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The first trimester of pregnancy is marked by an invisible, yet amazing transformation. Your body is going through enormous changes as it accommodates a growing foetus. A grand adventure is about to begin.

The weeks following conception, your uterus begins to support the growth of the placenta and the foetus. You will experience a significant increase of hormone levels that can accompany some of the pregnancy symptoms such as fatigue or morning sickness. Some odours may be more bothersome now and provoke queasiness.

While the road to motherhood can be bumpy at times, there are few pieces of advice women can take to make it a positive experience.

First, exercise can help to boost your energy, relax better at the end of the day, and can make sure your body is fit and healthy for when the time for childbirth comes. Exercise increases circulation, which ensures a healthy blood flow to the fetus and placenta. Endorphins released during workout are particularly helpful when you are experiencing hormonal changes. Low impact exercises, walking, stationary biking, swimming, yoga and Pilates are also good options.

The American College of Obstetricians and Gynecologists recommends that pregnant women exercise for at least 30 minutes per day, several days a week.

Secondly, it is essential to maintain a healthy diet, including adding an adequate amount of folic acid and other supplements as recommended by your doctor in order to help prevent neural tube defects such as spina bifida, anaemias and other possible complications.

Minimize your consumption of caffeine and diet sodas, and avoid alcohol all together. Cut out raw meats, unpasteurized foods and raw eggs due to a higher risk of infection. Fish is great for you thanks to Omega 3, but some is not because of high mercury levels found in fish meat. Your obstetrician can help you decide which is best.

The question of how much weight gain is healthy depends upon your pre-pregnancy weight. The Institute of Medicine recommends average weight women gain 11 to 15 kg during pregnancy, underweight women gain 12 to 18 kg and overweight women gain 7 to 11 kg.

There are eight different components that make up the total weight gain of pregnancy: the baby, the uterus, the placenta, the amniotic fluid, breasts, increased maternal blood, maternal reserves (fat protein) and tissue fluids (water retention). Weight gain is healthy, normal and essential during pregnancy.

This period is vital for the development of your baby. The foetus will maturate all of its organs by the end of the third month.

Your baby

 In the first 4 weeks of early pregnancy, the embryo is attached to a tiny yolk sac which provides nourishment. Subsequently, the placenta will be fully formed and will take over the transfer of nutrients to the embryo.

The embryo is surrounded by fluid inside the amniotic sac. It is the outer layer of this sac that develops into the placenta.
Cells from the placenta grow deep into the lining of the womb, establishing a rich blood supply so the baby receives all the oxygen and nutrients it needs.

The fifth week of pregnancy is the time of the first missed period, when most women realize they may be pregnant.

It is the beginning of the embryonic period. The embryo’s cells multiply and start to take on specific functions; this is called differentiation.

The embryo is now made of three layers called germ layers.

The top layer, the ectoderm, will give rise to the baby’s outermost layer of skin, central and peripheral nervous systems, eyes, inner ears and many connective tissues.
Your baby’s heart and  circulatory system will form in the middle layer of cells, the mesoderm. This layer of cells will also serve as the foundation for your baby’s bones, muscles, kidneys and much of the reproductive system.

The inner layer of cells, the endoderm will become a simple tube lined with mucous membranes. Your baby’s lungs, intestines and bladder will develop here.

While these organs are evolving, the heart is forming as a simple tube- like structure. Your baby already has some of its own blood vessels and blood begins to circulate. A string of these blood vessels connects your baby to you and will become the umbilical cord.

During week 6 growth is rapid. The neural tube along your baby’s back is closing and your baby’s heart begins dividing into four chambers and pumps blood.

Basic facial features will start to appear, including the eyes, nose, jaw, cheeks and chin. Your baby’s body is taking a C shaped curvature and small buds will soon become arms and legs.

Muscle and bone tissues are already building up and at this stage, the heart can sometimes be seen beating on an ultrasound scan.

By week seven, the embryo has grown to about 10mm long from head to bottom, also known as “Crown to Rump Length” (CRL). Your baby’s brain and facial features are rapidly developing, faster than the rest of the body.

Tiny nostrils become visible and the eye lenses begin to form. The arm buds get longer and the ends flatten out, these will become the hands. The inner ear starts to develop, but the outer ear in the side of the head won’t appear for a couple more weeks.
Nerve cells continue to multiply and develop as the nervous system starts to take shape.

There are usually early pregnancy classes that are available for you and your partner. This can help make the transition to pregnancy more real for your partner and give you both some idea of what is to come.

By the time you are 8 weeks pregnant, the baby is called a foetus, which means “offspring”. The arms are growing longer and fingers have begun to form although they have not separated yet. The different parts of the leg are still not properly distinct, it will be a little longer before the knees, ankles, thighs and toes develop.

The shell-shaped parts of your baby’s ears, are also forming and the eyes are becoming visible. The upper lip and nose have formed and the trunk of your baby’s body is beginning to straighten.
The foetus is still in its amniotic sac and the placenta is continuing to develop, forming structures called chorionic villi that help in the exchange of nutrients and materials between the placenta and the womb. At this stage, the foetus still gets its nourishment from the yolk sac.

In the 9th week of pregnancy, your baby’s arms grow, develop bones and bend at the elbows. Toes form and your baby’s eyelids and ears continue developing. The face is slowly forming. The eyes are bigger and more obvious and have some colour (pigment) in them.

By the 10th week of pregnancy, your baby’s head has become more round. The neck begins to develop and your baby’s eyelids begin to close to protect his or her developing eyes. The ears are starting to develop on the sides of your baby’s head, and inside the head its ear canals are forming. If you could look at your baby’s face you would be able to see its upper lip and two tiny nostrils in the nose. The jawbones are developing and already contain all the future milk teeth. The heart is now fully-formed. It beats 180 times a minute, that’s two to three times faster than your own heart.

At week 11 the foetus grows quickly and the placenta is rapidly developing (it will be fully formed at about 12 weeks). The bones of the face are formed now. The eyelids now cover the eyes, and will remain shut until the seventh month to protect the delicate optical nerve fibers. The ear buds look more like ears as they grow. Your baby’s head makes up one-third of its length, but the body is straightening fast and the fingers and toes are separating.

The brain is growing rapidly and producing more than 250,000 nerve cells a minute.

Just 12 weeks after your last period, the foetus is fully formed. All its organs, muscles, limbs and bones are in place, and the sex organs are well developed. From now on it has to grow and mature.

Your baby has a chin, a nose and a facial profile. The hair is on the head and the fingers and toes have developed soft nails. Vocal chords are complete. The brain is fully formed. The kidneys are developed and begin to secrete urine. Your baby has its reflexes; he may even suck his thumb.

From week 12 you may be able to hear the baby’s heart beat through a Doppler monitor on your tummy at the prenatal visit.

If you haven’t seen your midwife yet, contact your doctor or maternity team to book your appointment and to start your antenatal care.

New genetic technologies now allow for early testing. From the 10th week of pregnancy (and 12th for twin pregnancies), it is possible to analyze with high reliability the cell-free fetal DNA in the mother’s bloodstream for the early detection of chromosomal disorders including Down syndrome.

For further information, please check our product page to know how to perform Tranquility, Genoma’s cell-free fetal screening test and avoid the risk of amniocentesis.