3 weeks pregnant, what happens to the fetus and what the woman feels

And then came the 3rd obstetric week of waiting for the baby. It is during this period that the fertilization of the egg takes place. This is a very important period, because right now the development of the fetus and the migration of the ovum begins, which will soon be fixed in the uterus.

The baby’s age is the first week, pregnancy is the third obstetric week (two full).

During this period, the egg is dividing, respectively – this week you may have twins, or even triplets. But the same period is dangerous because the egg can be implanted not in the uterus, and as a result, an ectopic pregnancy occurs.

The content of the article:

What does the term mean – 3 weeks?

It is worth understanding what is meant by “3 weeks”.

3rd obstetric week – this is the third week from the last menstruation. Those. this is the third week from the first day of the last menstrual period.

3rd week from conception – This is the 6th obstetric week.

3rd week from delay – This is the 8th obstetric week.

Signs of pregnancy in the 3rd obstetric week – 1st week of pregnancy

Most likely, you still do not know that you are pregnant. Although this is the most common period for a woman to find out about her situation. Signs of an interesting situation at this time have not yet been expressed.

Embryo at 3 weeks gestation
Embryo at the 3rd week of development

You may not notice any changes at all, or you may attribute them to the usual signs of PMS. These symptoms are typical – both for the first month of waiting for a baby, and for premenstrual syndrome:

  • Swelling of the breasts;
  • Drowsiness;
  • Lethargy;
  • Irritation;
  • Drawing pains in the lower abdomen;
  • Lack or increased appetite;
  • Dizziness.

The first week after conception is very important. It is during this time that the ovum travels through the fallopian tube into the uterus and is fixed on the wall of the uterus.

This week the risk of miscarriage is very high, because the female body does not always accept a foreign body that attaches to the wall of the uterus, especially when a woman has good immunity. But our body is cunning, it contributes to pregnancy in every possible way, so you may feel weak, unwell, the temperature may rise.

What happens in a woman’s body in the 3rd obstetric week?

As you know, between the 12th and 16th day of the menstrual cycle, a woman ovulates. This is the most favorable time for conception. However, fertilization can occur both before and after it.

However, the body of each expectant mother is individual. In some women, at 3 obstetric weeks, or the first week of pregnancy, there are still no signs, while in another, early toxicosis may begin.

In any case, at the beginning of the 3rd obstetric week, it makes no sense to buy a pregnancy test, a home analysis will not give an unambiguous answer to such an important question. If you have doubts, then you should visit a gynecologist. But during the period when the expected menstruation is delayed, at the end of the 3rd obstetric week, or the 1st week of pregnancy, a pregnancy test can show two stripes, confirming pregnancy.


During this period, a pregnancy test does not always show a reliable result – it can be either false negative or false positive.

As for the signs in the first week from conception, or the third obstetric week, as such, there are no pronounced signs of pregnancy. You may feel a little weakness, drowsiness, a feeling of heaviness in the lower abdomen, a change in mood. All of this is common in women during PMS.

But a clear sign can be implantation bleeding. However, not everyone has it, and if it does, then it may not be given due importance, it is often mistaken for the beginning of menstruation.

Reviews on forums

It is very important for this period to quit smoking and stop using alcohol and drugs. Now you have to become a “good mommy” and take care of yourself twice.

Naturally, it is necessary to notify the doctor if during this period you took medications that are prohibited for pregnant women.

In addition, it is very important during this period to take care of your physical condition. If you went to the gym before pregnancy, then it is worth reviewing the load and slightly reducing it. If you haven’t, then it’s time to take care of yourself. Just remember that now your position is not the time to set records.

Feedback from forums:


I have no sign. Only the test was “striped”. I checked it several times! On Monday I will go to the consultation, I want to confirm my assumptions.


I have been walking for the third day. It feels like I got the flu. Dizzy, nauseous, no appetite, no sleep. I do not know if this is pregnancy, but if so, then I am at 3 weeks.


Each girl has everything individually! For example, my symptoms appeared very early, for about 3 weeks. An exorbitant appetite appeared, she began to run to the toilet often and her chest was very full. And a few weeks later I found out that I was really pregnant.


I got nagging pains in the lower abdomen. The gynecologist prescribed special medications and vitamins. It seems like these sensations are the norm, but in my case it is the threat of miscarriage.


I am missing any symptoms. Until the expected monthly period, but the usual symptoms of PMS are also absent. Am I pregnant?

Fetal development in the 3rd week

Regardless of the outward signs or their absence, a new life is being born in your body.

  • At the 3rd week, the baby is determined by gender, but you will not know about it soon. When the embryo enters the uterus and attaches itself to its wall, it begins to develop rapidly.
  • During this period, the hormones of your unborn baby tell your body about their presence. Your hormones, in particular estrogen and progesterone begin to work actively… They prepare favorable conditions for your baby’s stay and development.
  • Your “baby” now does not look like a person at all, while this is only a set of cells, size 0.150 mm… But very soon, when it takes its place in your body, it will begin to grow and form at a tremendous rate.
  • After the embryo is implanted in the uterus, begins a joint experience. From this moment on, everything you do, drink or eat, take medication or play sports, even your addictions, you divide in two.

Video. First week from conception

Video: What’s going on?

Photo of the fetus in the first week of pregnancy
Photo of the embryo at the 1st week

Ultrasound in the 1st week

Photo ultrasound - 1 week of pregnancy
Photo ultrasound – 1 week

An ultrasound scan at the beginning of 1 week allows you to examine the dominant follicle, assess the thickness of the endothelium and predict how the pregnancy will develop.

Photo and video of the development of the embryo in the 3rd obstetric week

Photo of the embryo 3 weeks pregnant
Photo of the embryo in the 3rd week of pregnancy
Ultrasound in the 3rd week of pregnancy
Ultrasound in the 3rd week

Video: What Happens in Week 3?

Recommendations and advice for a woman

At this time, many gynecologists advise:

  1. Refrain from excessive physical exertion, which can cause menstruation, and, accordingly, termination of pregnancy;
  2. Control your emotions and avoid stressful situations;
  3. Review your diet and exclude junk food and drinks from it;
  4. Give up bad habits (smoking, alcohol, drugs);
  5. Refuse to take medications that are contraindicated for pregnant women;
  6. Start taking folic acid and vitamin E;
  7. Start moderate physical activity;
  8. To formalize a relationship with a future dad, while your position is still unknown to anyone and you can wear any dress.

Previous: Week 2
Next: Week 4

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What did you feel or feel in the 3rd week? Share your experience with us!

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