By Cristina Mestre Ferrer BSc, MSc (embryologist).
Last Update: 02/10/2015

In the eighth month of pregnancy, fetal growth is considerable. During this month, the foetus gains half the weight it will have at birth, 1,600 grams approximately. Therefore, the foetus occupies most of the uterine space and puts pressure of the mother’s bladder. At the same time, the mother’s belly volume increases, making it hard for her to move.

The different sections of this article have been assembled into the following table of contents.

General changes by week

  • Your child grows from about 39 cm in length at the beginning of the eighth month of pregnancy to about 42 cm at the end.
  • The baby’s weight changes from about 1.320 grams to 1.800 grams, on average.

The baby’s brain continues to develop. The olfactory neurons are formed and the baby begins to perceive strong odours. The hair that covered the baby’s body begins to fall away.

Fetal movements are intense and his kicks can make it harder for you to breath for a few seconds. Sometimes the baby’s movements are jerky, this typically happens because the baby swallows amniotic fluid and hiccups.

Week 29

At this stage, the baby starts putting pressure on your internal organs. At the end of this week, the baby already measures 39cm and weighs approximately 1.320 grams. The size of the baby’s head is already proportional to the rest of his body. You can find more information about the baby’s size in the following article: 29 weeks pregnant.

During this week, you will become aware of the speed at which the baby is growing. We could compare his size to that of a small melon. Regarding the head, which as we mentioned before is proportional to the body, it is still developing in order to allow the brain to grow. The lungs, muscles, and other organs are also still evolving.

Good nutrition is important because the foetus growth makes you need more nutrients and vitamins. We recommend the ingestion of lots of calcium, iron, folic acid, protein and vitamin C. Calcium is especially important for the proper development of baby’s skeleton.

Regarding the mother’s body, you may feel a little more oppressed than before. It is normal to feel this way because the foetus is growing very fast. It will move and you’ll be able to distinguish those movements more clearly. You may also feel constipated. All these symptoms are normal and happen due to increased volumes of progesterone in your body.

Week 30

This week is especially emotional. Olfactory neurons are formed and the unborn child begins to recognize odors. The baby is also able to distinguish between voices and can recognize his mother’s voice. You can find a summary of all the symptoms in the article: 30 weeks pregnant.

Your belly will keep on growing and you will feel that your hips and pelvis are not as strong. This is a normal process as the baby grows. You should start exercising pelvic muscles, which will help during labour.

The baby’s size can cause some bladder discomfort and the need to pee more often. The baby’s kicks can also hurt your diaphragm and ribs.

Hormonal changes in your body may cause you to experience mood changes at any moment. Ask those around you to be patient and understanding. Above all, do not feel bad about it. Mood changes are normal and happen to the vast majority of women in your state.

Regarding the baby, new layers of vermix are being created. These layers of fat will help the baby maintain his own temperature once he is born. This also causes an increase in the baby’s weight. The foetus begins to distinguish lights and is able to follow them with his eyes.

Week 31

The future baby accumulates fat under the skin in order to maintain his own body temperature. The fine hair that covers his body also starts to disappear. At this stage, the baby measures, on average, 41cm and weighs 1.650 grams. You can find more information about this topic in the article 31 weeks pregnant.

The baby’s lungs are almost completely developed and he needs more and more space to move. The baby keeps growing and his measures are very similar to the ones he will have at the moment of birth.

At this stage of the pregnancy, the baby eliminates half a litter of urine into the amniotic fluid. From this week on, you’ll begin to feel strong contractions. This is normal, even if a little annoying. Monitor these contractions and make sure they don’t exceed an average of 5 contractions per hour.

Your breasts will begin to produce colostrums, which is a sign milk is forming. Colostrums is a liquid that feeds the baby until you produce enough milk to feed him.

At this point, you will have difficulties sleeping because your belly is larger and the baby occupies all your uterus. Try to eat frequently but in small amounts. Your lungs will also be affected by the pregnancy so don’t find it strange if you have some difficulty breathing.

Week 32

In this week the mother’s belly is considerably swollen and the baby is almost completely developed. You can find more information about this week in the article 32 weeks pregnant.

At 32 weeks, the baby is fully formed. In fact, there are very few differences between the brain of the fetus at this stage of pregnancy and after birth. It is believed that the unborn baby can already think and store some memories. All your baby is lacking at this point is pulmonary independency and a good layer of insulating fat. If the baby is not already positioned upside down, he will be during this week.

On the other hand, the amount of blood coursing through your body has doubled so heaviness is already a real nuisance. Remember you are almost giving birth so it’s normal for you to feel a little bloated. From this point on, half of the weight you gain goes directly to the baby, who needs an abundance of food.

Fatigue is almost continuous during this last period of pregnancy. It is normal for you to feel tired during these last few weeks, but you don’t need to worry because these symptoms are completely normal. This happens not only because of your weight gain, but also because your uterus is enlarged and pressed against your sides, which can make it difficult for you to breath.

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Authors and contributors

 Cristina Mestre Ferrer
BSc, MSc
Bachelor's Degree in Biological Sciences, Genetics & Human Reproduction from the University of Valencia (UV). Master's Degree in Biotechnology of Human Assisted Reproduction from the UV and the Valencian Infertility Institute (IVI). Embryologist at IVI Barcelona. More information
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