When Does a Baby's Brain Develop?

What's Going on in There?: Understanding Your Baby's Brain Growth

No wonder she needs so much sleep. As your baby coos, eats and cries, her brain is constantly growing. An infant's brain development starts soon after conception, although researchers believe a baby doesn't start to feel or think until just before birth. At birth, the brain is very much a work in progress. It undergoes rapid growth and change in your baby's first year of life. While you can't see what's happening in her brain, you'll see its progress reflected in your baby's increasing skills.

Brain Development In Utero

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What Should a 3-Month-Old Be Doing?

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Your baby's brain may already be starting to develop before you even learn you're pregnant. Of course, it doesn't start out looking or acting like a brain: it starts as what's called a neural plate, which is the beginning of your baby's nervous system. The structure starts forming just a few weeks after conception. It takes several weeks for the neural plate to develop into the neural tube, from which the brain grows.

Your baby's head starts developing around five weeks after conception, which is when the brain as we know it starts to grow. The brain continues to develop throughout the rest of the pregnancy. By the time she's born, your baby's brain should have developed around 100 billion neurons—which is all the neurons the brain needs. But despite all that rapid growth, it's only at the end of the third trimester that your baby's brain is able to perform functions like feeling and remembering.

Brain Development After Birth

Your baby's brain works hard from the first day she's born. Synapses, or connections between nerve cells, form rapidly as your baby's physical and cognitive development progresses. Essentially, her brain adds new wiring that allows her to function and thrive.

Her cerebellum undergoes rapid growth soon after birth. It's the part of the brain that controls balance and coordination, among other critical processes. Researchers at the University of California, San Diego found that babies' cerebellums doubled in size during their first three months of life. By the end of the first year, your baby's cerebellum will be three times the size it was at birth. You'll see that growth in action as you watch your baby go from a sedentary newborn to a crawling, clapping 1-year-old.

While there's a lot that scientists understand about the infant brain, there's a lot that is still unknown. But suffice it to say that your baby's brain is undergoing a tremendous amount of development in her first year of life, and especially in the first three months. The UCSD researchers found that the brains of the babies they studied grew 64 percent in just the first 90 days of life.

Helping Your Baby's Brain Develop

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Stages of Early Childhood Brain Development

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Wondering how to help your baby's brain grow and progress normally? Good news: you're probably already doing it. During pregnancy, help your baby's brain develop by abstaining from cigarettes and alcohol, eating a balanced diet and getting regular prenatal care. Once she's born, support her brain growth by talking to her frequently, being attentive to her needs and giving her a safe environment and age-appropriate toys and books to explore.

All of your baby's developmental milestones involve her brain. If she's hitting those milestones, she's probably progressing normally. Most babies are able to babble, reach for toys and hold their heads steady by 4 months old. By 6 months, your baby should be able to recognize familiar people, roll over and sit up unsupported. And by her first birthday, expect your infant to say a few words, use gestures like pointing and be able to take a few steps (or be getting close).

If your baby doesn't hit those milestones, don't panic. Premature babies may be a little behind their peers, and some perfectly healthy and normal babies just move at their own pace. But do talk to your pediatrician about any developmental concerns you have.