Everything You Need to Know About Fetal Brain Development

What You Can Do to Support This Growth

Woman holding ultrasound photo

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If you just discovered that you're pregnant, you will likely spend the next months ahead wondering how your baby is growing and developing. Questions like: "What color will my baby's eyes be?" or "When can my baby hear me?" may run through your mind. You may even wonder about your baby's brain development.

Fortunately, fetal brain development typically follows a pretty predictable schedule. In fact, the fetal nervous system, or your baby's brain and spinal cord, is one of the first systems to develop. So, as you continue along with your prenatal care and get your ultrasounds, your baby also will be moving along and developing at a predictable rate.

Your Baby's Brain

Before you can fully understand fetal brain development, it is important to understand the different parts of your baby's brain. Overall, there are five different regions of the brain that scientists are familiar with. These include the cerebrum, cerebellum, brain stem, pituitary gland, and hypothalamus.

The cerebrum is the largest part of the brain. It is responsible for thoughts, feelings, and memories. The cerebral cortex, including the frontal and temporal lobes, is part of this area. Meanwhile, the cerebellum is the part of the brain in charge of motor control, while the brain stem is the part that controls your baby's most vital functions including heart rate, breathing, and blood pressure.

The pituitary gland is the pea-sized gland that releases hormones into your baby's body. These hormones are responsible for growth and metabolism. And, the hypothalamus is the part of your baby's brain that is in charge of body temperature, hunger, thirst, sleep, and emotions. Even though these parts of the brain are developing at a rapid rate while in the womb, there is still a great deal of development that will take place outside of your body as well.

How Your Baby's Brain Develops

Once you find out you are pregnant, your baby's brain is already in the works. In fact, just four weeks after conception, the neural plate forms, which is the foundation of your baby's brain and spinal cord. As it grows longer, it folds in on itself until that fold changes into a groove. Eventually, that groove will turn into the neural tube. This neural tube, located along your baby's back, is important to your baby's brain and spinal cord development, which both develop from the neural tube.

First Trimester

Around seven weeks into your pregnancy, your baby's brain and face are growing. Additionally, once the neural tube closes, it will curve and bulge into three sections commonly referred to as the forebrain, midbrain, and hindbrain. Just behind the hindbrain is the part that will eventually turn into your baby's spinal cord. Soon, these areas of the brain will become the five different regions of the brain including the cerebrum, cerebellum, brain stem, pituitary gland, and hypothalamus. Depressions that will eventually become your baby's nostrils also are visible and the beginnings of the retinas are forming too.

Even though your baby is developing specific sections of the brain, it is not until around week six that the first electrical brain activity begins to occur. This activity represents your baby's first synapses, which means your baby's neurons can communicate.

However, this activity is still very primitive and consists of the unorganized firing of neurons. By the tenth week of pregnancy, your baby's head has become more round; and at the eleventh week you baby's head still makes up about half of its length. Soon though, the body will catch up.

Second Trimester

During the second trimester, your baby's brain is directing the diaphragm and chest muscles to contract, which is a lot like practice breathing. It is also around this time that your baby learns its first sucking and swallowing impulses. In fact, by 21 weeks, your baby's natural swallowing reflexes allow several ounces of amniotic fluid to be swallowed every day. That means, your baby is also tasting every time swallowing happens.

By the end of the second trimester, your baby's brain stem, which controls heart rate, breathing, and blood pressure, is almost entirely developed and rests just above the spinal cord and below the cerebral cortex. What's more, the fetal nervous system is developed enough that your baby will startle at loud noises outside the womb. Your baby may even turn toward your voice or your partner's voice at this point. And, by 28 weeks, fetal brainwave activity features sleep cycles including REM sleep where dreaming usually occurs.

Third Trimester

During the third trimester, your baby's brain almost triples in weight; and there also is rapid development of neurons and wiring. What's more, the formerly smooth surface of your baby's brain is becoming more and more grooved and starting to resemble the pictures of brains you are used to seeing. Meanwhile, the cerebellum is developing very quickly. In fact, it is developing faster than any other area of your baby's brain.

By the time your baby is born, the brain largely resembles that of an adult brain. But, it is important to remember that it is far from finished with development. Putting down the infrastructure for a mature brain and having a mature brain are not the same thing. For instance, even though the cerebral cortex develops rapidly in the womb, it really does not start to function until a full-term baby is born. Then, it steadily matures in response to your baby's environment.

Factors Impacting Fetal Brain Development

There are many factors that can impact fetal brain development, but most healthy women do not need to radically alter their lives in order to promote healthy fetal brain development. In fact, the most important factor in optimal brain growth is to live a healthy lifestyle, which includes eating a healthy diet and exercising. It is also important for pregnant women to eliminate alcohol and cigarettes because these substances can impair the formation and wiring of brain cells.

Infections

Overall, infections pose the greatest risk to the growing and developing baby. But most moms are immune to the most dangerous of these, which include chickenpox and measles. However, toxoplasmosis, some sexually-transmitted diseases, and cytomegalovirus also are of concern and should be discussed with your doctor.

