I am going to be a mother

By the end of this week, you can announce to the world that you are going to be a mother. Your period has not arrived when expected. Although occasional delays can occur, you are excited. Rather than remain uncertain, buy a pregnancy test and use it at home. If it is negative, do not immediately lose hope: pregnancy tests can sometimes be negative. The most sensible next step is to make an appointment with your doctor. If you do not yet have one, ask friends for recommendations.

It is unfortunate when a woman does not have a gynaecologist she sees regularly and can ask about her concerns. Your doctor will examine you. At this stage, the gestational sac generally cannot yet be seen on ultrasound. However, a blood pregnancy test can detect pregnancy with almost 100% accuracy. If you are pregnant, your doctor will give you advice.

If you are not pregnant or your period starts, try not to be too disappointed. Remember that the chance of pregnancy on the first attempt is only 25%. Keep trying. If your period is late but you are not pregnant, your doctor will prescribe treatment to bring on a period.

Pregnancy brings physical and emotional changes. At this stage, the symptoms are almost identical to premenstrual symptoms: weakness, fatigue and breast tenderness.

Let us look at what is happening inside. Implantation occurred about 1 week after fertilisation. Cells called trophoblasts damage endometrial cells, causing tiny pools of blood to form. These trigger the development of new vessels and the circulation of the future placenta. Meanwhile, the embryoblast cells multiply rapidly, forming a two-layered disc. The upper layer continues developing into the amniotic membrane and embryo, while the lower layer forms the yolk sac.

By the end of week 4, tissue called chorionic villi extends into the uterus, and blood vessels begin forming in the embryo. The yolk sac has started producing the cells that form the blood system. A connecting stalk now joins the embryo and placenta; it will later form the umbilical cord.

The appearance of a thin cell layer on the embryonic disc marks the beginning of gastrulation. At the end of this process, the embryo's three layers have formed: ectoderm, endoderm and mesoderm.