative to body

Key Visual Features:

Your baby is beginning to look less like a fish and more like a tiny human. The head is still very large, but facial features are starting to appear as small indentations. The limb buds are more paddle-like and you can distinguish between arms and legs.

Week 7: Facial Features Emerge

Size: 12-16mm (size of blueberry)
Overall appearance: More human-like with developing facial features

What You'd See:

  • Eyes: Dark pigmented areas, still on sides of head
  • Nostrils: Tiny openings beginning to form
  • Mouth: Small opening appearing
  • Ears: Small depressions on sides of head
  • Arms: Beginning to bend at primitive elbow
  • Legs: Slightly shorter than arms, thickening
  • Tail: Noticeably smaller

Key Visual Features:

Facial features are becoming more distinct. The eyes appear as dark spots still positioned on the sides of the head. You can see the beginnings of ears and nostrils. The limbs are developing definition, with arms slightly more advanced than legs.

Week 8: End of Embryonic Period

Size: 16-20mm (size of raspberry)
Overall appearance: Recognizably human with all basic features present

What You'd See:

  • Face: More human-like appearance
  • Eyes: Still closed but moving toward front of face
  • Nose: More defined with visible nostrils
  • Lips: Upper lip beginning to form
  • Ears: Small but recognizable ear buds
  • Arms: Elbows visible, hands forming
  • Legs: Knees forming, feet developing
  • Tail: Nearly disappeared

Key Visual Features:

Your baby now looks unmistakably human, albeit with a very large head. All major features are present: eyes, nose, mouth, ears, arms with developing hands, and legs with developing feet. The tail has almost completely disappeared. This marks the transition from embryo to fetus.

End of First Trimester: 9-12 Weeks Appearance

As you complete the first trimester, your baby's appearance becomes increasingly refined and human-like. All major features are present and continue to develop.

Week 9: Fetal Period Begins

Size: 22-25mm (size of cherry)
Overall appearance: Miniature human with more proportioned features

Detailed Appearance:

  • Head: Still large but better proportioned to body
  • Eyes: More prominent, developing eyelids
  • Nose: More defined bridge and tip
  • Mouth: Lips more formed, tongue developing
  • Neck: Beginning to separate head from body
  • Fingers: Individual digits becoming visible
  • Toes: Beginning to separate
  • Genitals: Present but not yet distinguishable

Body Proportions:

The head is still about half the total body length, but the torso is elongating. Arms and legs are more proportional, though still small compared to the head. The baby can make small movements, though they're not felt by the mother yet.

Week 10: Refined Features

Size: 30-35mm (size of strawberry)
Overall appearance: Well-proportioned miniature human

Detailed Appearance:

  • Facial features: More refined and human-like
  • Eyes: Developing color, still closed
  • Ears: Moving to proper position on sides of head
  • Hands: Fingers separated with tiny fingernails forming
  • Feet: Toes distinct with forming toenails
  • Skin: Translucent, blood vessels visible
  • Hair follicles: Beginning to form on scalp
  • Tooth buds: Present within gums

Movement and Positioning:

Your baby can now make complex movements including bending limbs, turning the head, and opening the mouth. These movements are becoming more coordinated and purposeful, though still too small to be felt.

Week 11: Growing and Stretching

Size: 45-50mm (size of fig)
Overall appearance: Rapidly growing with lengthening body

Detailed Appearance:

  • Body length: Doubling in size from previous weeks
  • Proportions: Head still large but body catching up
  • Facial profile: More distinct profile emerging
  • Limbs: Arms and legs growing rapidly
  • Joints: All major joints functional
  • External genitalia: Beginning to differentiate
  • Skin texture: Still very thin and transparent
  • Bone development: Ossification beginning

Key Changes This Week:

This is a period of rapid growth in body length. Your baby's torso is elongating significantly, making the overall proportions more human-like. The limbs are stretching and joints are becoming more functional.

