Week 4 of Pregnancy
Choose Your Week
- Your 1st Week
- Week 2 of Pregnancy
- Week 3 of Pregnancy
- Week 4 of Pregnancy
- Week 5 of Pregnancy
- Week 6 of Pregnancy
- Week 7 of Pregnancy
- Week 8 of Pregnancy
- Week 9 of Pregnancy
- Week 10 of Pregnancy
- Week 11 of Pregnancy
- Week 12 of Pregnancy
- Week 13 of Pregnancy
- Week 14 of Pregnancy
- Week 15 of Pregnancy
- Week 16 of Pregnancy
- Week 17 of Pregnancy
- Week 18 of Pregnancy
- Week 19 of Pregnancy
- Week 20 of Pregnancy
- Week 21 of Pregnancy
- Week 22 of Pregnancy
- Week 23 of Pregnancy
- Week 24 of Pregnancy
- Week 25 of Pregnancy
- Week 26 of Pregnancy
- Week 27 of Pregnancy
- Week 28 of Pregnancy
- Week 29 of Pregnancy
- Week 30 of Pregnancy
- Week 31 of Pregnancy
- Week 32 of Pregnancy
- Week 33 of Pregnancy
- Week 34 of Pregnancy
- Week 35 of Pregnancy
- Week 36 of Pregnancy
- Week 37 of Pregnancy
- Week 38 of Pregnancy
- Week 39 of Pregnancy
- Week 40 of Pregnancy
First Trimester
Implanted embryo
1. The uterine lining secretes hormones that help to support the pregnancy.
2. Chorionic cavity
3. The yolk sac is forming. It will nourish the embryo until the placenta starts functioning and make blood cells until the liver can do this.
4. The placenta starts to develop here. Soon the cells will penetrate the lining of the uterus.
5. The embryo consists of just two layers of cells that will divide very rapidly to form the beginnings of the baby's body.
6. The amniotic cavity, which later becomes the fluid-filled amniotic sac that protects the baby, develops from this area.
The embryo-to-be, now securely implanted in the lining of your uterus, is starting to develop. Although you could do a home pregnancy test this week, you may end up disappointed or uncertain because at this stage a definite result is unlikely. It can be nerve racking, wondering if an unwanted period is about to arrive and dash your hopes. Talk to your partner and share your feelings with him-he may be anxious, too.
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 embryo, now less than 0.5 mm long. read more
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. read more
You are 3 Weeks and 3 Days Pregnant
Your baby todayThe embryo is implanted and is 10 days old. The entry point at which the embryo buried into the lining of the uterus is now covered by a clot, and this prevents blood loss and protects the embryo. read more
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 helps the lining thicken. read more
You are 3 Weeks and 5 Days Pregnant
Your baby todayThe first stage of placental development-your baby's life support system-is shown here. The image shows nuclei (blue) within a continuous network of cells that will become the placental villi. At first the tiny villi are solid; later, they will contain blood vessels. read more
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 area below. read more