Stress

So, what about other factors in your life like stress? Do they also impact fetal brain development? Some researchers believe that stress can impact brain growth and development. In fact, one study found that a mother's stress during pregnancy changes the neural connectivity in the brain of her unborn child.

Using fetal resting-state fMRI, researchers examined babies between the 30th and 37th-week gestation with moms from a low-income, high-stress urban setting. Prior to the testing, many of the moms indicated that they had high levels of depression, anxiety, worry, and stress. Consequently, what the researchers found is that mothers reporting high levels of stress had fetuses with reduced efficiency in how their neural functional systems were organized.

This study is the first time imaging has shown a direct connection between a mother's stress level and fetal brain development. What's more, the researchers found that the cerebellum played a central role in the effects that they observed. As a result, this part of the growing baby's brain may be more vulnerable to the effects of early life stress than originally thought.

Choline

Meanwhile, another study from the University of Colorado found that consuming choline, an essential nutrient found in eggs, beef, and liver, can help prevent issues with fetal brain development, even when pregnant moms are suffering from an illness such as influenza. In fact, the study found that choline supplements can prevent developmental problems in unborn babies when mom has an infection or cold.

Additionally, researchers found that at one year of age, babies whose moms experienced an infection and had lower choline levels had babies with a dramatically reduced ability to pay attention, play quietly, and cuddle with their parents. None of these effects occurred though when the mom had higher levels of choline in her system.

Interestingly, prenatal vitamins usually do not contain choline. As a result, investigators concluded that supplements, which are recommended by the American Medical Association, can help expectant mothers reach the high choline levels needed by their babies. As with any supplement though, talk to your doctor before taking it.

How You Can Support Your Baby's Brain

Every mother wants to give her baby the best possible start in life. But sometimes it can be difficult to know what to do, especially with so much advice floating around in books, magazines and on the Internet. Just listen to your doctors and follow their advice and you should be fine. Most likely, they will suggest these simple tips to keep both you and your baby healthy.

Feed Your Body

When you eat healthy foods, drink plenty of water, and take your prenatal vitamins, you are giving your baby's developing brain the nourishment it needs for optimal growth. You may even want to talk to your doctor about taking choline supplements; but do not take anything, even over the counter supplements, without first talking with your doctor.

Get Plenty of Exercise

If you were not already exercising before becoming pregnant, you should talk to your doctor before starting any exercise regimen. But typically, walking, water aerobics, and prenatal yoga classes are safe options. Just be sure that you do not overdo it. You don't want to risk injuring yourself or your developing baby.

Avoid Toxins

Toxins are bad for anyone including a pregnant mom and her unborn baby. Fortunately, avoiding toxins in the environment is fairly easy unless you work for a dry-cleaning company, on a farm, or in a factory, in which case you can request to be moved to a less toxic area of the business.

Overall, you should avoid prolonged exposure to cleaning supplies, pay attention to air quality alerts, and avoid pollutants from heavy traffic. But, do not stress about the things you cannot control. Just do your best and do not expose yourself to chemicals unnecessarily.

Manage Your Stress

There are countless studies that connect high stress levels in pregnancy with adverse fetal brain development. As a result, do everything you can to reduce the stress in your life. Lighten your workload and learn how to relax. One way to reduce stress is to focus on various relaxation techniques such as breathing exercises, journaling, and meditation.

Talk to Your Baby Bump

Research shows that when you talk to your baby in the womb, you are doing more than just building a connection. You also are laying the foundation for their social and emotional development. These one-way conversations also will boost language and memory skills down the road. So, make sure you are talking to your baby on a regular basis.

Play Music

While there is some disagreement over whether or not playing Mozart for your unborn baby will boost IQ, playing music, in general, is good for both of you. Not only can music, especially classical music, be relaxing, but it also can help your unborn baby learn new sounds and tones.

Give Up Alcohol and Smoking

Never smoke or drink while you are pregnant. For instance, alcohol use can lead to fetal alcohol syndrome. It also can interfere with the development of cognitive brain cells. In fact, drinking during pregnancy often leads to lower IQs, poor cognitive skills, attention deficits, impulsive behavior, and even poor coordination. Meanwhile, nicotine reduces the blood flow and nutrition to your baby because it constricts your blood vessels. It also impacts cognitive brain cells.

A Word From Verywell

When it comes to fetal brain development, the best thing you can do to support your baby's brain development and growth is to live a healthy lifestyle. This includes eating right, exercising, getting plenty of sleep, and reducing stress levels. If you are worried about your diet or your stress levels, talk to your doctor. There are things you can do today to help you get on the right track to ensure your baby's brain grows and develops as it should.

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Article Sources

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  • "Prenatal stress changes brain connectivity in-utero: New findings from developmental cognitive neuroscience." Cognitive Neuroscience Society, ScienceDaily, March 2018. www.sciencedaily.com/releases/2018/03/180326110123.htm

  • Freedman MD, Robert et al. "Higher Gestational Choline Levels in Maternal Infection Are Protective for Infant Brain Development." Journal of Pediatrics, May 2019. doi: https://doi.org/10.1016/j.jpeds.2018.12.010