The First Trimester
There’s nothing to see yet, no growth to talk about. Of course, it may be hard to know the exact moment of conception but your due date will be counted from the first day of your last period and you then have 40 weeks to ‘B Day ‘ Nothing really starts to happen until around week 4
Not much happening. From week 1 – 4 there isn’t really anything of note that can be documented. But, wait for it, from week 4, all the activity starts for your little one.
Whoopee! Something IS happening. At week 4 your baby is roughly the size of a poppy seed. Have you actually looked at a poppy seed? It is a tiny, teeny, magical thing as is, of course, your baby.
At this important stage, the cells are beginning to separate into three layers which will be the unfolding of the development of skin and internal organs. Isn’t this just the most fascinating thing, to image this spectacular development in YOUR tummy! The embryo will split into two parts of which one part becomes the placenta. The placenta is what provides nutrients and oxygen to your baby the entire time that he or she is in your tummy. From the other half, the embryo starts to grow, creating something called a neural tube. This is where your baby’s brain, spinal cord and backbone will develop.
This week begins the most magical process of the first trimester – your baby’s heart begins to tick. It is not yet perceivable to our ears but it is happening nonetheless. The embryo now has three layers:-
- The Outer Ectoderm – will form the nervous system, ears, eyes, inner ear and the many connective tissues
- The Endoderm – will grow into internal organs like the lungs, intestines and bladder
- Middle Mesoderm – will eventually evolve to become the heart and circulatory system. Over the weeks to come, the mesoderm gradually evolves into bones, muscles, kidneys and reproductive organs
By the end of week 5, your baby will have tripled in size. Though still, in real terms, tiny of course, your baby is beginning to vaguely look like a baby. You, or your doctor, still won’t be able to hear his tiny heart, but it is beating strongly at around 150 beats a minute and it might be visible as a tiny, rapidly blinking dot on an ultrasound. The brain hemispheres are starting to be formed and it is possible for the brainwaves to be recorded.
Your baby is starting to develop his unique facial features. Little dark coloured dots show where his eyes and nostrils will be and a teeny mouth and cute ears are also starting to form. His brain is developing rapidly and he will be moving around a little, although you won’t feel this movement at this early stage. Growth has been staggering over the last few weeks and your little one is now a delicious little blueberry sized marvel.
Your little one now has webbed hands and feet. No, it doesn’t mean that he is going to be born as the man from Atlantis! The webbing will soon disappear as the hands and feet become perfectly formed. In the last two weeks, baby has quadrupled in size and is now a small blackberry. His features are becoming more defined and his eyelids are starting to take shape. His skin is transparent and you won’t yet be able to tell is your baby is a boy or a girl. Be patient as that comes soon.
Some of your baby’s organs are starting to develop:-
- Reproductive organs
- Gall bladder
His fingers are getting longer. Your baby is now double the size of the first few weeks. His head is tucked into his chest and about half the size of his body at this stage.
By the end of week 10, your baby is no longer considered to be an embryo but is now referred to as a fetus. The webbing on his hands and feet (week 8) is now disappearing to reveal perfectly detailed little hands and feet. This moving from the embryonic stage symbolizes a turning point for development dangers that may have been concerning you. This is generally why many parents to be wait for the first three months to be passed before they tell family and friends.
Baby’s skin is starting to thicken up a little and teeny hair follicles are starting to form. Interestingly, your baby is starting to have waking and sleeping cycles. It is said that these last from to 5-10 minutes at a time. He is now about the size of a small fig
Baby is now around 3” long. Growth has been exponential in the last month and will continue to be so as he develops. His organs are now formed and he will be taking in nutrients from the umbilical cord which will also get rid of waste from your baby’s body to clear toxins away. What an incredible system of nature this is! He is developing reflex responses and will be kicking and opening and closing his hands. At this stage, it is unlikely you will feel this movement.
That is the end of the first trimester
Baby is fully formed now with everything that needs, although his lungs need to carry on developing. Let’s find out what excitement happens in the second trimester
The Second Trimester
For the best part of the first trimester, your baby’s head was as big as his body but now his body is starting to catch up, get longer. This week his arms will become proportionate to his body. His ears and eyes are now in the right place on his head
Baby is now just a little under 3.5” and is starting to develop a little hair on his head. His eyes are still closed
Baby is now developing his facial expressions. The sexual organs are almost formed so any day now you can choose to have an ultrasound to determine if your baby is a boy or a girl.
Baby is now about 4.5” You may start feeling his moving around at this stage. He is certainly now looking like an actual baby, rather than the teeny poppy seed we started out with
Your baby is now proportional as his body has caught up with his head. He is now starting to plump up a little with body fat and he is over 5”
Your baby can now hear you! Oh boy, this has to be the most exciting time doesn’t it? You can talk to him, sing to him and begin to build the relationship before he is born. He will know your voice if you spend a lot of time talking to him
Baby could be 6-8” at this stage. His legs are now longer than his arms, which is exactly as it should be. You may feel his movement now but, if a first time mom, this may be a few more weeks away yet.
Your baby is looking more and more like a tiny human being each day now. He may have developed faint eyebrows and hair on his head
Baby is now measuring around 9-10” and is aware of your life patterns – eating, sleeping etc. He will be kicking and moving his fists around as he shifts inside of you. You may start feeling this now.
