How is there a baby before the heart starts beating?

Nurturing embryos: The womb prepares for the fertilized egg with a great layer of nutrient filled tissue that envelops the implanted egg.As the egg divides into a larger and larger embryo, nutrients pass through the tissue walls to feed the process.At a little over 3 weeks a crude tube is pushing nutrients along within an embryo about 2 mm long.The rest takes time and info from the dna but the process does get done.