Tell Me About My Baby
Week 01 to Week 04
This week you would have had your last menstrual period before you conceive. That means your expected delivery date is calculated as 40 weeks from the first day of your last menstrual period and this week is considered as part of your pregnancy period. Your oestrogen hormone levels increase and a special kind of mucous like substance lines your uterus and the fallopian tubes to facilitate transit of sperms into the tubes. This mucous also protects and keeps the sperms alive for about 3-5 days. While you plan to conceive, prepare yourself well. Avoid alcohol, drugs, tobacco or any other substances that are harmful to your baby. Eat a healthy diet rich in vitamins, particularly folic acid.
You would have released an ovum (egg) around this time and if viable sperm remains in the fallopian tube, fertilisation of the egg by the sperm may take place close to the end of this week. You would have conceived and a new life starts growing within you!
During these seven days after conception, the fertilised egg undergoes a series of cell division beginning from breakdown into two cells, then four, followed by eight cells and then goes on dividing as it travels from the fallopian tube into your uterus (womb). Once in the womb, this group of cells appears like a small ball (morula). This ball of cells becomes fluid-filled (blastocyst) and towards the end of this week, blastocyst gets embedded into the lining of your womb. This is called implantation process and takes about six days to be completed. Once implanted, the developing embryo can access your blood supply and receive nutrition. Your baby starts producing a hormone called human chorionic gonadotrophin (HCG), which prevents your menstrual periods and turns your pregnancy test positive.
Your baby, which is a ball of cells just about the size of an apple seed, is now called an embryo. It is made of 2 cell layers called epiblast and hypoblast, which form the future organs and tissues of the baby. Amnion and the yolk sac are two other structures that develop this week. The amnion, with its amniotic fluid, envelops and protects the growing embryo. The yolk sac makes the blood that nourishes the embryo until the placenta forms and takes over the function.
Week 05 to Week 07
Your baby, which looked like a mass of cells until now, gains a distinct shape this week. The embryo is about half a cm long and appears as a tadpole. The neural tube develops, which will later become your baby’s spinal cord and brain. Your baby’s heart and other vital organs, such as kidneys and liver, start developing. The placenta also forms at this time and your baby gets nourishment from your blood through the placenta.
Your baby has grown to about the size of a lentil by now. The brain and spinal cord are developing at a faster rate. Your baby has its facial features developing with those dark spots that transform into eyes and the pits on either side of the head make up the ears. The baby’s heart starts beating around this week and the heart rate can even be detected on an ultrasound during your prenatal visit. Small buds protrude out that eventually form your baby’s hands and feet. The digestive and respiratory system organs start forming this week.
From now onwards your baby, almost the size of a grape, enters a very active developmental stage and at the same time starts adapting to life inside your womb. The umbilical cord, which acts as a linkage between you and your baby throughout pregnancy, has formed by now. This serves as a portal to provide oxygen and nutrition to your baby and also for waste disposal from the baby’s body.
Your baby is growing at a rapid pace and all the body parts that have started forming in the earlier weeks (heart and brain) differentiate and become complex. Your baby’s digestive tract and lungs also continue to develop. At the end of the arm bud, which formed last week, a small hand, which looks like a paddle, appears. By this week the baby’s face acquires a distinct shape, as facial features such as the mouth, nostrils, ears and eyes, become more defined.
Week 08 to Week 12
Your baby measures almost 1.5 cm by this week. A lot of change takes place this week. The cute little fingers and toes, which you long to cuddle with, begin to form. Your baby can now bend its hand at the elbow and wrist. The eyes become more evident as they form pigment and also eyelids form to protect the eyes. The buds that develop into your baby’s genital organs also appear this week.
Your baby now appears like a peapod and weighs around 2-3grams. By the end of this week, your baby will measure up to 2.3 cm in length. The tail like extension at the end of the spinal cord disappears and the baby’s head grows very large compared to the rest of the body. The hands have grown longer and the fingers become clearly distinguishable. The baby’s genitals start to develop from the buds that appeared in the previous week. Also the internal reproductive organs, such as testes and ovaries, begin forming this week. Your baby may make its first movements in this week, which can be well appreciated on an ultrasound.