Baby’s once transparent skin is now opaque and he will be just under 11” His sense of touch is developing and his lungs are continuing to develop in preparation for when he comes out into the outside world
Brain cells are developing exponentially now which will control all of your baby’s movements, sensory abilities and life functions. A substance called surfactant is being produced which is necessary to prepare his lungs to breathe air when he is born.
As the inner ear develops, your baby can now tell if he is upside down or the right way up. He will respond to your voice, so do spend time talking and singing to him. Play soothing music and spend quality time relaxing with him
Baby is now just over 13.5” and his eyes are open. He is still being nourished from the umbilical cord which is thankfully protected from your baby grabbing it and moving around in your tummy. It is covered in gelatinous goo called Wharton’s jelly which keeps the umbilical cord from twisting and knotting as your baby continues kick, push and move
Baby is now approximately 14” what a whopper! You will probably be feeling his kicks and punches by now. His strong heartbeat can now probably he heard on the ultrasound and if your partner puts his head on your tummy. From this point on it is all about growth for your baby, so eat well, drink plenty of water and avoid alcohol and smoking. Baby will now probably have periods of activity followed by periods of rest. Hopefully this will coincide with your lifestyle.
You may notice that baby has been hiccuping which are simply involuntary movements of his diaphragm. He will be getting plumper now, creating the fat deposits that he will need to keep him warm when he is born and to give him energy.
This week, baby will begin to open his eyes and he will have pigment in his irises. This color may change though as apparently a baby’s eyes color can change for up to six months after he is born.
That is the second trimester completed, let’s find out what happens in the third trimester.
The Third Trimester
Baby is now approximately 15” and he will be getting stronger. Those baby kicks and punches may start becoming somewhat more noticeable.
Also, the part of the brain associated with intelligence and personality is becoming more complex. You may start being able to tell what your baby likes. Does he like heavy rock music (oh dear!) or does he love the soothing tones of meditation music? Seriously, this can be a fun time for you and baby as you start to get an inkling of his personality before he is born. How about food? Does he get agitated when you have a curry, or does he love fiery hot foods? Have some fun and tune in to your baby’s likes and dislikes.
Baby is now filling out, gaining about half a pound in weight each week. He needs that weight gain to pad out and protect his body, so do eat and drink well. As he is getting bigger, he will find it harder to move around simply due to lack of space but he will still be moving so stay alert to his movement. Always consult your doctor if you are worried at any point.
Baby is gaining weight now; he probably won’t get much bigger height wise but needs to fill out. He will be around 16” high and weigh around 3.5lb. Because of his size, he won’t be able to move around so much and will be forced into the fetal position. He may be feeling a little annoyed at this and show his displeasure by the odd kick or two! Tell him it isn’t that long now, sing and talk to him and deed him well by ensuring your diet is nutritious.
Weighing in at around 4lb now, baby is sleeping about 70% of the time. As his lungs are pretty much developed, should there be an early birth, he would stand a very good chance of surviving
You may find that baby is becoming less active now. This is purely because he has very little room now. He measures around 17” and will be putting weight on all the time. You may notice that his movements react to your life and eating/drinking patterns. Stay alert to see what he likes and dislikes
Baby is preparing for ‘B Day’ His bones are fully developed and he can turn his head and move from side to side. He is just under 18” in height and weighs just under 5lb.
At this point, baby would normally, as 97% do, have turned around with his head down pointing towards the cervix, in preparation to enter the birth canal. If baby hasn’t turned around naturally and is still positioned ‘head up’ then this is called a breach position. Try not to worry about it, in many circumstances your health provider can help to turn him manually by applying pressure to your tummy. This succeeds in around 65% of situations.
Baby’s growth will slow down from this point as nutrients are directed to gaining body weight rather than height.
The umbilical cord is starting to transfer antibodies to your baby in preparation for his birth. He needs these antibodies for when he leaves the security of your womb, to start breathing in his external world. Antibodies help him to resist germs and disease.
Babies come to term between 38-42 weeks so if your baby decided that he really wants a lot more room and wants to come out, then he will be perfectly safe if he chooses that. Everything he needs is fully formed so he can breathe, suckle and digest his food.
If baby is still lounging in your tummy, he will probably be between 18-19” tall and weigh between 6-9lbs. He is fully ready so be prepared for his announcement that he wants out.
Come on baby! Time to appear! Fully formed and ready for life, 40 weeks is the standard time when most babies have made their real life appearance. But, do not worry if he has opted to stay in there for a little while longer. He is safe in there and gives you an extra few days to prepare the nursery.
Hmmm, he really likes his home but it is soon time for him to have to come out. Hey baby, you can’t stay in there forever you know. Don’t be concerned, some babies like a little longer before they join our world. That’s fine, just talk to your health provider and be guided by her.
Clearly, baby is far too comfortable in his cozy, warm womb! If he has gone this far, it is likely that, when he opts to appear, he will be heavier than 9lbs.
Sweet dreams little one
Things you might like to know when you are pregnant. For example, what are the most common worries in the first trimester? And, can you avoid stretchmarks, is there anything you can do?
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