What is the Fourth Trimester?

  • You may not have heard of the fourth trimester but basically this is the idea that the first 3 months of life are very much an extension of life in the womb. Your baby’s fourth trimester starts from the moment they are born and lasts until they are three months old. The term is used to describe a period of great change and development in your newborn, as they adjust to their new world outside your womb.
  • Baby has spent their whole life not knowing hunger, constantly being rocked and hearing your heart beat. No wonder attempts to schedule a newborn or their sleep results in frustrations
  • Think how much they still need to develop over these next few months, from refining and developing all their senses and controlling their reflexes, to learning how to respond to you and your partner. The mental and physical strides your baby takes during the first three months are just as important to development as those taken in your womb.
  • The fourth trimester is also a time for your baby to get used to the variety of noises, lights, smells, sounds and sensations of the outside world. Moving from the familiar comfort of your warm, dark and quiet womb to a noisy, bright and often cold environment, is a major change for your baby.
  • At birth, your baby’s senses are limited and still developing. They have sight, but vision is blurred. They can hear, but it’s difficult to pick up on individual sounds and voices. They can feel, but the reassuring and snug comfort of your womb has been replaced by disconcerting open space. The fourth trimester is a time for your baby to adapt to these changes with your help and support.
  • Although your baby’s brain is well developed by the time that they are born, neural pathways and nervous system continue to develop after birth. Much of this takes place during the fourth trimester. Your baby’s brain is like a sponge, soaking up everything that happens to them. The more their brain is stimulated, the better the connections in the brain synapses will become.

In the first three months of life, you may notice your baby.

  • Gradually breathing more steadily, startling less and developing more controlled movements
  • Settling into more consistent sleep and feeding patterns
  • Being able to sleep through noise or disturbances
  • Learning to soothe herself or crying out for your attention to comfort her.
  • Improving her social skills, so she can interact with family and friends, objects or music with greater attention and for longer periods of time.


Your baby is likely to cry more during the fourth trimester than at any other time in their life. Knowing that this is completely normal can help you cope with the inevitable worry and anxiety that a crying baby brings.

Crying tends to peak at around five to six weeks, and usually eases off by the time your baby reaches three months.

Your newborn is too young to have a fixed routine, and probably won’t be ready for one until they are around three months. Until then it’s fine to feed or soothe your baby as soon as they cries. Contrary to what you may have heard from older relatives, this won’t spoil your baby. In fact, it will help her feel more secure, so they may even cry less.


Let go of sleep expectations! Sleep is probably the number one concern of new parents.  It seems like the first thing anyone asks a new mama is “Is baby a good sleeper?”  My favourite reply is “She sleeps like a baby”

Your newborn is going to sleep a lot, especially in the early weeks. Sleeping is good for them, as it helps their brain process all that wonderful sensory stimulation they’ve been receiving from you and your partner while they are awake.

But it may take a little while for your baby to settle into a sleeping routine. Coming from the constant environment of your womb, your baby has no concept of day or night yet. It will take weeks, perhaps months, for them to adjust their sleeping patterns to sleeping more hours at night. So for now, let your newborn sleep whenever they like. They’ll work out their pattern eventually.

Although it may seem odd, putting your baby down to sleep during the day in a noisy, bright environment is fine. It’s likely that they will be able to shut out this stimulation and just drift off, although not all babies can do this. You’ll soon see what works best for your baby. But it’s also not bad or wrong for baby to nap while being worn.  Wearing or holding your baby for sleep in the fourth trimester isn’t going to create “bad habits” that can’t be broken.  Babies need to sleep and babies sleep best snuggled up to loving caregivers.

Of course, Mums need to sleep too – and that’s where much of the concern over “sleeping through the night” comes from.  Adjusting your expectations about sleep may also mean changing some of your sleep habits.  If baby has its longest stretch of sleep from 8pm to midnight – maybe you need to adjust your own bedtime temporarily to take advantage of that.  Sharing a sleep space can also help with sleep deprivation since it cuts down on the amount of time you have to be awake and most likely will help baby sleep longer stretches too.  It also helps to remember that this stage won’t last for ever.  All babies will sleep longer stretches eventually.  If you let go of the expectation that your baby should sleep 8 hours or more straight by 2 or 3 months, it’s a little easier to handle those night wakings; It feels much better to consider your baby’s behaviour as “normal” instead of trying to figure out what you are doing “wrong.”


As a newborn, your baby has a small stomach, so needs feeding little and often, with at least eight feeds every 24 hours.

As you get to know your baby, you’ll begin to understand the little cues and signals they make that tell you they are hungry. It’s easy to assume that crying is the first sign that they are hungry, but it can be the last. Early signs to look out for include sucking on her fingers, turning the head and opening the mouth.

Picking up on these signs is useful for you both. If your baby reaches the point of crying, they may be too upset to latch on properly or settle down for a feed.

Don’t worry about creating “bad” habits.  You cannot spoil a newborn!   No matter how much you rock, cuddle, wear, or hold your baby, he or she is going to turn into an independent little person eventually.  Children are not spoiled by love and affection; they thrive on it.

Remember you are doing a great job and you are not alone. Babies aren’t “good” or “bad”, they are just babies.