At approximately day 1

Kidneys begin to function, producing urine.

Duration: 1 week

Reference

Moore KL, Persaud TVN. 1998. The Developing Human: Clinically Oriented Embryology. 6th ed. Philadelphia: WB Saunders Co.

At approximately day 1

Normal fetal weight: 8 gm

Reference

Moore KL, Persaud TVN. 1998. The Developing Human: Clinically Oriented Embryology. 6th ed. Philadelphia: WB Saunders Co.