What Your Baby Really Looks Like This Week — A Complete Week-by-Week Guide

Pregnancy is one of the most extraordinary journeys of life — from a tiny cluster of cells to a fully formed baby ready to be born. Every week, your baby changes in incredible ways. Below is a detailed, medically updated week-by-week guide to what your baby looks like inside the womb — from fertilization all the way to full term.

🌱 First Trimester (Weeks 1–12): From Fertilization to Tiny Human

Weeks 1–3: Conception Begins

  • Week 1–2: You aren’t technically pregnant yet — this counts from your last menstrual period.

  • Week 3: Fertilization occurs — a sperm and egg join to form a zygote. It begins dividing into many cells as it travels down to implant in the uterus. Mayo Clinic

Weeks 4–5: Embryo Takes Shape

  • Week 4: The embryo implants in the uterine lining. You might see the gestational sac on ultrasound.

  • Week 5: The embryo is only a few millimeters long, with a tiny heart beginning to beat and initial brain and spinal cord forming. Mayo Clinic+1

Weeks 6–7: Early Features Form

  • Arm and leg buds appear. The head is large compared to the body, and the brain is growing rapidly. Major organs start forming. Mayo Clinic

Weeks 8–9: Human Features Emerge

  • Tiny fingers and toes start to become visible.

  • The face begins to form: eyes, nose, and mouth shape up.

  • By the end of week 9, your baby is distinctly human-like in shape, though still very small. Mayo Clinic+1

Weeks 10–12: Fetus & Features Refine

  • At week 10, the embryo is now called a fetus.

  • Limbs can bend; eyelids and external ears continue developing.

  • By week 12, all major body parts exist — fingers, toes, facial features — though tiny and still growing. Mayo Clinic

🧠 What You’d See: In early scans, your baby may resemble a tiny curled shape, like a miniature human with a proportionally large head — not fully human in detail, but unmistakably forming into one. fetalbook.com

🧬 Second Trimester (Weeks 13–27): Rapid Growth & Movement

Week 13–16: Bone & Feature Development

  • Week 13: Bones start hardening; vocal cords form.

  • Week 14: Neck becomes more defined, red blood cells form in the spleen.

  • Week 16: Eyes move; ears are near final position. Mayo Clinic+1

Week 17–20: Movement & Reflexes

  • Week 17: Toenails develop.

  • Week 18: Hearing begins — your baby can likely hear your voice! Mayo Clinic

Week 19–24: Skin, Senses & Size

  • A protective coating called vernix begins covering the skin.

  • By week 21–22, lanugo (fine hair) covers the body.

  • Fingerprints and footprints form around week 23. Mayo Clinic

Week 25–27: Stronger Movements

  • Your baby may respond to sound and familiar voices.

  • Eyebrows and eyelashes form; the nervous system matures. Mayo Clinic

🖼️ What You’d See: By mid-pregnancy ultrasounds, your baby looks like a tiny fully shaped human with coordinated limb movements — often seen kicking, stretching, and turning. Mayo Clinic

👶 Third Trimester (Weeks 28–40): Fat Gain & Final Maturity

Week 28–32: Eyes Open & Weight Increase

  • Around week 28, eyelids can open and close.

  • Skin becomes less wrinkled as fat accumulates.

  • By week 32, your baby may be ~17 inches long, with organs continuing to mature. Parents

Week 33–36: Preparing for Life Outside

  • Significant weight gain.

  • Practice breathing movements; brain and lungs mature.

Week 37–40: Full Term

  • By week 37, the baby is considered early term.

  • Weeks 39–40: Your baby looks just like a newborn — plump, fully formed features, well-developed skin, and ready for birth. fetalbook.com

🎯 What You’d See: In late-pregnancy imaging, your baby’s face, hands, feet, and body look very much like they will at birth — robust, with smooth skin and clear human features. fetalbook.com

Optional Size Comparisons

Many pregnancy trackers compare your baby’s size to fruit or everyday objects — for example:

  • Week 5: tiny sesame seed.

  • Week 12: plum-size fetus.

  • Week 20: banana-sized baby.