By the end of this week your baby has crossed the embryonic period and will be regarded as a fetus from the next week onwards. The fetus measures 3 cm and weighs not more than 4 grams. Your baby starts developing very fine details, such as fingernails and hair, as it grows each day. The vital organs – the heart, liver, kidneys, brain and lungs have formed completely and started their function. Tooth buds appear inside the mouth. If the fetus is male, then its testes begin producing testosterone, the male hormone.
You are heading towards the end of the first trimester. Your baby starts active movements like kicking and stretching. Your baby’s fingers and toes have separated and the baby grows rapidly from now on until 20 weeks. The face continues to develop and the ears take their final location, on the sides of the head. Your baby’s head seems larger and is at least half the baby’s length.
This week marks the end of your first trimester. The baby’s vocal cords form this week. Your baby’s kidneys start to function, as the amniotic fluid your baby swallows is passed out in the form of urine. The eyes, which were on the side of the head, come closer together. Brain development continues and by the end of this week your baby may be about 5.5 cm long and weigh around 14 grams.
Week 13 to Week 15
You have stepped into the second trimester of your pregnancy. You have your fully developed placenta to provide your baby enough oxygen, nutrients and also dispose waste. Along with this, the placenta starts producing hormones, progesterone and oestrogen that maintain your pregnancy. Your baby’s eyelids get fused together, in order to protect the developing eyes. Surprisingly, your baby’s unique fingerprints have also developed by this time. Your baby measures around 7 to 8 cm long and weighs about 23 grams.
During this week very fine colourless hair develops and covers most of the baby’s body. It is called lanugo and it usually disappears just before birth. Eyebrows also start growing, as does the hair on the scalp. Your baby’s genitals have also completed development. Your baby can make expressions – squint, frown or grimace and is able to grasp and suck its thumb. By now your baby’s body starts growing faster than the head portion and measures about 9 cm in length and weighs around 43 grams.
Your baby is now about 15 cm in length head-to-toe and may weigh around 120 grams by the end of this week. The head portion may account for almost one third of the baby’s body length. If you have been pregnant before, you may start feeling sensations of your baby’s movements in this week. Your baby is able to make some facial expressions and has the ability of grasping with hands and sucking the thumb. Your baby may start exploring inside your womb with its little hands! The baby’s vocal chords have also formed by now. The amount of amniotic fluid surrounding your baby also increases, allowing it to move around freely in the womb. Hair continues growing on the head and eyebrows. The skeletal system and muscles continue developing, due to which the baby is able to move its arms and legs.
Week 16 to Week 18
Your baby has grown up to the size of a pear fruit and in the following weeks there will be rapid growth in your baby. Your baby is able to hold its head in an erect position and can make facial expressions such as squinting and frowning. Besides these activities your baby may also catch hold of the umbilical cord and start playing with it! The circulatory system and urinary system are fully functional and your baby inhales and exhales the amniotic fluid through the lungs.
Your baby may measure up to 19 cm head-to-toe and weigh almost 280 grams by the end of this week. The baby’s skin appears transparent and wrinkled, as the fat layer underneath has not developed yet. The blood vessels beneath the skin can be seen and makes the skin appear a purple-red colour. A fine layer of hair, called lanugo, covers your baby’s body and protects the tender baby skin until it is shed a few weeks before birth. Your baby begins exploring its own body with their hands and there is an ample amount of amniotic fluid for the baby to swim around and shift position very often.
An ultrasound scan is usually done between 18 and 20 weeks, during which you may see your baby kick, move arms or even suck the thumb. Your baby’s chest moves up and down when it inhales and exhales amniotic fluid, in a similar way as while breathing. The ears take their final position and in the following weeks your baby may listen to your voice! The middle ear bones and nerves from the brain have developed and your baby can make out sounds of blood gushing through the umbilical cord and your heartbeat. Your baby’s bones, which have been soft until now, start to harden or ossify during this week.
Week 19 to Week 22
By the end of this week your baby may measure about 22 cm head-to-toe and weigh around 340 grams. Your baby’s fingernails have completely formed and fingerprints can be seen engraved in their thin skin. Permanent tooth buds appear behind the primary tooth buds deep within the gums. A waxy layer, called vernix caseosa, covers and protects your baby’s subtle skin from harm.
