1. 3rd week of pregnancy - what happens in week 3 of pregnancy
2. How your baby develops in the 3rd week of pregnancy
3. How you feel in the 3rd week of pregnancy
4. What you should look out for in week 3 of pregnancy
5. Relax and wait for your little miracle

3rd week of pregnancy - what happens in week 3 of pregnancy

From this 3rd week of pregnancy, the actual pregnancy begins, even if you probably don't know anything about it yet. You ovulated towards the end of the second week of pregnancy. This small egg is now fertilised by a sperm and makes its way to the uterus, where it looks for a cosy place to implant. In this third part of our pregnancy calendar, you can find out what exactly is going on in your body in week 3 of pregnancy, how your baby develops in these first few days and what you should look out for.

How your baby develops in the 3rd week of pregnancy

Sure, you can't really talk about a baby in the third week of pregnancy. But this tiny cluster of cells will develop into a real little person over the next 37 weeks. Let's take a look inside your belly and see what's going on.

3rd week of pregnancy: Fertilisation is successful

Your ovulation takes place at the end of the 2nd week of pregnancy or at the beginning of the 3rd week. The tiny egg is released into the fallopian tube and makes its way towards the uterus. If you have intercourse during your fertile days, the egg now meets the sperm and fertilisation can occur. Although an average of 300 million sperm are released during ejaculation, in the end only one of them manages to penetrate the egg. The egg's membrane then closes so that no other sperm cell can enter. Finally, during fertilisation, the nuclei of the egg and sperm fuse together - a new life is born!

This tiny fertilised egg, which is invisible to the eye, now contains all the genetic information. This means that it is already clear whether your baby is a boy or a girl. Characteristics such as blood group, hair and eye colour are also determined by the chromosome sets inherited from you and your partner.

The fertilised egg cell continues to develop

The journey of the fertilised egg (also known as the zygote) through the fallopian tube takes around four days. The day after fertilisation, it begins to divide. One cell becomes two, then four, then eight. A small ball of cells, the morula, is formed. Once in the uterine cavity, it floats around freely for a while and continues to divide. It becomes a blastocyst around day 4 and by day 5 it already consists of a good 100 cells. Inside are the so-called embryoblasts, from which the embryo will develop. The outer cells, the trophoblasts, later develop into the placenta and amniotic sac.

Implantation occurs

Around five to six days after fertilisation, the blastocyst nests in the protective mucous membrane of your uterus. It forms a delicate mesh with which it penetrates the lining of the uterus and thus establishes a connection to the mother's bloodstream as the pregnancy progresses. The blastocyst now begins to produce the hormone HCG. This stimulates the corpus luteum in the ovary to produce progesterone, which is important for maintaining the pregnancy. This corpus luteum was formed from the follicle after ovulation.

How you feel in the 3rd week of pregnancy

Did it work or not? Perhaps you are already very impatient in this third week of pregnancy. Your ovulation has passed and you would love to know whether fertilisation has taken place, whether a little person is already growing inside you. However, you will have to be patient a little longer.

Practical help for you:
Emergency service midwife Katharina explains the most important things about the maternity pass online.

What signs do you have in week 3 of pregnancy?

Are symptoms such as nausea or breast tenderness already noticeable in the 3rd week of pregnancy? The answer is no. In this early phase of pregnancy, women usually do not yet have any of these typical signs.

However, some pregnant women notice light bleeding in week 3 of pregnancy. This has nothing to do with menstrual bleeding, but is what is known as implantation haemorrhage. At the moment when the blastocyst implants itself in the well-perfused uterine lining and the foetal tissue connects with the maternal tissue, fine blood vessels can open, resulting in a light, usually bright red haemorrhage. Sometimes the amount of blood is so minimal that the woman does not even notice it. This implantation haemorrhage is absolutely nothing to worry about, but can be seen as the first sign of pregnancy.

Some women feel a slight pulling sensation in the lower abdomen in the 3rd week of pregnancy, which is often described as implantation or nidation pain. This pulling or pricking sensation in the area of the uterus is also due to the implantation of the blastocyst in the uterine lining.