  • Week 32+: Napa cabbage or larger. WebMD+1

In Summary

Your baby’s development is a remarkable progression:

  • Early weeks: microscopic embryo forming basic structures.

  • Mid-pregnancy: organs develop, reflexes form, movements begin.

  • Late pregnancy: rapid growth, fat accumulation, and preparation for life outside the womb.

This guide gives a clear and medically informed picture of how your baby grows from week to week — more accurate than older snapshot posts, and based on up-to-date clinical development research. 

👶 Third Trimester (Weeks 28–40): Getting Ready for Birth

Week 28–32

  • Eyes open and close; lungs and brain continue maturing. MSD Manuals

Week 33–36

  • Rapid weight gain; baby shifts into head-down position. MSD Manuals

Week 37–40

  • Considered full term around week 39.

  • Baby ~ 18–20 inches long and often weighs 6–9+ pounds. March of Dimes

In late pregnancy, ultrasounds show a baby with developed features, clear limbs, and facial details — often looked at by parents and doctors alike. Parents

📌 Size & Feature Comparison by Stage

StageApprox SizeKey Features
Week 4MicroscopicImplantation
Week 8~1.6 cmLimb buds, heartbeat visible
Week 12~8 cmFull fingers/toes, organs
Week 20~25 cmMovement felt, reflexes
Week 28~37 cmEyelids can open
Week 40~50+ cmFull-term baby ready for birth

Comments

laya said…
Thanks for posting. A quick advice for pregnant ladies.Gynecologist In Medavakkam and Gynecologist In Madipakkam will give you the best treatment, they are focused in your health and comfort. You should look over the best infrastructure where you can adapt without any problem like cm hospital.
August 21, 2019 at 10:55 PM
Post a Comment

Popular posts from this blog

The Effects of Pregnancy in Oral Health

By Robert Melkonyan Pregnancy can have different effects in the woman's overall health condition. Most pregnant women can notice some changes in the gums throughout pregnancy, including redness and bleeding of the gums when brushing the teeth. In addition, some women can experience severe bleeding and swelling. These changes are known pregnancy gingivitis that usually starts on the second month of the pregnancy. Pregnancy gingivitis tends to increase around eight month and may decrease after giving birth. This condition is usual in the front area of the mouth. The symptoms of pregnancy gingivitis are the same with the common gingivitis but may have different causes. Progesterone level in the body during pregnancy can reach up to ten percent higher than the normal level, which can improve certain bacterial growth that results to gingivitis. In addition, during pregnancy, the immune system works differently, which can change the body's reaction to bacteria. To be able to re...
Read more

10 Tips for Better Sleep During Pregnancy

Pregnancy is hard work, and you'll need your sleep. One of the cruel realities is that a good night's sleep during pregnancy remains elusive, if not impossible for most pregnant women, at some point during their pregnancy. While you might not be able to sleep like a baby, there are some ways you can improve your chances for better sleep during pregnancy. 1. Exercise . Getting your self good and tired out can't hurt your chances of getting some quality shut eye. It's also been shown that regular exercise can reduce the frequency of leg cramps, which many women are more prone to during pregnancy. Just don't exercise within a couple of hours of bedtime — that rush of endorphins and adrenaline can keep you awake long after you've hit the sack. 2. Relaxation . You should incorporate some forms of relaxation into your day, and particularly as part of your bedtime routine. Yoga is a good form of both exercise and relaxation, just be sure that you're following a ...
Read more

10 ways to survive stress in pregnancy

What causes stress during pregnancy? The sources of stress during pregnancy can be wide-ranging, from concern about your baby's health and wellbeing , or the impending labour, through to how you'll manage after the birth. It could be that your journey to work is exhausting, or you're anxious about finances and how you are going to afford all the costs involved with a new baby. Whatever it is that's worrying you, there are many positive steps you can take to overcome these feelings. 1. Make time to rest Advertisement It's a simple thing, but sometimes so difficult to take time out for yourself. Not only is this good for you, but also extremely good for your baby - so don't feel guilty about 'doing nothing'. It is ok to say “no” when you don’t have the energy to take on extra chores even if you do have the time. At work, find somewhere to put your feet up and relax during your lunch break and, in the evenings, try to cut down on chores. ...
Read more