Pregnancy Weeks 1-4

Congratulations! YOU ARE PREGNANT!  One of the most exciting periods of your life waits ahead of you, promising great changes. You have something to think about, and you will want to do a lot to prepare for the birth of your child. Here is an introduction on how your body and baby are developing in the first month, thus, weeks 1-4 of your pregnancy.

A New Life Awaits

All the time – while you work, take a walk, relax, or sleep – a miracle is taking place inside of you.

However, you may still not feel you’re pregnant yet. Perhaps your emotions or physical sensations are just beginning to appear. You may have been looking forward to your pregnancy and only just happily caught the symptoms that your body gave you (after a missed period).

You may already feel mild nausea, frequent hunger, thirst, fatigue, fever, weakness, or dizziness.

This news may have taken you a little by surprise. Perhaps you thought at first that you just caught a cold. It may be that you simply “knew” that you were pregnant, even before the appearance of any signs.

However, whatever the physical symptoms, you will probably need to get used to the fact that you’re pregnant- even if this child was planned in advance.

No matter where you hear the news — whether at the doctor’s office or at home after a pregnancy test, you may experience joy, fear, relief, mistrust, confusion, or all the feelings mentioned above.

Of course, your first reaction will largely depend on whether the pregnancy is a surprise for you or is the result of many months of hopes and expectations.

Don’t be surprised that it can take some time for you to become aware of the fact that you’re pregnant.

This is what can expect in the first four weeks ahead of you.



First Week of Pregnancy

The ovum meets the sperm and fertilization occurs.

As soon as the sperm penetrates the egg, fertilization takes place; this usually happens at the top of one of the fallopian tubes.  From the outset, the fertilized egg contains a complete genetic set: twenty-three chromosomes from the mother and twenty-three chromosomes from the father. At the time of fertilization, the sex of the unborn child is determined.

Sometimes two ovules fertilize with two sperm, which leads to the birth of twins. More rarely, one sperm fertilizes one egg and divides the egg into two parts, resulting in identical twins.

Then, during the four-day trip along the fallopian tube a distance of 10 cm (4 inches), the fertilized egg cell keeps dividing. By the time this unborn baby reaches the uterus, it consists of at least sixteen cells.

In the first eight weeks of their life, these cells are called “embryos,” but most mothers prefer the term “baby.”




Second Week of Pregnancy


On the seventh day, an embryo resembling a microscopic raspberry, finds a suitable place and implants in the uterine mucosa, usually in the upper third part or closer to the top of its new home. Likewise, the embryo embeds in the mucous membrane penetrated by blood vessels, it releases a few drops of blood, which you may observe as “spotting”.

This growing sprout of a new life, which has received the name “blastocyst”, begins to organize into groups of cells, each of which are several hundreds. Some of these cells strengthen in the mucous membrane of the uterus. Others form groups, each of which has its own destiny.

The uterus, in response to the presence of the embryo, begins to form the placenta germ, which transfers nutrients from the mother’s blood to the developing baby and removes the waste products of the fetus. As it develops, the placenta begins to produce the hormone ChCHG (human chorionic gonadotropin). This strengthens the uterine lining and stimulates the growth of the embryo, whilst maintaining high levels of estrogen and progesterone.

With the development of the placenta, CHHG enters the mother’s bloodstream. By the end of the second week, when carrying out a pregnancy test, this hormone can be detected in the mother’s urine.



Third Week of Pregnancy

The placenta and baby grow, the level of hormones increases.

By this time, you will have missed your period. A woman may suspect that she is pregnant. The rising level of hormones in the blood can confirm her suspicions. Pregnancy hormones block ovarian ovulation, and the ovaries with hormones signal the brain’s pituitary gland to no longer stimulate menstruation.

In the third week, a single cell transforms into several millions of cells. The cells begin to differentiate into three types: cells that turn into the nervous system, skin, and hair; cells that form the gastrointestinal tract; and cells that give rise to the circulatory system, urogenital system and the musculoskeletal system. By the end of the third week, a rudimentary heart, shaped like a tube, begins to beat in the fetus, and blood begins to circulate.




Fourth Week of Pregnancy

The baby takes shape.

During this week, the child grows to the size of a rice grain and takes a curved shape. The umbilical cord with three separate blood vessels appears.

On the outer boundary of the baby’s tiny body, a spinal tissue forms. Also, tiny limbs portrude from the body, which will later turn into arms and legs.

The heart, which looks like a ball, is divided into two halves. It begins to pump blood into almost formed main blood vessels. Specialized ultrasound machines even allow you to observe a regular heartbeat.

The small specks on the child’s head indicate where the eyes will form. The hemispheres of the brain and the anlage of the child’s spinal cord develop. Similarily, organs such as the trachea, esophagus, stomach, brain, mouth, liver, gall bladder, thyroid and bladder begin to develop.

Surprisingly, by the time the expectant mother comes to the doctor for the first examination, the main organs of the baby will have already formed.



In this post you read about what changes happen in your first month of pregnancy, weeks 1-4. So, what do you think? How have you been feeling?

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