Week 12: First Trimester Complete

Size: 55-65mm (size of lime)
Overall appearance: Fully formed miniature baby

Detailed Appearance:

  • Facial features: All present and well-defined
  • Eyes: Moving closer together, eyelids forming
  • Ears: In proper position with external ear forming
  • Limbs: Fully formed with functioning joints
  • Fingers and toes: Complete with forming nails
  • Sex organs: Beginning to be distinguishable
  • Reflexes: Present - can respond to touch
  • Movements: Active and coordinated

Milestone Appearance:

Your baby now looks like a tiny, perfectly formed human being. All major organs are present and functioning at basic levels. The appearance is that of a miniature newborn, just much smaller and with different proportions.

Early Second Trimester: 13-20 Weeks Visual Development

The second trimester brings significant changes in appearance as your baby grows rapidly and features become more refined and mature.

Weeks 13-16: Rapid Growth Phase

Size progression: 75mm to 116mm (3-4.5 inches)
Weight progression: 25g to 100g

Major Appearance Changes:

  • Proportions: Body growing faster than head
  • Neck: Clearly defined, separating head and body
  • Limbs: Longer and more proportional
  • Facial features: More refined and mature
  • Eyes: Moving to front of face, developing lashes
  • Ears: Nearly in final position
  • Hair: Fine hair (lanugo) covering body
  • Skin: Still transparent but thickening

Week 16 Specific Appearance:

By 16 weeks, your baby looks like a well-proportioned miniature person. The head, while still large, is better balanced with the body. Facial features are clearly defined, and you might be able to see expressions during ultrasound. The baby can make coordinated movements and may even be sucking their thumb.

Weeks 17-20: Anatomy Scan Period

Size progression: 130mm to 166mm (5-6.5 inches)
Weight progression: 140g to 300g

Detailed Visual Features:

Facial Development (Week 18-20):
  • Eyes: Fully formed but still closed, developing eyebrows
  • Nose: Well-defined with open nostrils
  • Lips: Full and well-formed
  • Ears: In proper position with detailed external structure
  • Expressions: Can make facial expressions including frowning
Body Development:
  • Proportions: More baby-like, head about 1/3 of body length
  • Limbs: Well-proportioned with defined muscles
  • Hands: Fully formed with individual fingerprints
  • Feet: Complete with toe prints forming
  • Skin: Less transparent, developing layers
  • Vernix: Protective coating beginning to form

What You See During Anatomy Scan:

During the 18-22 week anatomy scan, you'll see a baby that looks remarkably human. You can often see detailed facial features in profile, watch them move their hands and feet, and observe facial expressions. The baby may be sucking their thumb, covering their face with hands, or in various positions that show off their developing personality.

Late Second Trimester: 21-26 Weeks Appearance

During the late second trimester, your baby develops a more mature appearance with improved proportions and functioning systems.

Weeks 21-24: Viability Approaching

Size progression: 180mm to 213mm (7-8.5 inches)
Weight progression: 350g to 630g

Significant Appearance Developments:

  • Proportions: Becoming more newborn-like
  • Skin color: Red and wrinkled due to lack of fat
  • Eyes: Beginning to open and close
  • Eyebrows and eyelashes: Clearly visible
  • Hair: More substantial hair growth on head
  • Fingernails: Well-developed and growing
  • Footprints: Distinct ridges and patterns formed
  • Muscle definition: Becoming more apparent

Week 24 - Viability Milestone Appearance:

At 24 weeks, your baby looks like a very small newborn, though still quite thin and red. The face is well-formed with distinct features. Eyes can open and close, and the baby shows clear responses to light and sound. While still lean, muscle development is becoming more apparent, and the baby's movements are strong and coordinated.

