Pregnancy Week by Week

Week 1

Week 1 of pregnancy is actually the week of your last menstrual period. Your body is preparing for ovulation, and this is the best time to start preconception preparation.

Week 2

Week 2 is when ovulation happens — your most fertile window. Conception typically occurs this week or early next week. Here's what's happening inside your body.

Week 3

Fertilization has occurred! A single-celled zygote — carrying your baby's complete DNA — is now dividing rapidly and traveling toward your uterus for implantation.

Week 4

The blastocyst implants in your uterine lining this week. The placenta begins forming, hCG starts rising, and a home pregnancy test may finally show positive.

Week 5

Your baby's brain and spinal cord are forming this week. The heart tube is forming and may begin its first contractions. Morning sickness may arrive with full force.

Baby size: sesame seed

Week 6

Your baby's heartbeat is now detectable on a vaginal ultrasound. Tiny arm and leg buds have emerged, and blood circulation has begun. You're likely feeling the full force of first trimester symptoms.

Baby size: lentil

Week 7

Your baby is now ~10mm — the size of a blueberry. Limbs are elongating, the brain is growing rapidly, and the head is disproportionately large.

Baby size: blueberry

Week 8

Your baby is now officially a fetus! All major organs are developing, tiny fingers are forming, and you're likely in the thick of morning sickness.

Baby size: kidney bean

Week 9

Your baby is forming tooth buds and taste buds this week. Muscles are developing, and the heartbeat may be audible on Doppler. Nausea is likely still at its peak.

Baby size: grape

Week 10

Your baby's arms, hands, and fingers are fully formed! Fingernails are beginning to grow and external genitals are forming. Nausea should start easing soon.

Baby size: olive

Week 11

Your baby can open and close fists and mouth! Bones are hardening while skin is still transparent. The NT scan window is now open — time to book it.

Baby size: fig

Week 12

A major milestone — all organs, limbs, bones, and muscles are in place. Your baby's circulatory and digestive systems are working. Miscarriage risk drops significantly.

Baby size: plum

Week 13

The last week of your first trimester! Your baby's vocal cords are forming and the head is proportioning to the body. Welcome to the transition into the second trimester.

Baby size: lemon

Week 14

Welcome to the second trimester! Your baby's skin is thickening, fingerprints are forming, and you might finally be getting your energy back.

Baby size: lemon

Week 15

Your baby's organs are moving into their permanent positions, lungs are developing, and you're likely feeling more energetic than you have in weeks.

Baby size: apple

Week 16

Your baby is now the size of an avocado, weighing about 100g. Lips are fully formed, ears can hear your voice, and eyes react to light.

Baby size: avocado

Week 17

Your baby is starting to store fat under the skin, and a white protective coating called vernix is forming. Growth is accelerating.

Baby size: avocado

Week 18

Your baby is covered in fine lanugo hair, developing a sleep-wake cycle, and can now respond to loud noises. The anomaly scan window opens.

Baby size: mango

Week 19

Your baby's unique fingerprints are set, hiccupping has begun, and you'll likely feel those first magical kicks this week.

Baby size: mango

Week 20

Halfway there! Your baby's brain is developing sensory areas, the anomaly scan window is open, and baby weighs about 300g.

Baby size: papaya

Week 21

Your baby is making coordinated movements, bone marrow is producing blood cells, and you're well into the second trimester groove.

Baby size: papaya

Week 22

Your baby is the size of a papaya (~28cm) and developing a stronger grip. They can hear your heartbeat and digestive sounds. Learn about symptoms, tests, and what to expect this week.

Baby size: papaya

Week 23

Week 23 — your baby (~30cm) is approaching the viability milestone. Baby is rapidly adding fat and lungs are developing.

Baby size: papaya

Week 24

Your baby weighs about 600g (~32cm) and lungs are developing but not ready. GDM screening window is open. Learn about tests, symptoms, and development this week.

Baby size: coconut

Week 25

Your baby is about 35cm and 700g — body fat is increasing and the nervous system is maturing rapidly. Learn about symptoms, nutrition, and what to watch for.

Baby size: coconut

Week 26

Your baby is about 36cm and lungs are now producing surfactant — a major milestone. Melanin production begins. Learn about symptoms, tests, and what's ahead.

Baby size: coconut

Week 27

Your baby weighs about 900g (~37cm) — eyes open and blink for the first time! Eyelashes are present and REM sleep begins. Last week of the second trimester.

Baby size: coconut

Week 28

Third trimester begins! Your baby weighs 1-1.3 kg (~38cm), may turn head-down, and eyes respond to light. Kick counting starts now. Anti-D injection for Rh-negative mothers.

Baby size: coconut

Week 29

Your baby weighs about 1.2 kg (~39cm) — space is getting tight. Bones are actively storing calcium, iron, and phosphorus. Learn about third trimester symptoms and what to watch for.

Baby size: coconut

Week 30

Your baby weighs about 1.3 kg (~40cm) and body fat including brown fat is accumulating for temperature regulation. Brain is maturing rapidly. 10 weeks to go — learn about symptoms and preparation.

Baby size: coconut

Week 31

Your baby weighs about 1.5 kg and is processing more information than ever. Distinct sleep/wake cycles are now established, and you're feeling every kick.

Baby size: coconut

Week 32

Your baby weighs about 1.7 kg and skin is no longer translucent. Most organs are ready except lungs and brain. Time for your growth scan.

Baby size: coconut

Week 33

Your baby weighs about 2 kg and bones are hardening — except the skull bones, which stay soft to pass through the birth canal. Seven weeks to go.

Baby size: pumpkin

Week 34

Your baby weighs about 2.2 kg, vernix is thickening, and lungs are maturing. If born now, baby has excellent survival chances with minimal NICU time.

Baby size: pumpkin

Week 35

Your baby weighs about 2.5 kg — brain weighs two-thirds of its final weight. Fat stores increasing rapidly. Time to pack your hospital bag.

Baby size: pumpkin

Week 36

Your baby weighs about 2.7 kg — lanugo is shedding and hair is growing. GBS screening window. Weekly visits start. Hospital bag should be packed and ready.

Baby size: watermelon

Week 37

Early term! Your baby weighs about 2.9 kg. Toenails reach toe ends. Baby may drop into the pelvis. You could go into labor any day now.

Baby size: watermelon

Week 38

Your baby weighs about 3.1 kg — gaining 200g per week. Lungs are mature. Brain and liver are still developing. Labor could start any day.

Baby size: watermelon

Week 39

Full term! Your baby weighs about 3.3 kg — all systems are ready. The ideal delivery window has begun. Know the signs of labor and when to head to the hospital.

Baby size: watermelon

Week 40

Your due date is here! Baby weighs about 3.5 kg. But only 5% of babies arrive on their due date. Here's what to expect, when to go to hospital, and what happens if you go overdue.

Baby size: watermelon