After the birth of a baby, it can be hard to know what to expect. You may feel overwhelmed and unsure about how you should take care of your body and your baby after giving birth. This transition period, often known as the fourth trimester, is an important time for parents and their newborns alike as they adjust to life post-pregnancy. Let’s take a closer look at the details of the fourth trimester including what it means, why it’s important, and what sorts of things you might experience during this time.

What is the Fourth Trimester?

While most new parents are familiar with the three trimesters of pregnancy, the lesser-known fourth “trimester” is a transitional period of 12 weeks following the birth. This extra trimester, also known as postpartum adjustment, occurs while you heal from the intense experience of pregnancy and childbirth and simultaneously care for your newborn. Your newborn will experience many developmental changes during this time as they grow accustomed to their new surroundings.

Why is the Fourth Trimester Important?

During the first three months after birth, your newborn will continue to be fully dependent on you for care as they experience developmental changes outside of the womb. The fourth trimester is the span of time where your newborn learns to use their senses to experience the world around them. Your child will likely learn to hold their head up on their own, follow objects with their attention, and start communicating with noises during the fourth trimester. It may feel like you are simply dealing with a fussy, cranky baby for 12 weeks, but they are learning new things as every day passes.

The fourth trimester is also a critical time for parents to adjust to life post-pregnancy. The first few weeks will especially feel like a whirlwind, between bringing a new baby home, getting little sleep, and experiencing dramatic hormonal changes in your post-birth body. While this rollercoaster of emotions is normal, it’s important to be mindful and honest about your wellbeing and needs as well as those of your baby.

What to Expect With Your Newborn

Your newborn’s brain will start taking input from their new environment and make connections with their developing nervous systems. Things like new sights, sounds, tastes, and textures may be difficult for them to adjust to at first. They will start learning how to control their muscles beyond natural instincts, and the fourth trimester is often when you will first see them learn to smile. These new physical demands will result in three main things you’ll need to navigate with your newborn: feeding, sleeping, and crying.

young mom breastfeeding baby on couch


You should expect to feed your baby quite often during the fourth trimester. With whichever method of feeding you choose (breast milk/nursing, formula, or some combination of both) you will likely need to feed your newborn every 2-3 hours so they get the nutrients they need to grow. Changing a growing baby’s diapers frequently means they are getting the food they need!


While a newborn baby will need a lot of sleep (14-17 hours within a 24-hour period), their sleep schedule is often irregular and unpredictable. Your baby will likely not sleep through the night until they are about 3-4 months old, or just after the fourth trimester ends. You may need to make adjustments to your own sleep routine during this time so that you get as much rest as possible while still accommodating their needs, such as feeding and burping, changing their diapers, and cuddling them when they get fussy.


As a new parent, you are suddenly faced with the responsibility of interpreting your newborn’s frequent cries during the fourth trimester. Some common reasons for their crying could be that they are hungry, gassy, wet, uncomfortable, tired, or just want to be held. If there seems to be no obvious reason for the crying, holding and rocking your baby can help comfort them.

We often recommend trying “The 5 S’s” method, coined by Dr. Harvey Karp:

1. Swaddle – Swaddling your fussy newborn mimics the cozy environment of the womb and soothes them quite quickly. A swaddled baby also typically responds faster to the other four S’s and is less likely to startle themselves awake once they fall asleep. Be sure to swaddle correctly and only swaddle when they are fussing or sleeping.

2. Side or Stomach Position – While the back is the safest position for sleeping, it’s not the best position for soothing a baby. Try holding your newborn gently on their side or stomach until they calm down!

3. Shush – If you’ve ever fallen asleep quickly to a white noise machine or rain sounds playing from your phone, you should try something similar for your baby. White noise mimics the muffled sounds they experienced in the womb and can both calm crying and encourage sleep.

4. Swing – The fourth “S” refers to the bouncy motion your newborn felt in the womb as you went about day-to-day life activities like walking or working out. When trying to soothe your newborn’s crying, try smaller, quicker motions while holding them and supporting their neck.

5. Suck – Last but not least, sucking on a pacifier can help your newborn calm down quickly and easily.

What to Expect for New Parents

Becoming a new parent is exciting and enriching—but it can also be exhausting and discouraging at times. Not only are you adjusting to taking care of a brand new human being, but you’re also navigating your post-birth body and mental wellbeing. You will likely experience “the baby blues” for a few days or weeks after birth, which can include mood swings, crying, stress and anxiety, trouble sleeping, and problems with focusing. Being honest with your doctor during checkups is one of the most important things you can do for your own health during this time, especially if you are experiencing more intense symptoms of postpartum depression, such as:

· Severe mood swings

· Withdrawal from your partner, family, or friends

· Insomnia or excessive sleeping

· Drastic changes in appetite

· Fear or feelings of inadequacy as a parent

· Intense irritability

· Thoughts of causing yourself, your baby, or your partner harm

It is important to reach out for help from a support system or health care professional if you feel like you are struggling as a new parent. Additionally, if you are experiencing symptoms of postpartum depression or feelings of hopelessness, reach out to a professional as soon as you can.

As tiring as it can be, the fourth trimester is an important time to be present for yourself and your new baby. Take the time to prepare and build up your support system as you get ready to welcome your newborn into the world. We’re cheering for you!

Do you have more questions about the fourth trimester in Salem OregonTalk to our staff at WFMC Health or become a new patient today!

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