Weeks 25-26: Continued Maturation

Size progression: 225mm to 240mm (9-9.5 inches)
Weight progression: 700g to 900g

Appearance Refinements:

  • Eyes: Can open and focus, developing color
  • Skin texture: Still wrinkled but less translucent
  • Hair color: Natural hair color beginning to show
  • Facial features: More defined and individual
  • Body fat: Beginning to accumulate, slightly fuller appearance
  • Lung development: Breathing movements visible on ultrasound
  • Startle response: Clear responses to loud noises
  • Taste buds: Fully formed, can taste amniotic fluid

Sensory Appearance:

Your baby now shows clear responses to external stimuli. You might see them startle during ultrasound, turn toward light sources, or make facial expressions in response to sounds. The eyes are becoming more active, and the baby can distinguish between light and dark.

Early Third Trimester: 27-32 Weeks Visual Development

The third trimester brings significant changes in appearance as your baby gains weight, develops fat stores, and prepares for life outside the womb.

Weeks 27-30: Filling Out

Size progression: 250mm to 270mm (10-10.5 inches)
Weight progression: 900g to 1.3kg

Major Appearance Changes:

  • Overall appearance: Less wrinkled, starting to fill out
  • Skin color: Less red, becoming more pink
  • Eyes: Open regularly, can track movement
  • Eyelashes: Long and well-defined
  • Hair: Thicker on head, body hair (lanugo) may start shedding
  • Fingernails: Growing beyond fingertips
  • Fat accumulation: Face becoming rounder
  • Muscle tone: Noticeably stronger and more defined

Week 28 Appearance:

Your baby is starting to look more like a chubby newborn rather than a thin fetus. The face is filling out, making features appear softer and more baby-like. Eyes are open much of the time, and you might catch them looking around during ultrasounds. The baby is very active and their movements are becoming quite strong.

Weeks 31-32: Rapid Weight Gain

Size progression: 280mm to 288mm (11-11.5 inches)
Weight progression: 1.5kg to 1.7kg

Notable Appearance Features:

  • Chubby appearance: Face and body noticeably rounder
  • Skin smoothness: Wrinkles filling out with fat deposits
  • Pink coloring: Healthier, less translucent skin
  • Defined features: All facial features clearly individual
  • Hair texture: Real hair replacing lanugo on head
  • Nail growth: May need trimming at birth
  • Eye movement: Coordinated eye movements and blinking
  • Expressions: Wide range of facial expressions

Individual Appearance:

By 32 weeks, your baby is developing their own unique appearance. Facial features that will characterize them as an individual are becoming apparent. You might start to see family resemblances during detailed ultrasounds, and their personality may begin showing through their movements and expressions.

Late Third Trimester: 33-40 Weeks Final Development

In the final weeks of pregnancy, your baby completes their development and prepares for birth, taking on the appearance of a full-term newborn.

Weeks 33-36: Pre-Term to Full-Term

Size progression: 300mm to 326mm (12-13 inches)
Weight progression: 1.9kg to 2.6kg

Appearance Refinements:

  • Plump appearance: Well-rounded body with good fat stores
  • Smooth skin: Most wrinkles filled out
  • Pink and healthy: Good circulation shows healthy coloring
  • Mature features: Fully developed facial characteristics
  • Hair fullness: Head hair becoming thicker
  • Lanugo shedding: Most body hair disappearing
  • Vernix coating: Protective layer still present
  • Coordinated movements: Purposeful and strong movements

Week 36 - Early Term Appearance:

Your baby now looks like a full-term newborn, just slightly smaller. The face is round and full, skin is smooth and pink, and all features are completely mature. The baby may be getting into position for birth, and their movements, while still active, are becoming more limited due to space constraints.

Weeks 37-40: Full-Term Ready

Size progression: 340mm to 360mm (13.5-14 inches)
Weight progression: 2.9kg to 3.4kg

Birth-Ready Appearance:

  • Newborn appearance: Looks exactly like a term baby
  • Optimal weight: Good fat stores for temperature regulation
  • Mature skin: Smooth, pink, and well-developed
  • Complete features: All characteristics fully developed
  • Hair pattern: Established hair color and texture
  • Eye development: Can focus and track objects
  • Nail length: Long nails that may scratch face
  • Positioning: Likely head-down for birth

Week 40 - Due Date Appearance:

Your baby looks exactly like a newborn baby ready for the outside world. They have a plump, healthy appearance with smooth pink skin, well-developed features, and strong muscle tone. The protective vernix is mostly absorbed, and most of the lanugo has disappeared. Your baby is perfectly formed and ready for birth.

