Your First Four Weeks Of Pregnancy

It can be very confusing when you begin your own pregnancy calendar and it just doesn’t seem to coincide with what your doctor or midwife are telling you. The simple reason for this is that your due date, and therefore the start of your pregnancy, is usually calculated from the first day of your last menstrual cycle. This is what is referred to as the gestational age of your baby.

Working on this time line, most mothers to be don’t even know they are pregnant during the first four weeks. So when working out your pregnancy calender, a good place to start would be your menstrual cycle rather than fertilization or conception.

4 weeks of pregnancy

During your first week of pregnancy you are probably thinking about when you will be the most fertile to conceive and looking for signs of ovulation. If you have been trying to conceive for a while, don’t get stressed. You are less likely to conceive if you are worried – buy a fertility kit to help you predict ovulation.


During the second week your body begins to make small changes to be ready when conception takes place. This starts with the production of oestrogen which floods your uterus and results in the creation of a lining that is rich in blood to enable it to support a fertilised egg.

Ovulation normally takes place around 2 to 3 weeks after the first day of your menstrual cycle. A ripe egg or ova is released into the fallopian tubes from your ovaries. This egg is now ready for fertilization. There is no way of accurately predicting exactly when ovulation takes place so try to have sex as often as possible during this time when you are most fertile.


As you enter your 3rd week, the miracle of life has begun as sperm meets egg and fertilization has occurred. This new life is called a zygote and it immediately begins its journey along the fallopian tubes towards your womb or uterus. But this little miracle will stop for nothing and growth has already begun as the cells begin dividing and splitting along the way.

baby development 1-4 weeks

As this tiny ball of cell makes its way to the uterus, it changes its name once again and is now referred to as a blastocyst. This blastocyst is about the size of a grain of beach sand and attaches itself to the wall of the uterus as it continues to grow and multiply. This is conception!

By week four you are officially pregnant although you will probably not be able to tell. Even a pregnancy test at this early stage will probably give a negative result. But your body knows all about the new life that is growing inside you and you should begin to notice slight changes soon.

This tiny blastocyst is now ready for one final change when it splits into two distinct cell groups. The first group of cells create the placenta that will be your baby’s main source of nutrition through the coming 9 months. The second group of cells is the embryo (your baby) which is very specialized and organized into three main groups.

These three groups are each individually implanted with a blue print to create the cells that will form the different parts of the baby’s body. The ectoderm will create skin, hair, eyes as well as the nervous system. The mesoderm is responsible for the heart, kidneys, bones, muscles and sex organs. The endoderm will form the lungs, liver and digestive tract for your baby.

During this four week period you can start playing an active role in your pregnancy. You can begin taking pregnancy vitamins, folic acid and amino acids. These acids are considered to be the building blocks of life and can be beneficial to you even if you aren’t pregnant or trying to conceive.


You can also begin reading and finding out as much information as you can about what the next 9 months hold for you and your baby. Knowledge is power and the more you know about what you should expect, the more at peace you will be with the changes your body will be going through as well as your baby’s progress.

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