The fertilized egg has completed its 7 to 10 day journey towards the uterine lining (endometrium) in which it settles comfortably. The fertilized cell was segmented throughout its journey in the fallopian tube and is now called a blastocyst. Under the action of hormones produced by your ovaries (progesterone), the endometrium thickens and starts the structural development of the maternal and fetal placenta and embryonic membranes.
A small peduncle (embryonic pedicle) appears and will lengthen to become the umbilical cord. Since the placenta is not yet ready to play its nourishing role, the yolk sac, a small cavity formed in the blastocyst around the 8th or 9th day after conception, will feed your baby in the meantime. In summary, the habitat of your little one is growing faster than you can imagine.

This week 

Baby measures about 0.2 mm (from head to heel)
Baby weighs about – no available data