You have completed almost half of your journey through pregnancy this week! Your baby grows rapidly taking up more space in the womb. As your baby continues growing you can feel more pressure on your lungs, stomach and bladder. Your baby’s skin develops into layers and becomes thicker below the vernix caseosa. Hairs and nails keep growing.
Your baby will be measuring around 25 cm from head-to-toe and weighing slightly less than half a kg by this week. The baby’s eyelids remain fused but the retina of the eye has formed completely. Eyelashes and eyebrows have formed. The hair follicles develop pigments that give your baby’s hair its colour. At this stage your baby lies in a crossed position with their feet towards one side of your stomach and their head on the other side. Bone marrow has now developed well enough to take over the production of blood cells from the baby’s liver and spleen.
Your baby looks more proportional and weighs around 430 grams and nearly 27 cm from head-to-toe. The first tooth buds have appeared in the baby’s gums. By the end of 22 weeks the baby’s nervous system develops completely and the connection between the brain and spinal cord matures. Your baby is now able to recognise light, sound and the feeling of touch, warmth and pain. The taste buds have begun forming on the tongue. The baby’s reproductive system also continues developing. The testes start descending from the abdomen, if it is a baby boy, and in girls the uterus, ovaries and vagina would have developed.
Week 23 to Week 25
You may observe that your baby tends to be more active this week, particularly during the time when you are resting. The baby adopts a distinct pattern of sleep though they sleep for most of the time. By now your baby may measure up to 28 cm and weigh approximately 600 grams. A fat layer starts forming in-between the muscles and skin and covers the blood vessels, giving a better skin complexion.
At 24 weeks babies will have increased breathing patterns. A substance called surfactant is produced in the baby’s lungs and lines the lungs to help the baby breathe after it is born. Your baby may weigh more than 600 grams by now and measure up to 30 cm in length. The baby’s skin is very thin and delicate and has a little amount of body fat.
Your baby can now hear and recognise your voice and be calmed by listening to various types of music. The eyelids can open; your baby can even blink and react to bright light. Your baby is about 33 cm in length and may weigh about 800 grams. The baby’s movements become more regular and you may observe the baby has resting and active periods.
Your baby’ skin may be wrinkled though the body weight is about 907 grams. The baby will steadily gain weight in the following 14 weeks. As the nerves in the ears have developed completely, response to sound becomes more consistent. The baby’s brain also develops intensely as the baby grows at a rapid rate. Your baby continues to take small breaths of fluid surrounding it.
In the 27th week of pregnancy your baby weighs about 1100 grams and measures 37 cm. The immune system develops in your baby as your natural antibodies pass into the baby through the placenta. Your baby is now able to coordinate the ‘suck and swallow’ action which is essential for feeding after birth. The ability to distinguish light from dark also develops by now. Your baby will almost appear the way they are going to look at birth, except that they will be thinner and smaller.
By the end of week 28 your baby may measure about 38 cm from head-to-toe and weigh slightly over 1000 grams. In this week your baby can open their eyes and turn their head towards a continuous bright source of light from outside. The layers of fat continue to deposit and hair growth also continues. The baby’s brain folds and grooves also develop and expand.
The third trimester begins from the 29th week and lasts until birth, which is around 40 weeks. Your baby weighs about 1350 grams and may be around 40 cm in length. The baby’s brain increases in size and becomes more complex. The pupils in the baby’s eyes can react to light and your baby can focus without much difficulty and view dim shapes. Your baby’s movements continue to be more active and in case you notice a decrease in movements, consult your doctor.
Your baby will continue gaining weight rather than growing in length from now onwards. Your baby may weigh around 1400 grams and continue depositing fat layers to gain weight. A special kind of fat called brown adipose tissue gets deposited, which helps to regulate newborn infant’s body temperature and serves as an important source of heat production after birth. About 1 litre of amniotic fluid may surround your baby now, but its level decreases as baby grows. Your baby’s lungs are fully developed and the baby may repeatedly move the diaphragm imitating breathing movements. Your baby may also get hiccups, which are felt as a rhythmic jerky motion within your womb.
