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Fourth Trimester – What to expect 3 months after birth

Fourth Trimester – What to expect 3 months after birth

The “fourth trimester” – what to expect during the first three months after birth

by Myriam Panard, International Board-Certified Lactation Consultant (IBCLC) for Lansinoh France

When you’re pregnant, it’s difficult to imagine what your days and nights will be like once your baby is born, especially if you’re a new mum. What might spring to mind is an image of your little one peacefully sleeping in a cot in the middle of a beautifully decorated nursery.

The reality is likely to be very different, especially during the first three months – often called the 4th trimester. Your new baby will be so attached to you that in many ways they will behave as if still in your womb. Your body is your newborn’s natural habitat, and breastfeeding replaces the placenta in providing nourishment and protection.

Your baby is born with well-developed senses of taste and smell, so they will recognise your familiar scent from day one. Babies can hear when in the womb, so they will already recognise your voice too.

Your baby’s sleep pattern will seem disorganised and chaotic at first. They will usually depend on you cuddling, rocking or talking them to sleep because it’s comforting and soothing.

What is the “fourth trimester”?

These first three months after birth are a critical time often called “the fourth trimester”, a phase after pregnancy when your baby is completely helpless and dependent on you as they adapt to life outside the womb. The overwhelming new emotions you will experience when you become a mother, often intensified by lack of sleep, can make your baby’s transition from womb to world a challenging time for you too.

As soon as you become a parent, you may be given an overwhelming amount of advice regarding your newborn’s sleep. People mean well and want to be helpful, but when you’re getting a lot of this advice, you may feel your parenting skills are being judged according to your baby’s ability to sleep through the night – or not!

These supposedly ‘helpful’ tips often fail to take into account that sleep is a developmental process. Your baby’s sleep needs will change throughout their development, and in fact, throughout their entire life. Notions of how much should a baby sleep create unrealistic expectations for parents, causing unnecessary anxiety and needless worrying.

So, what should new parents know about sleep during the fourth trimester?

First weeks after birth

The first few weeks after birth can be exhausting. You have to satisfy your newborn’s every need, even if you’re sleep-deprived and still recovering from the demands of pregnancy and labour yourself. Unlike other animals, your baby cannot walk and relies on you totally for care, attention and love. They have only basic instincts and reflexes to help them control their behaviour and movement.

In the early days, you may get a lot of conflicting advice about crying, breastfeeding, sleep arrangements and basic baby care, all of which can be overwhelming and mentally exhausting. As a new mother, you will do all you can to be the best mother possible, so if others are critical you may feel yourself becoming tense, nervous or unsure of yourself. You may lose more sleep mulling over problems or endlessly searching for ‘solutions’ online and in baby books.

You’ll also be hyper-alert to your baby’s needs. You might find yourself jumping awake every time they makes a little noise, checking their breathing every few minutes, or readying yourself for the next feed even before your newborn wakes up. Getting proper rest can be really difficult.

Two things will make life easier: connecting with your baby as fully as possible (see points 2 and 3 below) and accepting help from close friends and family (or paid help, if that’s an option for you). Take full advantage when others ask to help to make your life easier, whether that’s making a cup of tea, buying groceries or collecting older siblings from nursery or school. It means you can give your full attention to looking after your baby and looking after yourself too.

Rest assured that you’ll soon become more comfortable and more confident in taking care of your baby. Little by little, you’ll start to feel more organised and both of you will begin to relax as you establish your own routine. Tiredness will still be an issue because a baby requires your care and attention day and night, but at least you will feel more in control.

Feeding your baby

Newborns have very small stomachs and need to feed frequently, so they wake at least every two to three hours – sometimes more often – for milk. As your baby grows, he or she will be able to last longer between feeds. If you’re worried about your baby getting fed enough, check out our breastmilk guide.

However, human milk is quickly digested, so babies generally feed throughout the day and night-time. All babies have different requirements, so it’s important to recognise their feeding cues (such as licking lips, sucking fingers and rooting) and feed them whenever they show you that they need it. Lansinoh has made feeding routines easier for mums with their breast pumps and breastmilk storage bags and bottles once breastfeeding is established at 4-6 weeks.

 How often do newborns sleep?

