3rd Trimester foetal development
Baby is still growing. He is awake and reacts to noise and caresses on the belly. He is preparing to be born. His lungs continue to develop to be ready to take their first breath of air at birth. Below are the last stages of its development.
Week 29: he works hard!
At the beginning of third quarter, its digestive system is functional. He continues to drink a lot of amniotic fluid and records a range of flavors through your diet! In addition, fragrances carried by the amniotic fluid give him a first olfactory experience which may influence his preferences after birth.
At this stage of its development, its bones are fully developed, but they are still soft. His muscles are gaining volume. His eyes are partially open, and eyelashes are formed. The skin becomes smoother.
As he works hard, his nutritional needs become crucial. He needs a good amount of protein, vitamins and minerals (especially calcium and iron) that it will draw from your diet.
Inside the uterus, the space available to the fetus is limited. His movements become smaller, which does not prevent him from continuing to grow and stretch. And it shows!
This week, it measures about 34 cm, and it reached its first kilo.
Week 30: he keeps his eyes open
At this stage, the fetus eyes are open most of the time. He is even able to see, but his vision is limited. It can see from 20 to 30 cm in front of him. It also collects the sounds and voices.
The bodies are almost entirely formed except the kidneys and lungs that require more time.
Brain structures are strengthened. The sheath surrounding nerve fibers (myelin) continues to grow, and this will continue intensively in the early years of life. You will note, among others, the development of skills such as walking, speech and toilet training.
Bone marrow has taken over the liver and spleen for the production of red blood cells.
Its growth slows a bit, but he continues to gain weight.
Twenty-eight weeks after fertilization, the fetus measures about 35cm and weighs about 1.2 kg. The diameter of the head is 7.8 cm. It starts to feel a little cramped in the womb.
Week 31: Warm, thanks to its fat reserves
Another step towards the autonomy of your future baby: the central nervous system is now able to control the temperature of the body, through the body fat reserves. Moreover, the appearance of the fetus has changed: it is more round!
Inside the lungs, blood vessels have been developed. The respiratory movements are more regular.
The testicles are now descended into the scrotum. Oocytes – that will become eggs – have completed their development. They “sleep” until puberty, the onset of menstruation.
Some have already assumed an upside down position. Often, they keep this position until delivery.
Hair and fingernails continue to grow: you may be surprised at the length at birth.
Week 32: wriggles a lot!
He feels agitated and makes great movements of the arms or legs
At the end of pregnancy, the fetal weight gain takes place at unbelievable speed; he takes half of his birth weight during the last seven weeks of pregnancy.
Her heart beats at 130 to 140 beats per minute.
It measures 37 cm and weighs 1.5 kg. The diameter of the head is 8.2 cm.
Week 33: less room to move
The fetus has much less room to move. It is curled up: legs bent, arms crossed and chin on his knees.
He always wriggles a bit even if it moves a lot less compared to previous weeks. This decrease in activity of the fetus is normal at this stage.
If this is not done, the fetus will switch upside down for childbirth. His head builds on the bones of your pelvis where it will come down gradually.
If born now, the baby would have an average prematurity (the most common). His chances of survival are very good.
His weight is now 1.7 kg. It measures 39 cm, and the diameter of its head is 8.5 cm.
Week 34: from red to pink
During the last weeks of pregnancy, the fetus swallows a lot of amniotic fluid and pours a good amount of urine (about two tablespoons each hour) in the amniotic sac. The placenta works at full capacity to drain and eliminate waste, and your kidneys too! Remember to drink enough water. A simple trick, drink to satisfy your thirst and make sure that your urine color is not too dark. If you are well hydrated, your skin turgor is good, and your urine is pale yellow.
In its bowels, meconium accumulates. It will be eliminated in the early days after birth. It is the first stool.
At this point, the majority of organs and systems are now fully functional. Some still enjoy the last weeks to complete their maturation. This is the case of the lungs, bones, skin, nails and hair.
Bones continue to grow and thicken. The bones of the skull, however, remain malleable for delivery. They are not welded together. The fontanelle (the spaces between the bones) will not close until several months after birth
The placenta provides a large amount of calcium to the baby. The baby’s calcium level is now higher than that of the mother.
The skin of the fetus takes a pinkish tinge (instead of red). Nails now cover all the fingertips. Those toes, however, take a little more time to grow.
This week, the fetus measures about 40.5 cm and weighs about 2 kilos.
Week 35: a mature brain
This week marks the beginning of your last month of pregnancy. Two important structures have reached maturity. The brain has completed its fetal development. But it will continue to change throughout life. He keeps a plasticity that enables it to learn new things at any age.
It’s the same immune system of your future baby. During pregnancy, he has integrated his antibodies to form immunity first. Also, continue to develop after birth.
The last weeks of pregnancy are beneficial to the fetus. His digestive system and lungs are nearly mature. Moreover, it continues to develop its fat reserves for its birth. Now his little limbs become all round. Baby takes its time to be beautiful!
With 42 cm and 2.1 kg, it is increasingly cramped. Around him, there is only a liter of amniotic fluid around. The diameter of the head is 8.8 cm.
Week 36: This involves breathing
He Inspires and expires. Your future baby trains! Hic! Hic! He still has hiccups. It’s normal. This breathing exercise develops his lungs. But right now, he breathes amniotic fluid. He swallows the same time, and it gives him the hiccups. Of all the organs of the body, the development of the lungs is the longest.
Otherwise, it continues to gain weight. He now weighs around 2.2 kilos and measures 43 cm. It has beautiful round cheeks!
For childbirth, it gradually loses what he used as protection in the womb: the lanugo (down) and vernix (slime).
Week 37: finally ready for his childhood
Your unborn baby is now considered “term.” It can happen at any time. All his organs are functioning. It has enough strength in himself to survive and begin his childhood.
But it is the fetus that will decide, somehow, the moment of his birth. When it is too cramped, it will secrete a hormone that causes contractions. Meanwhile, you surely feel that his head is even more deeply engaged in the pelvic area. And from time to time, through the stretched skin of your belly, we can even recognize a little elbow or heel spring.
At this stage, it weighs about 2.4 kilograms and measures 45 cm. The diameter of the head is about 9.2 cm.
Week 38: vigorous movements
Baby is beautiful! The layer of vernix (the viscous substance that protects the skin from the amniotic fluid) is now detached and floats in the amniotic fluid that takes a milky color.
The heart is full, but will be slightly modified after birth, because some holes between heart chambers are no longer necessary. His movements are vigorous, and the grasping reflex is well developed.
Nine months after fertilization baby weighs about 2.7 kilograms and measures 47 cm.
Week 39: He is patiently sleeping and waiting
Your baby sleeps a lot; he is waiting. He has no more room to move. Its body parts are folded and close to the body, his chin resting on his knees.
Its growth is now slow but continues to grow. It weighs about 3 kilos and measures 48 cm.
Week 40: it will soon be among you!
All organs are now constituted, except the lungs which will complete their development at birth: they will need a few hours to find the rhythm of breathing. Now your future baby has all the reflexes required to initiate development in the outside world. The lanugo falls entirely during the week.
Its weight should not change until birth. Boys tend to be a bit bigger than girls at birth but remember that these are only averages. Many variations are possible and normal.
Does It take a little more time than the scheduled date? This is a very common situation, especially during a first pregnancy (only 5% of births occur on the due date). The physician will choose whether it is necessary to induce labor. Certainly, it will be here soon!