Dr Michelle O'Driscoll: Supporting baby through the fourth trimester

The fourth trimester is the first three months of your new baby's life. Here Dr Michelle O'Driscoll tells us how we can support your child through this time of development and change
Dr Michelle O'Driscoll: Supporting baby through the fourth trimester

Those first 12 weeks is a time of extensive development of baby’s little brain and nervous system, says Dr O'Driscoll. Picture: Stock

THE fourth trimester, as named by Dr Harvey Karp, is the first three months of your new-born’s life.

It’s a time of great physical and emotional adjustment for baby, who has had to leave the cosy, comforting confines of your womb, is adjusting to new and overwhelming stimuli, and has lots more development to do.

Those first 12 weeks is a time of extensive development of baby’s little brain and nervous system, much of which is not complete at the time of birth.

Babies are born not being able to see clearly, with multiple reflexes that they cannot control, and muscles that they still don’t have the strength to use. Synapses must join, neurons must form and new skills must be learned.

After the fourth trimester your little one will emerge with five fully developed senses and a budding personality.

And as their mum, your primary role is to support them through this time of development and change. Below are some things to bear in mind to aid you in this journey.

The 5 S’s

In those initial months, which can become a blur of nappies and night-feeds, it helps when your baby seems fussy and unsettled to try and recreate the environment that they’re used to; the womb! Some of the most successful soothing techniques based on this approach are summarised by the 5 S’s:

Swaddling – wrapping baby in a blanket in a way that restricts movement of arms and legs can instantly calm fussiness as it prevents baby’s startle reflex from interrupting sleep, but should be stopped once they start to roll over. Swaddle bags are available to buy, or you can try to master the perfect swaddle technique, while bearing in mind the safe sleep guidelines.

Side/stomach – although baby should always be put to sleep on their back, holding them on their side or stomach can put gentle pressure on their tummy and ease digestive discomfort.

Shush – the womb is a surprisingly noisy place due to blood flow and external noise. Mimic this environment with a white noise machine, by downloading an app on your phone that serves the same purpose, or by good old-fashined “shushing” yourself!

Suck – the sucking reflex is very soothing. Baby practiced sucking their thumb in the womb. Allow your new-born to self soothe via sucking, either on the breast or with a pacifier.

Swing – the womb was also a place of constant movement, which soothed your baby when you walked. Recreate this by rocking baby in your arms, or with one of the many baby products that rock baby for you, buying you some precious time hands-free!

Navigating the leaps

Just when you think you’ve nailed it and baby seems to be finding a rhythm or routine, expect a curve ball and for baby to almost regress in terms of fussiness. Usually this can be attributed either to a physical growth spurt or to a mental developmental “leap”, a stage where baby is mastering even more new skills than normal, and processing the world around them.

Download the Wonder Weeks app to familiarise yourself with the expected developmental “leaps” that baby will traverse. These occur periodically and continue until 18 months of age, but the initial leaps happen during that fourth trimester period, and can make everything feel very overwhelming indeed. The app is helpful to at least explain why things seem to have deteriorated, and to reassure you that yes, this fussiness and clinginess is normal!


All this learning that baby is doing can be supported and encouraged by interaction with you and other family members.

Cooing, smiling, talking and engaging with them helps to establish those all- important neural connections and facilitates them in reaching their developmental milestones.

Before you know it, your new-born bundle will be smiling and cooing back at you, and that’s when the most rewarding part of parenthood begins.

If in doubt…

At the six week check-up, mum and baby get signed off by the GP despite being very much still in the throes of adjustment, and support from there on can feel limited.

Use baby’s GP visit card, or the very accessible services of your pharmacist to ask as many questions as you need about baby’s health. There is no such thing as a stupid question, and you can be sure that plenty more mums have asked before you.

It can be difficult to discern between normal new-born fussiness and something untoward health-wise. Things like reflux sometimes warrant treatment if baby is very uncomfortable or distressed.

Don’t ever leave it to chance and always trust your gut; mamma knows best, and if in doubt get baby checked out.

As their mum, your primary role is to support them through this time of development and change.

Dr Michelle O’Driscoll is a pharmacist, researcher and founder of InTuition, a health and wellness education company. Her research lies in the area of mental health education, and through her company InTuition she delivers health promotion workshops to corporate and academic organisations nationally

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