Facial Feature Development Throughout Pregnancy

The development of your baby's facial features is one of the most fascinating aspects of fetal development. Here's how each feature develops and changes.

Eye Development Timeline

Weeks 4-6: Eye Formation

  • Dark spots appear on sides of head
  • Eye cups form from neural tissue
  • Eyes positioned far apart on head
  • Lens and cornea begin developing

Weeks 7-12: Eye Migration

  • Eyes gradually move toward front of face
  • Eyelids begin forming
  • Eye color starts developing (iris formation)
  • Basic eye structure complete by week 12

Weeks 13-20: Refinement

  • Eyes properly positioned on front of face
  • Eyelids fused shut for protection
  • Eyebrows and eyelashes begin growing
  • Tear ducts developing

Weeks 24-28: Eye Opening

  • Eyelids begin to separate
  • Eyes can open and close
  • Can distinguish light from dark
  • Eye movements become coordinated

Weeks 28-Birth: Maturation

  • Eyes open regularly
  • Can focus on objects
  • Responds to bright lights
  • Eye color continues developing (may change after birth)

Nose Development Timeline

Weeks 5-7: Nasal Formation

  • Nasal pits appear as small depressions
  • Nasal prominences form on either side
  • Beginning of nostrils development

Weeks 8-12: Structure Development

  • Nasal bridge begins forming
  • Nostrils become more defined
  • Tip of nose starts forming
  • Nasal passages developing internally

Weeks 13-20: Refinement

  • Nose becomes more prominent
  • Individual nose shape becoming apparent
  • Nasal cartilage developing
  • Smell receptors forming

Weeks 20-Birth: Final Shaping

  • Nose takes on final shape
  • Nostrils fully formed and functional
  • Can distinguish some odors
  • Individual characteristics apparent

Mouth and Lip Development

Weeks 6-8: Mouth Formation

  • Mouth opening begins as small depression
  • Upper and lower lip buds form
  • Tongue begins developing

Weeks 9-12: Lip Definition

  • Upper lip forms distinctive shape
  • Lower lip becomes well-defined
  • Mouth can open and close
  • Palate formation completing

Weeks 13-20: Functional Development

  • Sucking reflex develops
  • Taste buds form on tongue
  • Can make various mouth movements
  • May begin thumb sucking

Weeks 20-Birth: Refinement

  • Strong sucking reflex established
  • Can distinguish different tastes
  • Facial expressions include mouth movements
  • Ready for feeding at birth

Ear Development Timeline

Weeks 6-8: Ear Formation

  • Six small bumps appear on sides of head
  • These hillocks will form external ear
  • Inner ear structures beginning

Weeks 9-16: Ear Shaping

  • External ear (auricle) takes shape
  • Ears positioned low on head initially
  • Inner ear developing for balance and hearing

Weeks 16-24: Position and Function

  • Ears migrate to proper position on head
  • Hearing structures mature
  • Can begin to hear sounds around 18-20 weeks

Weeks 24-Birth: Hearing Maturation

  • Fully functional hearing
  • Responds to familiar voices
  • Can distinguish different sounds and music
  • External ears in final position and shape

Body Proportion Changes Throughout Pregnancy

One of the most dramatic changes during fetal development is how body proportions shift from the large-headed early embryo to the well-proportioned newborn.

Early Development (4-8 weeks)

Head-to-Body Ratio: 1:1

In early development, the head makes up about half of the entire body length. This massive head size is necessary to accommodate the rapidly developing brain.

