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    What Changes Should I Expect in my Body During my Pregnancy?

    • 1st Trimester

      Once the embryo is implanted in the uterine cavity a number of changes occur in order to support the pregnancy and ensure normal fetal growth. These changes are associated with the function of reproductive hormones that act not only in the uterus but also in other body organs like the breast. Hormones also influence not only the anatomy but also the psychological state of the woman.


      Oestrogens and progesterone are normally produced by the ovaries but during pregnancy a large amount is also produced by the placenta. The function of these hormones is adjusted to the pregnancy needs and is responsible for many adverse effects such as morning sickness and constipation.

      Hormones affect the pregnant woman in many other ways,such as bycausing sudden mood changes or dislike for certain foods or smells. As the pregnancy progresses a hormonal balance is reached and the side effects subside.


      Breast enlargement due to oestrogens might be the first significant change you notice in your body. Breasts can also become very sore especially when touched. The nipplesbecome darker and increase in diameter.


      The uterus is the organ that shows the most obvious changes during pregnancy. However, its size does not change significantly during the first trimester. Changes are mainly qualitative i.e. increase in its blood supply and changes in the uterine wall.

      The cervix becomes gradually softer and under the influence of progesterone it secretes a protective mucous that becomes thicker and non-permeable during pregnancy. This thick mucus creates a protective layer for the uterus and the fetus against infections (does not allow the entrance of pathogens).

      Heart and circulation

      The changes in the cardiovascular system during pregnancy are significant because of the increase in the oxygen needs. The blood volume (plasma and red blood cells) increases as early as the 1st trimester and continues to gradually increase in order to support the fetus through the placenta. The heart size increases almost 10%. Due to these changes there is a drop in the maternal haemoglobin levels, therefore the doctor would recommend that you start iron supplements.


      Pregnancy increases your oxygen demands and your respiratory rate in order to support the fetus. Your metabolism also increased (10-15%).

      Until the end of the 1st trimester you might feel exhausted both physically and mentally. This is due to the changes that occur in your body in order to support the pregnancy and the normal fetal growth. You will feel better soon! The 2nd trimester is usually the least demanding.

    • 2nd Trimester


      At the beginning of the 2nd trimester your body is adjusted to the pregnancy changes. You do not suffer from sickness anymore, you feel much better physically (you do not feel sick) and you have more energy. You will feel your baby moving for the first time soon. The second trimester is considered the least stressful period of the pregnancy.


      The nipples become even darker, the veins more apparent and you will start secreting the colostrum (first milk) under the influence of the hormone prolactin. The colostrum is a fluid with thin consistency and rich in nutrients that will feed your baby during the first 3 days of life and until the normal production of milk. Not all women excrete colostrum. For some it gets secreted only after birth. As the pregnancy progresses you are getting ready for breastfeeding and your breast becomes heavier.


      During the 2nd trimester the uterus starts to increase in size and takes more and more space in the abdominal cavity (from the pelvis upwards). As the uterus gets bigger you will start feeling stretching of the lateral abdominal sidewall.


      The pelvic muscles and ligaments relax under the influence of progesterone in order to create more space for the uterus and the developing fetus. You might experience backache. The relaxation of the joints and ligaments is more obvious during the end of pregnancy and aims to increase the diameter of the pelvis in order to facilitate labour.

      You will also start walking like pregnant women do and adopt a different body posture. As the uterus puts pressure in the anterior abdominal wall, the pregnant woman leans backwards in order to balance. For this reason we observe a spinal lordosis.

      Gastrointestinal system

      Progesterone causes delay of the food passage in the small intestine in order for increased absorption of the nutrients. In addition, there is increased fluid absorption in the large intestine. These changes cause constipation.

      There is also relaxation of the sphincter of the stomach and as a result there is food regurgitation in the oesophagus and burning sensation in the epigastrium.

      Heart and cardiovascular system

      The uterus and the placenta need five times more blood supply compared thepre-pregnancy needs.As a result, the heart works more. You might notice a small drop in your blood pressure. You should not worry as this will return to normal levels during the 3rd trimester. However, if you blood pressure drops you might feel faint.

    • 3rd Trimester

      Uterus and cervix

      The weight of the uterus makes it more difficult for you to mobilize. At this stage the uterus is about 30 cm long, weights around 1 kg and has a capacity of 4-5 lt. As the fetus grows, the uterus puts pressure to the lungs and makes breathing difficult. It also puts pressure to the bladder and therefore you might experience urinary frequency.

      During the 3rd trimester you can often feel uterine Braxton Hicks contractions. This is a way of “preparation” for labour and is entirely normal. The cervix becomes softer before it starts dilating in order to facilitate the birth of the fetus.

      Heart and respiratory system

      Near term the woman needs to avoid the supine position because it could cause hypotension. This happens because the weight of the pregnant uterus puts increased pressure to the central veins and affects the return of blood to the heart.

      There is a tenfold increase in the amount of blood that the heart sends to the uterus compared to before pregnancy. Just before labour the respiratory rate doubles. You might observe a tendency for increased sweating due to the increased blood flow.


      Backache is more intense due to the weight of the fetus and to the relaxation of the pelvic ligaments.

      Normal weight gain in pregnancy

      The weight gain during pregnancy should be controlled. Ideally, you should take up to 10-12 kg in order for your pregnancy and labour to be easier. Excessive weight gain will adversary affect both you and your fetus.

      The weight that you are allowed to gain per month is 1 to 1.5 kg from the second trimester onwards. After the delivery you lose around 7.5 kg. As the uterus involutes you lose 2.5 kg more. In order to lose weight you should follow a balanced diet and reduce yourdaily caloric intake.

    Gennima | Gynaecology & Reproduction Center

    346 Kifisias Avenue, 15233 Chalandri - Athens, Hellas
    +30 210 68 16 100
    +30 210 68 30 321 (fax)