Your baby now weighs around 1700 grams and looks slightly chubby. The head-to-toe length of the baby would be about 43 cm. Your baby’s lungs produce more and more amounts of surfactant, a fatty liquid that keeps the lining of the lungs moist and efficient enough for breathing. The ‘suck and swallow’ action necessary for the baby to feed after birth gets fully coordinated by the end of this week. Your baby may swallow some amount of amniotic fluid and also pass several cups of ‘urine’ through the bladder back into the amniotic fluid around it. You may feel your baby does not make as many movements as before, but this is because of lack of space in the womb as the baby grows bigger.
Your baby will have hair on their head, eyelashes and eyebrows evident by now. The fine hair, which covered the baby’s body from the second trimester, disappears but some hairs may persist at birth on the back and shoulders. Your baby keeps practicing breathing movements by inhaling amniotic fluid and exercising the lungs! If you are carrying a baby boy, his testicles descend from the abdomen into the scrotum.
Your baby will turn around and be in a ‘head down’ position until birth. The baby’s movements may change into stretches and twists as it grows bigger and there is relatively less space to move around in the womb. Your baby will weigh about 2100 grams and measure approximately 45 cm in length. During the remaining 6 weeks, the main task for your baby is to grow bigger by gaining weight and to boost the immune system with your antibodies. Now, your baby’s brain has billions of well developed nerve cells which help your baby coordinate with the in-utero environment by senses of hearing, sight and touch. Your baby will be able to distinguish different flavours, whether sweet or sour! Your baby is asleep most of the time and may even experience dreams!
Week 34 to Week 36
At 34 weeks fat layers continue to deposit and your baby weighs around 2200 grams by now. Your baby’s nervous system continues to mature and the lungs are almost fully developed. You can even talk to your baby, as the hearing ability is fully developed. The fine hair (lanugo) has fallen off but the waxy covering on your baby’s skin, vernix caseosa, becomes thicker.
Your baby’s expected delivery date is fast approaching and your baby is now in normal proportion and plump! Your baby could weigh around 2600 grams and measure up to 47 cm head-to-toe by this week. From now onwards the overall growth of your baby becomes slow but weight gain increases considerably up to approximately 230 grams per week. From this week the most rapid weight gain period begins and fat deposits throughout the baby’s body, particularly around the shoulders.
Your pregnancy completes full-term by the end of this week and you could give birth to your baby any time from now! Your baby may weigh about 2700 grams and you may feel increasing pressure in the lower part of your abdomen. Your baby’s cheeks become chubbier, which adds to the fullness of your baby’s face. While your baby’s head is in the pelvis, the skull bones may also move in relation to one another (molding). It facilitates easy passage of your baby through the birth canal.
Week 37 to Week 40
Your baby may weigh about 3000 grams and measure almost 48.5 cm head-to-toe in length. Your baby is regarded as ‘full-term’ or being “on-time” if born after this week. The thick white layer on baby’s skin (vernix) remains, but the fine hair covering the body, lanugo, would have disappeared by this week. However, fat continues depositing at the rate of 14 grams a day!
You are just two weeks away from holding your little one in your hands! Though the baby’s growth has slowed down, fat still accumulates. Waste substances begin collecting in the baby’s intestines. Dead skin cells, intestinal cells and lanugo hair pile-up to form the greenish-black meconium, the baby’s first bowel movement.
Nearly all of the vernix coated on the baby’s skin has disappeared but there may be some remaining in the armpits or groin areas. Your baby’s breathing exercises usually stop about 24-48 hours prior to commencement of the labour. About 75-100 ml of amniotic fluid remains in the baby’s lungs and hormones released during labour initiates absorption of fluid from the lungs into the blood stream. The umbilical cord may become entangled around the baby’s neck sometimes, in this case a Caesarean section would be required if it causes problems.
After much expectation and preparation, you may welcome your baby this week. Your baby, at full-term, may weigh in the range of 2800 grams to 4500 grams and measure somewhere around 46 to 56 cm in length. Your newborn may have slight variations, such as a misshapen head, vernix coating, skin discolourations, dry patches or rashes. All these are quite normal and will resolve in few days.