What is the Fourth Trimester?

(10 minute read)

This blog post has been brought to you by Louisa Hirst - Postnatal Doula, Infant Feeding Coach and Author of the Parent Prep Book.

Whenever I am teaching an antenatal class to expectant couples I always begin by discussing what happens when a rabbit is born (bear with me here). Rabits are cache mammals. Once born they are left in the nest to fend for themselves for up to twelve hours at a time, so their milk is high in fat and protein to allow them to withstand this. Nest mammals, such as cats and dogs, can be left for chunks of time too (roughly every four hours), so again their milk is a little higher in fat and protein. Then we have animals such as horses and pigs, or follow mammals, who have well developed gross motor skills at birth which allow them to keep up with Mum. They also eat solids after just a few weeks of being born.

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Why am I telling expectant parents all of this you might wonder? Well let’s compare these mammals to humans, or carry mammals. We are the most immature of all mammals at birth. We don’t have well developed gross motor skills, we don’t eat solids within a few weeks and the fat and protein content of our milk is far lower. We require constant, round the clock care and need to be in close contact with our caregiver to have our needs met. It’s also interesting to note that human babies’ brains are only 30% developed of that of an adults’, compared to other mammals whose brains are 50% developed of the adult size. 

But why can’t we just stay in the snuggly womb for longer so that we come out more mature and independent I hear you ask? Well, this isn’t physically possible because we walk upright on two legs (instead of stooping forwards and walking on two arms and two legs, or four legs), meaning we have a smaller pelvis. Therefore, we can’t gestate a baby long enough for their brain to be fully developed.

So, when you hear people talk about the fourth trimester, they are describing the first three months your baby is earthside but should still be gestating. But I have a bit of an issue with this because by labelling the period of time it can lead many to feel that it takes this long for babies to adjust and that after this period a baby should be becoming more independent, sleeping through and feeding less frequently. However, anyone who has had a baby or who has worked alongside newborns will tell you that this isn’t normally the case (sorry!). Babies don’t get to three months and then all of a sudden stop needing food and cuddles.

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Let’s put ourselves in our baby’s shoes… They’ve come from a warm, cosy environment where they’ve been held naked and secure in water, had nutrition on tap and the constant muffled sound of Mum’s heartbeat and gurgling digestive system. The womb is a dark red and the only smell is that of the amniotic fluid. Then, all of sudden they’re thrust into our world… ‘What on earth is that smell?’ ‘That’s Great Aunt June’s Coco Chanel…’ ‘Woah, what’s this itchy material on my skin?’ ‘Oh, they’re called clothes and you’re going to start experiencing what it feels like to be hot and cold now…’ ‘Help! I don’t know where I am. You’ve put me flat on my back in a box.’ ‘That’s your cot, it’s where the book says you need to sleep or I’ll be making a rod for my own back.’ You get the idea…

So, what can we do to ease this transition for babies from womb to world?

Keeping your baby skin to skin is always an excellent place to start. Your nipples secrete a substance which smells like amniotic fluid, so being near your breasts will feel very comforting to him, even if you don’t plan to breastfeed. As he lays on your chest he will also hear the sound of your heartbeat and your voice which he has come to know so well over the last nine months, and your temperature and breathing will regulate his. It is totally normal for a baby to dislike being put down, after all you’re all he knows. Whilst this can feel overwhelming for you and particularly tough when you’re exhausted, he is in no way manipulating you, and this is why allowing others to take care of you is so vital. 

To mimic the blood rushing through the umbilical cord and the noises of the womb world you might like to consider playing some white noise- this is the noise the radio makes between stations when there’s no signal. You can find this on CDs or digital music apps. If you choose to play this during sleep then ensure it plays throughout the duration of the night/nap for consistency and isn’t too loud.

Babies often find motion very comforting- after all they’ve been swaying gently in your tummy all this time. Offering baby a gentle rock or a bottom pat often soothes them, or a ride out in the car (take them out of their car seat regularly) or pram. Once you’ve had your postnatal checks completed you might like to bounce with your baby on your birthing ball too!

Slings really help to soothe a baby- he can hear your heartbeat and smell you which can be very reassuring. Carrying also helps regulate baby’s temperature whilst he’s next to you and can help baby bring up wind. Carrying nurtures the parent baby dyad and increases responsive feeding and parenting. By being closer to your baby you are more likely to pick up on his hunger and tiredness cues. Having your baby close keeps levels of Oxytocin (the love hormone) high, which will aid breastfeeding and encourage bonding. The motion babies experience whilst in the sling helps their vestibular apparatus develop, aiding balance, and when correctly worn they support the development of a healthy spine and hips. Language development is also promoted as you talk to baby whilst you carry him. Another benefit is that the caregiver is hands free which is really helpful when you need to run an errand or look after siblings.

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My final tip is to ditch the routine in the book and follow your baby! Very sadly, there are still books/apps/social media accounts out there that scare parents into thinking that if they don’t get their baby into a routine and self-settling in their cots then they’re never going to get a solid night sleep again. Firstly, anyone who thinks that a baby can self-settle needs to go back and do some studying! Also, many routines out there first became popular around the 1900s and were based on observations of grazing mammals- scroll back up and you’ll be reminded of how drastically different these are to us humans and how a routine for them is very unlikely to suit us!

Doula Lou




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