Newborn babies may sleep for 18 or so hours a day, but usually for no more than three hours at a time. During the first year, overall sleep duration falls to around 15 hours a day, and the majority of sleep becomes concentrated during night-time as your baby establishes their circadian rhythm.[1]

It can be difficult to put your baby in a cot if they prefer to sleep in your arms, so you might find a baby sling helpful. In your womb, your baby was ‘held’ by the amniotic sac, and wearing a baby sling mimics this familiar holding sensation.

Follow the guidance for safe baby-wearing, making sure you can see their face at all times, keeping them well supported and close enough to kiss, and ensuring their chin isn’t pressed towards their chest.[2]

As you go about daily activities with your baby in the sling, they will feel the movement they felt in the womb, providing comfort and reassurance. A further benefit is that, when newborn, their breathing and temperature are regulated by being in contact with you.[3] Skin-to-skin contact between mum and baby helps with bonding, making your baby feel safe and reassured.[4]

How much sleep does a 3 month old need?

Around three to four months old, your baby may start sleeping longer hours at night and will fall asleep more easily on their own, transitioning from a state of wakefulness to deep sleep more quickly, compared to the first three months when light sleep, also called REM (rapid eye movement) sleep, prevailed.

Their sleep-wake cycles will become more mature, but remember each baby is different and acts according to their own biological rhythms, so don’t force your baby to follow a particular pattern if they aren’t ready. Some babies are deep sleepers while others prefer to feed more frequently and nap instead of sleeping for long periods.

Rest assured that it’s normal for babies to wake and feed at night. According to a recent Canadian study,[5] more than half of six-month-old babies can’t sleep for eight hours in a row. Expect to have your nights interrupted during a large part of the first year. If possible, compensate by taking one or two naps during the day. Scientists have found that a daily nap is an excellent way to recuperate physically and mentally if your night-time sleep is regularly disturbed.[6]

Your baby wants to be close to you, all the time

The United Nations Children’s Fund (Unicef) recommends babies sleep in the same room as their mother for at least the first six months to make breastfeeding easier and reduce the risk of sudden infant death syndrome (SIDS). Even if you put a cot in a nursery and plan for your baby to sleep there, chances are it won’t happen. Remember, in the beginning, your baby will be like an extension of yourself, with their comfort and safety essential for your own wellbeing.

One safe possible arrangement is to attach a clip-on crib to your own bed or have a Moses basket near your bed, so you both have your own space without being apart from each other. However, there may be times when you find yourself sharing your bed with your baby (co-sleeping), especially if they can’t fall asleep unless in close contact with you.

Sleeping with your baby - do’s and don’ts

If you sleep with your baby, it’s important to follow the safety guidelines issued by leading expert organisations:[7]

  • Lay your baby to sleep on their back in a clear space on a firm, flat mattress.
  • Make sure your baby can’t fall out of bed or become trapped between the bed and wall.
  • Keep your baby away from pillows, duvets, blankets and any other items that could smother them or cause them to overheat.
  • Don’t allow pets in the bed.
  • Never leave your baby alone in an adult bed.

And never co-sleep if:

  • You or anyone else in your household smoke (even if you don’t smoke in the bedroom)
  • You or your partner have been drinking alcohol or taking any medication or drugs (legal or illegal) that could make you drowsy
  • You are on a sofa or in an armchair – this vastly increases the risk of SIDS.
  • You are particularly overtired
  • Your baby was born prematurely (before 37 weeks) or very small (under 2.5 kg or 5.5 lb).
  • Do not sleep with your baby when you have been drinking any alcohol or taking drugs that may cause drowsiness (legal or illegal).


In conclusion, it’s normal to feel a physical and emotional whirlwind following the birth of your baby. Don’t be surprised if you’re exhausted and sometimes anxious at the beginning. Being supported and well looked after by your partner, family, and friends will aid your recovery, give you confidence, and help you listen to your own inner voice – which will most likely be urging you to keep your baby close, day and night, as they transition from womb to world.

Breastfeeding and sleeping close together will help you become fully tuned to your baby, satisfying their vital need for security, warmth, safety, and nourishment.

Continuing the close connection you enjoyed during pregnancy will synchronise your inner clocks, so you will get more rest and sleep too. These first three months of helping your newborn adapt and adjust to life post-birth will seem a natural and necessary continuation of your pregnancy, enabling you to bond with your baby and find harmony together.









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