Helping You and Your Baby Cope with Life after Birth

After nine months of pregnancy, the uncomfortable symptoms of the third trimester, including swelling, heartburn, Braxton Hicks contractions, and frequent trips to the bathroom, leave most pregnant women eager to hold their babies in their arms. As much as moms and dads may be ready for the postpartum period to begin, newborns are not as ready to leave the comforts of the womb. This article sheds light on the “fourth trimester,” which is the first three months of a baby’s life.

What is the scientific explanation for the fourth trimester?

The human gestation period, or the development of a fetus inside a mother’s body, is 9 months or 40 weeks long. At the time of birth, a human baby’s brain is not as adequately developed when compared to other species of mammals. Researchers believe that babies may need an additional 9 to 12 months in the uterus to reach adequate brain functioning. Despite being underdeveloped, a human baby must be born at this point because head circumference begins to approach 10 centimeters. If mothers continued to carry their babies past this point, they would be unable to safely deliver them vaginally. Therefore, this theory assumes that human babies are born much earlier than they ought to be so they can secure a safe birth.

What does this mean for babies?

When you think about the fact that babies are not fully developed at birth, you can begin to understand what this must be like for them. Imagine suddenly being evicted from a comfortable, warm cocoon that you have been living in for 9 months. Researchers believe that babies are actually more like fetuses at birth, especially when compared to other mammals. For example, horses can already run when they’re born. This can explain why the first three months, or the fourth trimester, can be so trying for the less developed human baby. 

The fourth trimester can involve a lot of crying for babies. In fact up to 50% of babies under three months old cry or fuss for over two hours a day. Crying is common among newborns and does not necessarily mean that your baby is colic or that you are doing something wrong as a parent. However, it is important to talk to your baby’s pediatrician if you feel that your baby is crying for more than two hours a day,. He or she can rule out any medical explanations such as reflux.

Babies can cry for several hours per day during the first three months of life.

The Impact of the Fourth Trimester on Parents

The first three months of a baby’s life can be trying for mothers and fathers. During this time, parents are adjusting to having a new baby and may be dealing with sleep deprivation, the postpartum blues, recovery from delivery, and more. Coping with an inconsolable baby can be physically and emotionally exhausting. 

Crying itself has an evolutionary function, which is to jolt a parent into action to attend to the baby’s needs, whether it be food, diaper change, or pain. As a result, the parent’s body reacts by increasing heart rate, which can trigger anxiety. From an emotional standpoint, parents may blame themselves for their baby’s crying. A crying baby may conflict with the fantasy of having the “perfect” baby. This can have a domino effect, as stress can lead to difficulty breastfeeding, depression, and marital conflict. 

How to Help Your Baby Cope with the Fourth Trimester

Thinking about your baby as being born too early can help you focus your attention on recreating the soothing environment of the womb. While in the womb, babies are frequently rocked by their mother’s movements, snuggled by the walls of the uterus, and exposed to loud sounds. In his book “The Happiest Baby on the Block,” Dr. Harvey Karp shares techniques on how to promote the calming reflex in babies. It’s suggested that following these practices can help reduce crying. In fact, certain cultures do not experience colic because their focus is on recreating the feeling of being in the womb through constant holding, rocking, and feeding. 

Mothers around the world have found ways to soothe their babies.

To recreate the atmosphere of the womb, Dr. Karp suggests 5 techniques, called the 5 S’s, which include:


This practice mimics the closeness of the womb and can prevent the startling response. Proper swaddling involves wrapping the arms snug to the sides, but allowing the hips to remain loose. It is important to be mindful of overheating and limit swaddling to soothing fussiness and for sleep, rather than as an all-day solution. 

Side or stomach position

It is recommended to put babies to sleep ONLY on their backs in order to reduce the risk of Sudden Infant Death Syndrome (SIDS).  While the back position is best for sleep, babies may struggle to be soothed in this position. To promote the calming reflex while awake, hold a baby on his or her side or stomach. 


During gestation, babies are exposed to loud “shushing” sounds that resemble a fan or vacuum cleaner. White noise is an effective tool for mimicking the sounds present in the womb. You can find white noise available on YouTube, various apps, or purchase a white noise machine. 


It is probably no surprise that babies find swinging to be soothing. This is because the rocking motion is a part of life in the womb. Dr. Karp suggests fast, tiny movements to calm a crying baby.


Babies become accustomed to sucking on their fingers in the womb, because their position in the uterus makes it easier to reach their mouths. However, as newborns they struggle to coordinate their hand movements, making it difficult to get the pleasurable sucking sensation. Allowing a baby to suck while nursing or feeding or offering a pacifier can promote relaxation. 

How to Help Yourself Cope with the Fourth Trimester

The fourth trimester is not only a difficult adjustment for babies, but their parents as well. Here are some tips for easing the challenges of the fourth trimester:

Limit the demands that you put on yourself and set realistic goals during this period.

This is not the time to take on new projects or expect yourself to do your spring cleaning. Your main job is to “eat, sleep, and feed the baby.” Anything else can wait until after the fourth trimester passes. 

Be receptive to help.

As much as you feel comfortable, allow others to help you care for the baby and complete household tasks. Consider being direct about what help you need, since loved ones may be reluctant to overstep their bounds.

Prioritize sleep.

This can involve hiring a night nurse, having friends or family watch the baby while you nap, or simply sleeping while the baby sleeps. Give yourself permission to let other household chores slide so that you can get the rest that your body needs. 

Brainstorm baby-friendly self-care activities.

Participating in activities that are enjoyable to you is important during this time period. For example, consider taking a walk with the stroller, spending a few minutes practicing mindfulness, reading a book while you nurse, or connecting with loved ones, You may not be able to do all the self-care activities that you once could, but try your best to do what you can within the limits of your new role as a parent. 

The fourth trimester is a temporary transitional period.

The fourth trimester is a time of mixed emotions – happiness, exhaustion, and overwhelm. It’s a period of significant transition for you and your baby. Like any transition, all parties will eventually adjust and will settle into the “new normal.” When it gets difficult, remember “this too shall pass.” 


Karp, H. (2015). The happiest baby on the block: The new way to calm crying and help your newborn baby sleep longer (revised, updated). New York, NY: Bantam.

Karp, H. (2004). The “fourth trimester”. Contemporary Pediatrics, 21(2), 94-104.