If you usually measure your basal body temperature to determine your fertile days, you will see that it has risen by a few tenths around the day of ovulation. This increased temperature level is maintained in the 3rd week of pregnancy by the hormone progesterone and, in the event of pregnancy, remains in place for the next few weeks. If there is no implantation, the temperature will fall again at the end of the 4th week of the cycle.

Your cervical mucus, which was clear and fluid on the fertile days, also becomes less, thicker and stickier again. It now seals the entrance to the cervix like a plug to protect the embryo from rising germs and bacteria.

Is a pregnancy test already possible?

Are you already impatient and can't wait to find out if you're pregnant? That's completely understandable. However, a pregnancy test in the 3rd week of pregnancy does not yet provide a meaningful result. Although the tests are becoming increasingly sensitive, it is clearly still too early for this. The fertilised egg must first reach the uterus and successfully implant before it can start producing the pregnancy hormone HCG. Try not to put yourself under pressure and wait until your period has stopped before testing.

What can be seen on the ultrasound?

An ultrasound also makes no sense in the 3rd week of pregnancy. Your gynaecologist would only recognise a highly developed uterine lining. The blastocyst measures only a fraction of a millimetre and therefore cannot be detected by ultrasound. In addition unnecessary ultrasounds should be avoided as much as possible during pregnancy. It is better to wait until you are at least 5 or 6 weeks pregnant to see your gynaecologist.

What you should look out for in week 3 of pregnancy

Pregnant or not? Even if you don't have an answer to this question in the 3rd week of pregnancy, you should consider the following things now to be on the safe side:

Give up alcohol and nicotine now at the latest

It is recommended that you give up alcohol and cigarettes as soon as you stop using contraception. If you haven't managed to do this yet, now is the time. At the very latest when you have a positive pregnancy test in your hand, you should stop consumption completely. Both addictive substances can harm your unborn child.

Did you drink alcohol in the 3rd week of pregnancy when you had no idea you were pregnant and are now worried afterwards whether you have harmed your baby? Then I can reassure you. In the 3rd week of pregnancy, your embryo is not yet connected to your bloodstream and is therefore not exposed to any harmful substances. In addition, the all-or-nothing principle applies in the first three to four weeks of pregnancy. If an egg cell is damaged in this early phase, it stops dividing. There is no implantation at all and it dies. These extremely early miscarriages usually go unnoticed and end in normal menstrual bleeding. So if some time has passed since you consumed alcohol and you have a positive pregnancy test in your hand, you can assume that your baby is doing well. However, if you are planning a pregnancy, giving up alcohol and nicotine will help you a lot. After all, the all-or-nothing principle should be everything to you: A little baby in your arms in just a few weeks.

Make sure you eat a healthy diet

The 40-week pregnancy will demand a lot from your body, as it has to look after two people from now on. For this reason, make sure you provide it with healthy nutrients, vitamins and trace elements. Adequate hydration is also important. So drink at least 2.5 litres a day. Still water and unsweetened herbal teas are ideal.

Important: take folic acid

During pregnancy, your folic acid requirement increases by 100 per cent. Your baby urgently needs this B vitamin for the development of its nervous system. For this reason, it is recommended that you take it before you become pregnant, 400 micrograms of folic acid per day . You should start now at the latest.

Caution when taking medication

Do you have to take medication regularly? Then please contact your doctor to make sure that they do not pose a risk to your unborn child. In some cases, it may be possible to switch to another, better tolerated active ingredient.

Relax and wait for your little miracle

In this third week of pregnancy, incredible things are happening in your womb behind the scenes. The fertilised egg develops into an embryo with over 100 cells. It finds a protective nest in your uterine lining, where it will develop into a little human being over the coming months. You cannot yet know whether you are really pregnant. Try to be patient and experience this 3rd week of pregnancy in a relaxed and conscious way. It will only be another week before you can take a pregnancy test. If this is finally positive, you will find in our Online workshop for the 1st trimester Answers to all your questions.