Everything You Need to Know About Fetal Brain Development

If you just discovered that you're pregnant, you will likely spend the next months ahead wondering how your baby is growing and developing. You might have tons of questions about fetal development and may be wondering, "When does a fetus develop a brain?"

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 with your prenatal care and get your ultrasounds, your baby will also be moving along and developing at a predictable rate.

Read on to learn how fetal brain development occurs by trimester and how you can support healthy brain development.

How Your Baby's Brain Develops by Trimester

Once you find out you are pregnant, your baby's brain is already in the works. In fact, just four weeks after conception, the foundation of your baby's brain and spinal cord is already forming.

First trimester

During those first months of pregnancy, your baby's brain and face are shaping. However, 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.

By the tenth week of pregnancy, your baby's head has become more round, and at the eleventh week, your 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, the brain stem is almost entirely developed. Your baby's brain stem controls the following:

• Heart rate
• Breathing
• Blood pressure

What's more, the fetal nervous system is developed enough that your baby will startle at loud noises outside the womb. They may even turn toward your 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. Not to mention, the formerly smooth surface of your baby's brain is becoming more and more grooved, starting to resemble the pictures of brains you are used to seeing.

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. The brain will steadily mature in response to your baby's environment.

Parts of a Baby's Brain

The human brain has five different regions that develop during pregnancy and each part of the brain serves a unique function.

Cerebrum: This part of your baby's growing brain is responsible for all the reasoning, thinking, memorizing, and feeling they will experience. It's the largest part of the brain and is where the frontal and temporal lobes are located.

Cerebellum: This part fine-tunes movement and helps with motor control, and can take time to develop in newborns.

Brain Stem: Your baby's heart rate, blood pressure, and breathing is controlled by the brain stem.

Pituitary gland: This is known as the hormone center. The pituitary gland is responsible for all things growth and plays a role in metabolism as well.

Hypothalamus: This part controls your baby's body temperature, thirst, hunger, emotions, and sleep.

Factors Impacting Fetal Brain Development

Many factors can impact fetal brain development, but most healthy people do not need to radically alter their lives to promote healthy growth. In fact, the most important factor in optimal brain growth is to live a healthy lifestyle, which includes eating a healthy diet and exercising.

While it may seem obvious, it is also important for pregnant people to eliminate alcohol and cigarettes. These substances can impair the formation and wiring of brain cells.

Infections

Overall, infections pose the greatest risk to the growing and developing baby. Most parents are immune to the most dangerous of these, which include chickenpox and measles.

However, toxoplasmosis, some sexually transmitted diseases, and cytomegalovirus are also of concern and should be discussed with a health care provider.

Stress

Some researchers believe that stress during pregnancy can impact brain growth and development. In fact, one study found that a person's stress during pregnancy changes the neural connectivity in the brain of a fetus.

Using fetal resting-state fMRI, researchers examined babies between the 30th and 37th-week gestation with people from a low-income, high-stress urban setting. Prior to the testing, many gestational parents indicated that they had high levels of depression, anxiety, worry, and stress. Consequently, the researchers found that people 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 person's stress level and fetal brain development.

Choline

Meanwhile, another study found that consuming choline, an essential nutrient found in eggs, beef, and liver, can help prevent issues with fetal brain development. Choline even helped when pregnant people were experiencing an illness such as influenza. In fact, the study found that choline supplements can prevent developmental problems in unborn babies when a gestational parent has an infection or cold.

Interestingly, prenatal vitamins usually do not contain choline. As a result, investigators concluded that supplements can help pregnant people reach the high choline levels needed by their babies. As with any supplement, though, talk to a health care provider before taking it.

How You Can Support Your Baby's Brain

Every person wants to give their 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. The most important thing is taking care of yourself.

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 a health care provider about taking choline supplements. However, do not take anything, even over-the-counter supplements, without first discussing it with them.

Get plenty of exercise

If you were not already exercising before becoming pregnant, you should talk to a health care provider before starting any exercise regimen. Typically, the following are safe options:

• Walking
• Water aerobics
• Prenatal yoga classes

Just be sure that you do not overdo it, as you don't want to risk injuring yourself or your developing baby.

Avoid toxins

Toxins are bad for anyone, including a pregnant person and their 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 the following:

• Prolonged exposure to cleaning supplies
• Poor air quality
• 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 find ways 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 will also boost language and memory skills later on, so make sure you talk to your baby on a regular basis.

Play music

There is some disagreement over whether or not playing classical music for your unborn baby will boost IQ, playing music. However, playing any kind of music for your baby is good for both of you. Not only can music relax your baby, 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. Alcohol use can lead to fetal alcohol syndrome and can interfere with the development of cognitive brain cells. In fact, drinking during pregnancy is linked to the following outcomes in offspring:

• Slow growth
• Developmental delay
• Unusual facial features
• Irritability
• Brain and neurological disorders
• Intellectual disabilities
• Problems with emotional attachment
• Lower IQs
• Poor cognitive skills
• Attention deficits
• Impulsive behavior
• Poor coordination
• Depression and anxiety

Meanwhile, nicotine reduces the blood flow and nutrition to your baby because it constricts your blood vessels and also impacts cognitive brain cells.