Five weeks. The embryo is approximately 9mm long. A face develops, with openings for the mouth, the nostrils and eyes. In 1965, Swiss photographer Lennart Nilsson took a series of pictures of developing embryos which were published on Life magazine. Within days, the entire print run of eight million had sold out. Those remarkable pictures have been collected in a large hardcover book, "A Child Is Born," according to reports of British newspaper Telegraph.
Eight weeks. The rapidly-growing embryo is well protected in the foetal sac.
10 weeks. The eyelids are semi-shut. They will close completely in a few days.
16 weeks. The foetus uses its hands to explore its own body and its surroundings.
The foetus can now grab and pull the long umbilical cord. The skeleton consists mainly of flexible cartridge. A network of blood vessels is visible through the thin skin.
18 weeks: Approximately 14cm. The foetus can now perceive sounds from the outside world.
20 weeks. Approximately 20cm. Woolly hair, known as lanugo, covers the entire head.