#1. Just 4 days after fertilization.
Although it doesn’t look like much, this microscopic zygote has a unique set of DNA, a sex (it’s a girl!), and is how we all started out.
#2. Around 5-6 weeks of gestation.
Although she’s only a quarter of an inch long, you can clearly see eyes and ears taking shape. She already has blood circulating her body, detectable brain waves, and a heart rate of around 100 beats per minute.
#3. And two weeks later.
Amazingly, at 7 weeks gestation the foetus has already used three sets of kidneys. She also has a tiny tail but she’ll lose that soon.
#4. Around 10 weeks.
This baby now has most of her major organs, including kidneys (the final set), intestines, a brain, and liver. She can flex her arms and legs, her ears have nearly reached their final position, and she now has hair follicles and fingernails.
#5. 12 weeks.
At 12 weeks a baby is flexing its new muscles, so a mom will start to feel a lot of wriggling in her tummy. Her eyes have moved from the side of her head to the front and she’s practicing breathing.
#6. Just one month later.
Now at weeks of gestation, this baby is about the size of an avocado and is trying out facial expressions for the first time. Her skin is still translucent, with blood vessels visible beneath, and she might grab the umbilical cord as her grip strength grows.
#7. 18-20 weeks gestation (and already sucking her thumb).
Now weighing 240g and 14cm long, cartilage starts turning into bone and the baby’s kicks become harder. She’s developing her skin tone as pigment develops and it’s thought that babies can hear their mom’s voice around this time.
#8. 6 months gestation.
This is the first time that, if born prematurely, this baby could possibly survive. She’s gaining weight steadily, now weighing around 600g, with lungs beginning to breathe air rather than fluid (which can cause hiccups).
#9. 7 months gestation, not long to go.
Putting on around half a pound a week, this baby is also busy practicing breathing, sucking, swallowing, and kicking. She has dreams when she sleeps, and, unless she’s breech, she’s moved into position ready for birth.
#10. Ready to say hello.
Now weighing around 7lbs and at 50% body fat, this baby is a fully-formed little person ready to come and meet her family.