Week-by-week milestones

Track your baby's growth from poppy seed to watermelon

Week 41st tri

Size of a poppy seed

Length: ~1mmWeight: <1g

Embryo implants in the uterine wall. The neural tube, which becomes the brain and spinal cord, is forming.

Week 51st tri

Size of a sesame seed

Length: ~2mmWeight: <1g

The heart begins to beat! The brain is dividing into 5 areas and cranial nerves are visible.

Week 61st tri

Size of a lentil

Length: ~6mmWeight: <1g

Nose, mouth, and ears are taking shape. Arm and leg buds have appeared.

Week 71st tri

Size of a blueberry

Length: ~13mmWeight: <1g

Hands and feet are emerging. The brain generates roughly 100 new cells every minute.

Week 81st tri

Size of a raspberry

Length: ~16mmWeight: ~1g

All essential organs have begun forming. Tiny fingers and toes are developing.

Week 91st tri

Size of a cherry

Length: ~23mmWeight: ~2g

Muscles are forming and tiny movements begin. The heart finishes dividing into 4 chambers.

Week 101st tri

Size of a strawberry

Length: ~31mmWeight: ~4g

All vital organs are formed and beginning to function together. Fingernails start developing.

Week 111st tri

Size of a lime

Length: ~41mmWeight: ~7g

Baby can open and close fists. Tooth buds appear under the gums.

Week 121st tri

Size of a plum

Length: ~54mmWeight: ~14g

Reflexes developing — baby can squint, open mouth, move fingers. Kidneys produce urine.

Week 131st tri

Size of a lemon

Length: ~74mmWeight: ~23g

Fingerprints forming! Vocal cords developing. Entering the second trimester.

Week 142nd tri

Size of a nectarine

Length: ~87mmWeight: ~43g

Baby can squint and frown. Thyroid gland starts producing hormones.

Week 162nd tri

Size of a avocado

Length: ~12cmWeight: ~100g

Bones hardening. You may feel first flutters of movement (quickening).

Week 182nd tri

Size of a sweet potato

Length: ~14cmWeight: ~190g

Baby can hear sounds from the outside world! Myelin coating the nerves.

Week 202nd tri

Size of a banana

Length: ~16cmWeight: ~300g

Halfway there! Vernix coating developing. Baby can taste flavours. Anatomy scan happens now.

Week 222nd tri

Size of a papaya

Length: ~19cmWeight: ~430g

Baby's grip is strong. Eyebrows and eyelids fully formed. Can sense light and dark.

Week 242nd tri

Size of a ear of corn

Length: ~21cmWeight: ~600g

Lungs developing branches. Baby responds to sounds regularly. Considered viable.

Week 262nd tri

Size of a zucchini

Length: ~23cmWeight: ~760g

Eyes opening for the first time. Brain wave activity for hearing and sight detectable.

Week 283rd tri

Size of a eggplant

Length: ~25cmWeight: ~1kg

Baby can blink! REM sleep cycles begin. Hiccups common. Third trimester starts.

Week 303rd tri

Size of a cabbage

Length: ~27cmWeight: ~1.3kg

Brain growing rapidly with billions of neurons. Baby may be practising breathing.

Week 323rd tri

Size of a squash

Length: ~28cmWeight: ~1.7kg

Toenails visible. Skin becoming smooth as fat layers develop. Bones fully formed but soft.

Week 343rd tri

Size of a cantaloupe

Length: ~30cmWeight: ~2.1kg

Central nervous system maturing. Lungs nearly fully mature.

Week 363rd tri

Size of a honeydew melon

Length: ~32cmWeight: ~2.6kg

Most organs ready for life outside. Fat layer growing. Head may engage in pelvis.

Week 383rd tri

Size of a pumpkin

Length: ~34cmWeight: ~3.0kg

All organs mature and functioning. Brain and lungs continue fine-tuning.

Week 403rd tri

Size of a watermelon

Length: ~36cmWeight: ~3.4kg

Full term! Baby is ready to meet the world. Average weight 3–4kg (7–8 lbs).