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Development Before Birth: The First Trimester
Congratulations, you’re pregnant! What an exciting time it is for you and, like many new mothers, it may be a little daunting too. You will probably have lots of questions about the changes that are going to happen in your body over the next nine months. Your health advisor or GP will have given you lots of information and advice, but are some of the developments you can expect in the first trimester:

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Week One:

The miraculous mument of your baby’s conception results from two special cells, called gametes, combining to form the first cell of a new individual. When they combine the new cell, called the zygote, has 46 chromosomes, which is what you have and so do the majority of humans in the rest of the world. In the following week, the zygote moves into the womb and multiplies to form a collection of cells called the blastocyst. If you are expecting twins it’s most likely that they would have developed from two fertilised ova but, at this point, the blastocyst sometimes divides into two and two babies develop, or identical twins.

Weeks 2-4:

By the following week the blastocyst has settled down deep into the lining of the womb and the amazing structures that will feed and protect your developing baby throughout pregnancy begin to form.

By three to four weeks the embryo is ¼ inch long. It has developed a primitive brain and spinal chord, and it’s heart, muscles, backbone, ribs and digestive tract have started to develop, although it’s not yet developed into a boy or a girl.

Weeks 5-8:

By 5-8 weeks into your pregnancy, the foetus will be about an inch long and the face, arms, legs, toes and fingers have begun to form, as well as the creation of other internal organs. It is at this stage that the sex of your baby will be determined.

Your baby’s sense of touch then begins to develop which is especially sensitive around the mouth and the soles of the feet, and she starts to move. Her excitatory mechanisms, that relate to ’switching on’ and starting, develop faster than her inhibitory mechanisms, or ’stopping’ function. This means she will be much better at starting to move around than stopping and this is a tendency that will continue into her early childhood.

Weeks 9-12:

At this age the embryo matures into what is called a foetus. She will be about 3 inches long and her genitals will have formed. When you visit your doctor now he will be able to hear your baby’s heartbeat using a stethoscope. As her nervous system, organs and muscles become more developed she can kick, suck her thumb, open her mouth and practice breathing. Interestingly, the thumb that she sucks at this age suggests her handedness is established, that is whether she will be right-handed or left-handed. She can also bend her arms, curl her toes and make a fist, and she will develop fingernails and tooth buds. Even though her eyelids will start to open and close during this period she doesn’t have an awareness of the world around her. She will act and react to stimulus but she isn’t able to think about what is or has happened to her and won’t be able to do this until she’s more than six months old.

How You Can Help:

* Enjoy being pregnant! But make sure you take all the advice provided to you by your health advisor or GP. They will advise you of the best way to take care of yourself to stay healthy.