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Week 1-4
The baby is is currently a ball of cells called blastocyst, and has a full set of DNA which determines sex, eye color, and other traits. By week four the baby has become an embryo, which is about the size of a poppy seed. -
Week 5-8
The baby's heart begins to beat at twice the rate of yours. Facial features like eyes and nostrils begin to form, and little buds form where the arms and legs will be. By the eighth week the arms and legs are growing, and the baby has fingers as well as an upper lip and a nose. -
Week 9-12
The baby eyes have developed but eyelids are shut, they've lost their 'tail' and are looking more human. They embryo is now a fetus, and vital organs like kidneys, liver, brain and intestines are functioning. By the 11th week the baby is almost fully formed, the bones are hardening and the genitalia are forming externally. Eventually by the 12th week you can hear the baby's heartbeat. -
Week 13-16
The mother is now in her second trimester. The baby's kidneys have started producing urine, and the baby can make facial expressions. Despite the baby's eyelids being shut they can see light outside the womb. The baby's sex can be determined between 16 and 20 weeks. -
Week 17-20
If the baby hasn't started moving yet they will within a few weeks. The baby can hear the mothers heartbeat and the voices around. Their skin is wrinkly and covered in a protective waxy coating. -
Week 21-27
The baby can feel the mother move, and their sense of hearing continues to improve. Their taste buds are developing, as well as hair on the head. Their brain is also developing more and more. They are almost a foot long and weighs just over a pound. Their lungs are growing but won't be fully functional for a few more weeks. -
Week 28-34
The mother has now entered her third trimester. They have eyelashes and their eyesight is improving. Billions of neurons are developing in their brain. They now have fingernails and toenails. They are also beginning to gain more weight in preparation for birth. The lungs and central nervous system are continuing to develop. Their skin is soft and smooth. -
Week 37-42
By the 37th week the baby is considered 'early term', by the 39th week they are 'full-term' and considered ready for life outside the womb. By week 41 you are past your due date and considered 'late term', by 42 weeks you are 'post term' they baby health may have to be monitored with tests such as 'non-stresstest' or 'biophysical profile'.