baby's development in the third trimester

Baby’s development in the third trimester (weeks 28 – birth)

Pregnancy usually lasts 40 weeks, counting from the first day of your last period, and is grouped into three trimesters. Find out everything about your baby’s development in the third trimester.

Week 28

By this time, your baby weighs around 1kg and is now perfectly formed. The heartbeat can be heard through a stethoscope and your partner might even be able to hear it by putting an ear to your belly.

Your baby will continue to put on weight, gaining more and more fat that appears under the skin. Your baby is now ‘filling out’.

baby's development in the third trimester

Week 29 – 32

You’ll notice that your baby is very active at this stage. You should be aware of your baby’s own pattern of movements. If this pattern changes, contact your midwife or hospital to tell them.

By now, your baby can suck its thumb or fingers, as the sucking reflex is developing. The white, greasy vernix and the soft, furry lanugo that have covered your baby’s skin for some time, will now begin to disappear. Your baby’s eyes can focus now, and the lungs are developing rapidly.

baby's development in the third trimester

Around week 32, the baby will turn and lie with their head pointing downwards, ready for birth. This is known as ‘cephalic presentation’. Don’t worry if your baby isn’t lying head down at this stage, there’s still time for them to turn.

Week 33 – 36

By week 33, the baby’s brain and nervous system are fully developed. The bones continue to harden, apart from the skull bones, for they need to stay soft and separated until after birth, to make the journey through the birth canal easier.

Since there’s less room to move about at this point, your baby will be curled up in the uterus, with legs bent up towards the chest. Your baby will still change position, and you’ll be able to feel and see the movements on the surface of your bump.

baby's development in the third trimester

By week 36, your baby’s lungs are fully formed and will be able to take their first breath after the birth. The digestive system is fully formed as well, and will be able to deal with breast milk.

If your baby is a boy, his testicles will begin to descend from his abdomen into his scrotum.

Week 37 – 40

At week 37, your pregnancy is considered full-term. The average baby weighs around 3-4kg by now. Your baby’s digestive system will contain meconium – a sticky green substance that will form your baby’s first poo after birth. It may include bits of the lanugo that covered your baby earlier in pregnancy. At this point, the lanugo  that covered your baby is now almost gone, however some babies may have small patches of it on their body when they’re born.

In the last weeks, some time before birth, the baby’s head should move down into your pelvis. You may notice, that your bump seems to move down a little. However, sometimes the head doesn’t engage until labour starts.

baby's development in the third trimester

Your baby is ready to be born, and you’ll be meeting her or him some time in the next few weeks.

Over 40

Pregnancy normally lasts about 40 weeks, therefore after week 40, your baby is considered overdue. At week 40 and 41, your midwife will offer you a membrane sweep, which involves having a vaginal examination that stimulates the cervix to produce hormones that may trigger natural labour. If you’re not comfortable with this, you can discuss it with your midwife. If your labour still doesn’t start naturally after this, your midwife or doctor will suggest a date to have your labour induced.

If you don’t want your labour to be induced and your pregnancy continues to 42 weeks or beyond, you and your baby will be monitored. If there are any concerns about your baby, your doctor will suggest that labour is induced. It’s your choice whether to have your labour induced or not.

Credit: NHS

Ask Allison

Q My sister-in-law and I both work three-day weeks and we help each
other out with child minding on our working days, which up until recently has worked out really well. Between us, our kids are aged between five and nine years – the problem is that it’s now become quite apparent that we have very different parenting styles. I prefer my two daughters (seven and nine) to have a structured day. For example, in my house, we have allocated times for television and iPads, etc. My sister-in-law, however, lets the kids run loose after school – homework is ignored and my kids end up wired after eating sugary treats all afternoon. I am considering looking at after-school childcare for the kids, but I’m worried that this is going to cause a family argument. Is there a diplomatic way that I can ask my sister-in-law to introduce some discipline into her child-minding days? It certainly doesn’t do her two kids any harm when I am minding them in my own house!

In a word, no, there is no diplomatic way to do this as it may very likely seem like your saying that your parenting style is better than
hers. As L’Óreal says, ‘now here comes the science bit.’ Dr. Kaylene
Henderson, a child psychiatrist, wrote a very interesting blog about ‘the
science behind the Mummy Wars’. She explains that before she had
children of her own she hadn’t been aware of how parents have a
very specific sense of the right parenting style. She also found that parents could be very definite in defending their chosen parenting style. Dr. Henderson, who describes herself as a curious, scientific, open-minded person, was surprised at how defensive parents could be and, at times, of their judgemental attitude towards each other. She explained the neurology of the Mummy Wars; okay, I’ll need you to bear with me for a second. Warning; I’m about to use some neuro-techie language.

