Weeks 4-5
Between weeks 4-5 the embryo will be roughly 5mm in length and its heart will begin to beat. Limbs will also begin to develop at this stage, just appearing as bumps growing from it. For these first few weeks after conception, the embryo will be gaining nourishment from a tiny yolk sac which it is attached to. This stage, is when the first period will be missed. It 's at this point that women may begin to find out that they 're pregnant, however the pregnancy will be further along than they may think. The embryos nervous system will already be …show more content…
At 22 weeks vernix caseosa will begin to form. This is a white protective film that is greasy. By this point the foetus will also be covered in fine hair called lanugo. The foetus will begin to hear sounds from outside of their mothers body. Their eyes will also start becoming sensitive to light. The foetus ' body will begin to grow bigger, equalling out the proportion to its head. The foetus will now be heavier than the previously heavier placenta. The unborn baby, will begin to develop a pattern of sleeping and waking up. Although it 's lungs will not be working properly yet, The foetus will be practising breathing