3 Weeks Pregnant: Embryo (Fetus) and Symptoms

In Week 3 of pregnancy, the blastocyst (the second stage of a fertilized egg) implants itself in the endometrium (lining of the uterus), and pregnancy is established. After the egg implants itself, the levels of hormones inside the womb change abruptly, and some women will start noticing symptoms of pregnancy. So, what are the physical changes in the pregnant mom and embryo (which will be called a fetus starting from the end of Week 10 of pregnancy)?

3 Weeks Pregnant: What is happening inside my belly?

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In Week 2, the blastocyst implants itself into the endometrium, which has thickened in order to receive it. As the blastocyst moves towards the womb, it causes the villi (branched structures that grow from the amniotic sac) to grow and they in turn break down the lining inside the womb so as to allow the blastocyst to implant itself deep into the lining.

When the blastocyst enters the womb, the nutrients and oxygen needed for the blastocyst’s growth are derived from the mother’s blood vessels. This process is called “implantation,” and medically speaking, it means that the pregnancy is established. When the pregnancy is established, the baby is called an “embryo” and the initial environment needed for the embryo to grow is slowly being created.

3 Weeks Pregnant: Pregnancy test kits

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When the blastocyst implants itself into the endometrium, the villi produce a hormone called hCG (human chorionic gonadotropin). The hCG stops the next period or ovulation from taking place. The endometrium thickens and changes in order to be able to support the pregnancy. The hCG is secreted into the bloodstream, and this triggers the secretion of huge amounts of estrogen and progesterone.

The majority of pregnancy test kits react to a hCG level of 50mIU/ml. In Week 3 of pregnancy, only a little hCG is secreted, and so pregnancy test kits do not react and pregnancy cannot be confirmed in most cases. Signs of pregnancy appear in Week 4 at the earliest, and majority of women can able to detect their own pregnancy one week after the expected date of one’s period or later, when pregnancy is around Week 5 to 6.

3 Weeks Pregnant: Detectable symptoms?

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For some, symptoms that suggest the possibility of pregnancy start appearing in Week 3 at the earliest. Those symptoms are called “very early signs of pregnancy,” and refer to the changes starting from one’s expected period date to Month 2 of pregnancy. If you feel any discomfort or detect the following symptoms, it might just mean that you’re pregnant.

Examples of very early signs of pregnancy

● Slight bleeding (vaginal spotting)
● Breast pain and tightness
● Lethargy and sleepiness
● Gustatory (taste), olfactory (smell) senses change
● Your basal body temperature continues to rise
● You are reduced to tears easily

3 Weeks Pregnant: Implantation bleeding and pain

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The slight bleeding arising from implantation is a result of the villi breaking down the uterine wall when the blastocyst implants itself in the endometrium. The blood looks like vaginal discharge and it can be light brown, light pink to light red in color. In many cases, implantation bleeding is less than menstrual period bleeding and only lasts for 1 to 2 days. About 10 to 20% of pregnant women experience implantation bleeding.

You may have heard of a similar symptom of pregnancy called “implantation cramping,” which refers to the pain experienced when implantation takes place. However, there is no medical proof for whether this claim is true or not.

Some people believe that the pain arising from ovulation cramps has been wrongly attributed to “implantation cramping”. The period when these “cramps” occur, the duration and the level of pain experienced differs from person to person.

3 Weeks Pregnant: Embryo (Fetus) is around 0.1 mm long

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As the embryo is around 0.1 mm and is very small, it cannot be detected through ultrasound scans. In Week 3, the baby is still called an “embryo”. Roundish in shape, the embryo does not look like a human yet, but will change into a oval shape as pregnancy nears Week 4. The villi begin to form the placenta.

3 Weeks Pregnant: Stop drinking and smoking

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Consuming alcohol or tobacco causes the blood vessels to constrict, reducing the flow of sufficient nutrients sent to the uterus. As a result, a healthy womb environment cannot be sustained and this increases the risk of deformity, premature birth and miscarriage increases.

Even if pregnant mothers themselves do not smoke, they may be subject to passive smoking if their partners smoke tobacco, and this in turn affects the baby. At Week 3, although there are no detectable signs of pregnancy, once you suspect you are pregnant, it would do Baby much good if you stop smoking and drinking.

3 Weeks Pregnant: Getting ready for Baby

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When you are 3 weeks pregnant, the cells of the embryo in you become one with your body. Your womb prepares itself to receive your developing baby, who will call the womb home for the next 9 months. Once you suspect that you are pregnant, try to pay more attention to your physical condition and health. Also, if you learn a little more about the changes arising in your own body, it could help put your mind at ease.

Pregnancy can be overwhelming, especially for first-time mothers-to-be. If you arm yourself with knowledge about what to expect, you’ll feel more relaxed and confident while you wait for your baby to arrive.