Why do we judge each other?
As we have all had different experiences, this means that we all have very different memories stored in our brains. Most of our memories are ‘explicit’ memories – these are ones that we can recall easily such as important dates that mean something to us; important birthdays, special events or stories of and about our lives.
There is another type of memory called ‘implicit’ memory that plays a
key role in our parenting. This type of memory is the stuff that you do on autopilot. Psychologists call these heuristics or rules of thumb –
such as tying your shoelace, or driving your car (once you have learnt
to do both first!). Otherwise we’d really waste a huge amount of time
pondering over tasks that we have readily available to us. This seems to be where the science bit of our parenting style kicks in. This implicit memory goes all the way back to when you were an infant being parented by your parents. This is when you started the process of storing up how they did it into your memories.
Unless you make a conscious choice and effort to parent differently, what you saw and unconsciously learnt will be your automatic go-to parenting style.

We learn habits
This can really kick into gear when we feel our parenting style is
being mirrored or highlighted by disapproval from another parent. I know the cold sweat you feel when your child decides to make their outstanding bad behaviour performance at, of course, the most public and worst time. The implicit autopilot of how your parents dealt with these outbursts will flow unconsciously from you if you haven’t worked super hard to be aware and consciously change the old habits.
What’s happening for the on-looking parent is that they see you doing something they are used to doing, but you are doing it all wrong. Simply, because that is not how they know how to do it.

Find a way that works
You both have different parenting styles – who is to say which type is correct? You just need to know what works best for your family and that’s the bottom line. The irksome feelings won’t go away. You can talk to your sister-in-law, but I’m adding a caveat that it would be hard not to hurt her feelings. What we’re possibly looking at is that you prefer a more structured form of parenting, whereas your sister-in-law has a more permissive style. I’m not sure the two styles can mix, the mixture is a bit like oil and water.
If a collaborative shared form of parenting style can be agreed upon, then that is great, but our learnt hardwiring may prove difficult to change despite the intent to do so.
Perhaps, your own instinct of changing childcare might work best for you. In terms of making childcare work; the fit is ultimately the most
important aspect as you want a cohesive congruent feeling of the other caregiver to just ‘getting it’, like in any good partnership. Best of luck
with this and I wish you both well.


Ask Sarah

Q I’ve heard a lot about the Paleo diet and as I am very interested in reducing the amount of processed foods and grain based meals my family eats, we are considering following this diet. From what I read it seems to be a back-to-basics type of eating. Is a Paleo diet safe for children? My kids are aged seven and nine.

A The Paleo diet is one of the most fashionable diets around at the moment. It is also known as the ‘caveman diet’ and is based on cutting out processed foods, starchy foods like bread and potatoes and eating more meat, vegetables and fruit.
As fad diets go, it is not the worst but there are some good and bad sides to it. Reducing the amount of processed foods we eat is always a good idea and by doing that you will usually reduce the amount of fat, salt and sugar you eat, which is a good thing! The problem with the Paleo diet is that it also cuts out dairy (on the basis that cavemen didn’t drink milk) and this means that the diet is very low in calcium. For this reason it is really not suitable for children who do need a lot of calcium for growing bones. How did cavemen manage without dairy? They ate a lot more food than we do (up to 10,000 calories per day compared to the 2,000 most of us eat). By eating that amount of food they were able to pick up just enough calcium from green vegetables and seeds. To put it in perspective, you would need to eat 16 servings of broccoli a day to get all the calcium you need. This is easier to do if you eat 10,000 calories per day rather than 2,000.
The other problem with the paleo diet is that it is not entirely based in science. Many of the Paleo diets out there say you should not eat wheat, even though we know that cavemen did in fact eat wheat and other grains. These diets also don’t recommend that you eat blubber and the big lumps of fat that were also a large part of the caveman diet!
A final problem is that many Paleo diets encourage people to cut out beans and lentils and to get their protein from meat and fish instead. Many studies over the last few years are clear that eating too much animal protein is linked with more cancer and heart disease. Eating some vegetarian meals based on beans and lentils is a great way to get your protein without always going for meat.
Is this a diet we should follow? I think there is a lot we can learn from the Paleo diets. We could all do with eating less salt, sugar and processed foods and adding in more nuts and seeds as well as more vegetables. However, I think following a strict Paleo diet could lead to low levels of calcium and vitamin D and so it is not suitable for children or teens and adults would need to think about a calcium supplement.