  • Head: Dominates overall appearance
  • Torso: Very short and compact
  • Limbs: Tiny buds, barely visible
  • Overall shape: C-curved with prominent head

Late First Trimester (9-12 weeks)

Head-to-Body Ratio: 1:1.5

The body begins catching up to the head size, though the head remains proportionally very large compared to a newborn.

  • Head: Still very large but slightly better proportioned
  • Torso: Elongating and becoming more defined
  • Limbs: Clearly visible arms and legs
  • Neck: Beginning to separate head from body

Second Trimester (13-26 weeks)

Head-to-Body Ratio: 1:2 to 1:2.5

This is a period of rapid body growth. The torso elongates significantly, and limbs grow in proportion to create a more balanced appearance.

  • Head: About 1/3 of total body length
  • Torso: Major growth period, becoming well-proportioned
  • Limbs: Growing rapidly in length and definition
  • Overall appearance: More human-like proportions

Third Trimester (27-40 weeks)

Head-to-Body Ratio: 1:3 to 1:4

The final trimester focuses on filling out and achieving newborn proportions. Fat accumulation creates the rounded, healthy appearance of a term baby.

  • Head: About 1/4 of total body length (newborn ratio)
  • Torso: Fully proportioned with fat accumulation
  • Limbs: Chubby and well-developed
  • Overall appearance: Newborn proportions achieved

Comparative Proportions

Gestational Age Head % Torso % Limbs % Overall Appearance
6 weeks 50% 35% 15% Large head dominates
12 weeks 45% 40% 15% Head still large but body catching up
20 weeks 35% 45% 20% More balanced proportions
32 weeks 28% 50% 22% Nearly newborn proportions
40 weeks 25% 52% 23% Newborn proportions achieved

Skin and Hair Development

The development of your baby's skin and hair is a gradual process that transforms from transparent, thin skin to the protective barrier needed for life outside the womb.

Skin Development Timeline

Weeks 4-12: Basic Skin Formation

Appearance: Extremely thin and transparent

  • Transparency: Blood vessels clearly visible
  • Texture: Smooth but very delicate
  • Color: Pink-red due to visible circulation
  • Thickness: Single layer of cells initially
  • Function: Basic protection beginning to develop

Weeks 13-20: Skin Thickening

Appearance: Still translucent but developing layers

  • Layer development: Multiple skin layers forming
  • Blood vessels: Still visible but less prominent
  • Hair follicles: Beginning to form
  • Sweat glands: Starting to develop
  • Fingerprin ridges: Forming unique patterns

Weeks 20-28: Protective Features

Appearance: Less transparent, beginning to look more opaque

  • Vernix caseosa: Protective waxy coating begins forming
  • Lanugo: Fine hair covering entire body
  • Wrinkled appearance: Due to lack of fat underneath
  • Red coloring: Still quite red and thin
  • Sebaceous glands: Producing protective oils

Weeks 28-36: Fat Accumulation

Appearance: Smoother and less wrinkled as fat accumulates

  • Subcutaneous fat: Beginning to fill out wrinkles
  • Color change: Becoming less red, more pink
  • Smoother texture: Wrinkles filling out
  • Vernix thickening: Protective coating more substantial
  • Lanugo shedding: Body hair beginning to disappear

Weeks 36-Birth: Newborn Skin

Appearance: Smooth, pink, and healthy-looking

  • Plump appearance: Good fat layer underneath
  • Pink coloring: Healthy circulation, less red
  • Smooth texture: Most wrinkles filled out
  • Protective barrier: Fully functional skin barrier
  • Birth-ready: Prepared for outside environment

Hair Development Timeline

Weeks 14-16: Hair Follicle Formation

  • Hair follicles form on scalp
  • Hair pattern (including future hairline) established
  • Color-producing cells (melanocytes) begin developing
  • No visible hair yet

