• empty egg follicle in the ovary
    Week 4 of Pregnancy
    You are 3 Weeks and 4 Days Pregnant
    Your baby todayTo embed itself in the lining of the uterus, the embryo-to-be needs the help of progesterone, secreted after ovulation by the empty egg follicle, the corpus luteum (shown in pink in this cross section of an ovary). Progesterone hel...
  • 3 Weeks 5 Days Pregnant Blastocyst
    Week 4 of Pregnancy
    You are 3 Weeks and 5 Days Pregnant
    Your baby todayThe ball of cells, known as the blastocyst, that will form the embryo has now completely embedded within the lining of the uterus and the lining has regenerated over it.Unfortunately, in the complex process of conception, only abou...
  • amniotic cavity of embedded blastocyst
    Week 4 of Pregnancy
    You are 3 Weeks and 6 Days Pregnant
    Your baby todayThis microscope view of an embedded blastocyst shows the amniotic cavity (semicircular white area at top), with the cells that will develop into the baby just below (dark oval at the 12 o'clock position). The yolk sac is the pink a...
  • cells of the embryo week 3 of pregnancy
    Week 4 of Pregnancy
    You are 3 Weeks and 1 Day Pregnant
    Your baby todayThis is a cross section of the ball of cells embedded in the uterus at this early stage of pregnancy. It contains fluid in the center and two areas of white cells with a darker streak of cells between them-these will form the embry...
  • cells of blastocyst embedded in uterus
    Week 4 of Pregnancy
    You are 3 Weeks and 2 Days Pregnant
    Your baby todayIn this computer-generated image the entire blastocyst can be seen embedded in the lining of the uterus. The cells that will develop into the embryo are seen as the dark area in the 12 o'clock position. ...