Week 3-4: February 12th- 25th

My baby is the size of a poppy seed. In week 3, sperm meets egg, and voila: conception! Your little zygote sets off on a six-day trek through your fallopian tubes, dividing and redividing into identical cells as it travels to your uterus.
In week 4, now safe in your womb, the ball of cells (blastocyst) splits in two, becoming the embryo and the placenta. The amniotic sac and fluid are forming around baby, and will act as a cushion for the next eight months.