Weeks 16-20: Lanugo Development

  • Fine, downy hair (lanugo) covers entire body
  • Usually colorless or very light
  • Helps hold vernix caseosa in place
  • Most prominent on shoulders and back

Weeks 20-28: Head Hair Emergence

  • Real hair begins growing on scalp
  • May be different color than adult hair will be
  • Eyebrows and eyelashes become visible
  • Hair texture begins establishing

Weeks 28-36: Hair Maturation

  • Head hair becomes thicker and more substantial
  • Natural hair color becomes more apparent
  • Lanugo begins shedding on face and front of body
  • Some babies born with full heads of hair, others with very little

Weeks 36-Birth: Final Hair Development

  • Most lanugo shed (some may remain at birth)
  • Head hair at birth varies greatly between babies
  • Hair color and texture may change significantly after birth
  • Eyebrows and eyelashes well-developed

Important Hair Development Facts:

  • Individual variation: Some babies are born with lots of hair, others with very little - both are normal
  • Color changes: Hair color at birth may be completely different from adult hair color
  • Texture changes: Straight hair at birth may become curly, and vice versa
  • Lanugo is normal: Some lanugo at birth is normal, especially on shoulders and back
  • Hair loss: Many babies lose their birth hair in the first few months

Size Comparisons Throughout Pregnancy

Understanding your baby's size at different stages helps visualize their incredible growth. These comparisons use everyday objects to help you picture your baby's development.

Complete Size Comparison Chart

Week Size Comparison Length (Crown-Rump) Weight Key Visual Features
4 Poppy seed 2-4mm <1g Curved, tail visible, large head region
6 Lentil 8-12mm 1g Heart beating, limb buds, eye spots
8 Raspberry 16-20mm 2g Human-like, tail disappearing, facial features
10 Strawberry 30-35mm 4g Fingers separating, facial refinement
12 Lime 55-65mm 14g All organs formed, recognizable human
14 Lemon 85mm 25g Rapid growth, better proportions
16 Avocado 116mm 100g Sex distinguishable, coordinated movement
18 Bell pepper 140mm 190g Active movement, forming fingerprints
20 Banana 166mm 300g Anatomy scan visible, movement felt
22 Papaya 190mm 430g Hearing developed, taste buds functional
24 Ear of corn 213mm 630g Viability milestone, eyes can open
26 Scallion bundle 240mm 900g Strong movements, established sleep cycles
28 Eggplant 251mm 1005g Third trimester, rapid brain development
30 Cabbage 270mm 1320g Filling out, less wrinkled appearance
32 Jicama 288mm 1702g Chubby appearance, coordinated sucking
34 Cantaloupe 320mm 2146g Smooth skin, substantial weight gain
36 Romaine lettuce 326mm 2622g Nearly full-term appearance
38 Winter melon 356mm 3083g Full-term, birth-ready appearance
40 Small pumpkin 360mm 3462g Newborn appearance, ready for birth

Growth Pattern Insights

Length Growth

Your baby's length increases most dramatically between weeks 12-20, when they grow from about 2.5 inches to over 6 inches. Growth then continues more gradually through the third trimester.

Weight Growth

Weight gain follows an exponential pattern, with the most dramatic increases occurring in the third trimester. Your baby gains about half their birth weight in the last 8 weeks of pregnancy.

Proportional Changes

The most significant proportional changes occur in the second trimester when the body "catches up" to the head size, creating more balanced, human-like proportions.

Individual Variation

These measurements represent averages. Individual babies can vary significantly in size while still being perfectly healthy. Your baby's growth pattern is unique to them.

Medical Disclaimer: This information is for educational purposes only and should not replace professional medical advice. Fetal development can vary significantly between individuals, and the descriptions provided represent typical development patterns. Every pregnancy is unique, and your baby's appearance and development timeline may differ from these general descriptions. Always consult with your healthcare provider about your specific pregnancy and any concerns about fetal development. Ultrasound images and measurements from your healthcare provider are more accurate than general descriptions for your individual pregnancy.