Pregnancy week by week

Forty weeks. No doom-scroll.

What's happening to your baby. What's happening to you. When the heartbeat starts to come through your phone. A journal prompt for each week. Pick a week to start.

The full timeline

0.04″ · <0.01oz

Implantation. The first cells of your baby are nestling into the uterus.

0.05″ · <0.01oz

The neural tube is forming — the future brain and spinal cord.

0.25″ · <0.01oz

The heart starts to beat — though far too quiet to hear from outside.

0.4″ · 0.02oz

Baby has doubled in size in a week. The face is starting to take shape.

0.6″ · 0.04oz

All major organs are forming. Fingers and toes are beginning to separate.

0.9″ · 0.07oz

Embryo officially becomes a fetus next week. Tiny teeth buds are forming in the gums.

1.2″ · 0.14oz

Officially a fetus, no longer an embryo. Vital organs are functioning.

1.6″ · 0.25oz

Baby's hands and feet are no longer webbed. Fingers and toes are fully separated.

2.1″ · 0.5oz

End of the first trimester. The miscarriage risk drops significantly. Time to tell people, if you want to.

2.9″ · 0.81oz

Vocal cords are forming. Baby has fingerprints now — uniquely theirs forever.

3.4″ · 1.5oz

Welcome to the second trimester. The golden window starts here.

Baby is developing taste buds and can sense light through your belly.

4.6″ · 3.5oz

Heartbeat is now strong enough to hear via office doppler — and sometimes via Cudly.

5.1″ · 5.0oz

Baby is putting on fat now — the start of the chubbiness that's coming.

5.6″ · 6.7oz

Quickening — some women feel first flutters this week.

Vernix caseosa — that white waxy coating — is forming on baby's skin.

6.5″ · 10.6oz

Halfway there. Anatomy scan happens this week or next.

10.5″ · 12.7oz

Baby's movements are no longer subtle. You'll be sure now.

10.9″ · 15.2oz

Baby has well-developed eyebrows, fingernails, lips. They look like a tiny person.

11.4″ · 17.6oz

Baby's hearing is now sharp enough to recognize voices they hear often.

11.8″ · 21oz

Viability week. If born now, baby has a real chance with NICU care.

13.6″ · 24.7oz

Baby is starting to respond to your voice — they may move when you talk.

14″ · 28.1oz

Baby's eyes are about to open for the first time.

14.4″ · 31.9oz

Last week of the second trimester. Baby's brain is busy this week.

14.8″ · 35.3oz

Welcome to the third trimester.

Butternut squash

15.2″ · 39.2oz

Baby's bones are fully developed but still soft. Muscle and lung development is the focus now.

15.7″ · 43.3oz

Baby's brain wrinkles and grows more sophisticated by the day.

16.2″ · 48.1oz

All five senses are working. Baby can see, hear, taste, smell, and feel.

16.7″ · 60.0oz

Baby is practicing breathing motions in earnest now.

17.2″ · 67.7oz

Baby's immune system is getting a boost — antibodies passing from you to them.

17.7″ · 75.2oz

Vernix is thickening. The protective coating that'll be on baby at birth.

18.2″ · 83.2oz

Kidneys are fully developed. Liver can process some waste. Baby is mostly just gaining weight now.

Romaine lettuce

18.7″ · 92.6oz

Term-ish. Baby could come at any time and be fine.

19.1″ · 100.3oz

Officially "early term." Baby is ready for the world.

19.6″ · 108.4oz

Baby's brain and nervous system are still developing — and will continue long after birth.

Mini watermelon

19.9″ · 117.3oz

Full term. Baby is officially done cooking.

20.2″ · 127.9oz

Your due date. Most babies are born within 2 weeks either side.

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