Different stages of baby development

Baby Development Stages: The First Year

Written by Gina Shaw

From helpless newborn to active toddler: It takes just 12 short months for your baby to undergo this incredible transformation. Babies grow and change at an astounding pace, and every month brings new and exciting developments.

New moms and dads often wonder what to expect next and how to know if their baby’s development is on target. Instead of focusing too much on developmental milestones, however, it’s important to remember that babies all develop at their own pace. There’s a fairly wide “window” for when it is normal for a baby to reach a particular developmental stage.

“If your baby reaches one milestone sooner, she may reach another one later, because she’s so busy perfecting the other skill,” says Jennifer Shu, MD, pediatrician and co-author of Heading Home with Your Newborn.

Some babies may say their first word at eight months, while others don’t talk until a little after the one-year mark. And walking may start anytime between nine and 18 months.

Keeping those kinds of variations in mind, here’s what your baby may be doing during each three-month stage of the first year.

Baby Development: One to Three Months

During this first development stage, babies’ bodies and brains are learning to live in the outside world. Between birth and three months, your baby may start to:

• Smile. Early on, it will be just to themselves. But within three months, they’ll be smiling in response to your smiles and trying to get you to smile back at them.
• Raise their head and chest when on their tummy.
• Track objects with their eyesand gradually decrease eye crossing.
• Open and shut their hands and bring hands to their mouth.
• Grip objects in their hands.
• Take swipes at or reach for dangling objects, though they usually won’t be able to get them yet.

Baby Development: Four to Six Months

During these months, babies are really learning to reach out and manipulate the world around them. They’re mastering the use of those amazing tools, their hands. And they’re discovering their voices. From 4 to 6 months old, your baby will probably:

• Roll over from front to back or back to front. Front-to-back usually comes first.
• Babble, making sounds that can sound like real language.
• Laugh.
• Reach out for and grab objects (watch out for your hair), and manipulate toys and other objects with their hands.
• Sit up with support and have great head control.

Baby Development: Seven to Nine Months

During the second half of this year, your little one becomes a baby on the go. After learning that they can get somewhere by rolling over, they’ll spend the next few months figuring out how to move forward or backward. If you haven’t baby-proofed yet, better get on it!

• During this time period, your baby may:
• Start to crawl. This can include scooting (propelling around on their bottom) or “army crawling” (dragging themselves on their tummy by arms and legs), as well as standard crawling on hands and knees. Some babies never crawl, moving directly to from scooting to walking.
• Sit without support.
• Respond to familiar words like their name. They may also respond to “No” by briefly stopping and looking at you, and may start babbling "Mama" and "Dada."
• Clap and play games such as patty-cake and peekaboo.
• Learn to pull up to a standing position.

Baby Development: 10 to 12 Months

The last development stage in baby’s first year is quite a transition. They aren’t an infant anymore, and they might look and act more like a toddler. But they are still a baby in many ways. They are learning to:

• Begin feeding herself. Babies at this developmental stage master the “pincer grasp“ -- meaning they can hold small objects such as O-shaped cereal between their thumb and forefinger.
• Cruise, or move around the room on their feet while holding onto the furniture.
• Say one or two words, and "Mama" and "Dada" become specific name for parents. The average is about three spoken words by the first birthday, but the range on this is enormous.
• Point at objects they want in order to get your attention.
• Begin “pretend play” by copying you or using objects correctly, such as pretending to talk on the phone.
• Take their first steps. This usually happens right around one year, but it can vary greatly.

Your Baby’s Development: When to Talk to a Pediatrician

What should you do if you think your baby is not meeting growth or developmental milestones, when they should? First, says Shu, trust your instincts. “If you really feel like something’s wrong, then talk to your doctor about it because if there is a problem, we want to catch it as soon as we can," she says. "Early intervention is best, and you know your child better than anyone.”

Remember, however, that it is not exactly when your baby sits up by themselves or says their first words that is important; it’s that they are moving forward in their development. “Don’t look at the time as much as the progression, and see that your child is changing and growing,” says Shu. “It’s not a race. Nobody’s going to ask on a college application when your child first walked or said ‘da-da.’”

Your Child’s Development -- Month by Month

This table shows common developmental milestones that babies reach each month during their first year, in four major categories. Keep in mind that all babies are different and every baby grows at their own pace. There's no precise time that most of these skills first appear. If your child hasn’t reached a milestone by the month it is listed on this chart, it is usually a perfectly normal variation in child development. Watch for progress, not deadlines.

Fetal development: Month-By-Month Stages of Pregnancy

When does a pregnancy start?

The start of pregnancy is actually the first day of your last menstrual period. This is called the gestational age, or menstrual age. It’s about two weeks ahead of when conception actually occurs. Though it may seem strange, the date of the first day of your last period will be an important date when determining your due date. Your healthcare provider will ask you about this date and will use it to figure out how far along you are in your pregnancy.

How does conception work?

Each month, your body goes through a reproductive cycle that can end in one of two ways. You will either have a menstrual period or become pregnant. This cycle is continuously happening during your reproductive years — from puberty in your teen years to menopause around age 50.

In a cycle that ends with pregnancy, there are several steps. First, a group of eggs (called oocytes) gets ready to leave the ovary for ovulation (release of the egg). The eggs develop in small, fluid-filled cysts called follicles. Think of these follicles as small containers for each immature egg. Out of this group of eggs, one will become mature and continue on through the cycle. This follicle then suppresses all the other follicles in the group. The other follicles stop growing at this point.

The mature follicle now opens and releases the egg from the ovary. This is ovulation. Ovulation generally happens about two weeks before your next menstrual period begins. It’s generally in the middle of your cycle.

After ovulation, the opened (ruptured) follicle develops into a structure called the corpus luteum. This secretes (releases) the hormones progesterone and estrogen. Progesterone helps prepare the endometrium (lining of the uterus). This lining is the place where a fertilized egg settles to develop. If you don’t become pregnant during a cycle, this lining is what is shed during your period.

On average, fertilization happens about two weeks after your last menstrual period. When the sperm penetrates the egg, changes occur in the protein coating of the egg to prevent other sperm from entering.

At the moment of fertilization, your baby’s genetic make-up is complete, including its sex. The sex of your baby depends on what sperm fertilizes the egg at the moment of conception. Generally, women have a genetic combination of XX and men have XY. Women provide each egg with an X. Each sperm can be either an X or a Y. If the fertilized egg and sperm is a combination of an X and Y, it’s a boy. If there are two Xs, it’s a girl.

What happens right after conception?

Within 24 hours after fertilization, the egg begins rapidly dividing into many cells. It remains in the fallopian tube for about three days after conception. Then the fertilized egg (now called a blastocyte) continues to divide as it passes slowly through the fallopian tube to the uterus. Once there, its next job is to attach to the endometrium. This is called implantation.

Before implantation though, the blastocyte breaks out of its protective covering. When the blastocyte makes contact with the endometrium, the two exchange hormones to help the blastocyte attach. Some women notice spotting (slight bleeding) during the one or two days when implantation happens. This is normal and isn’t something you should worry about. At this point, the endometrium becomes thicker and the cervix (the opening between your uterus and birth canal) is sealed by a plug of mucus.

Within three weeks, the blastocyte cells ultimately form a little ball, or an embryo. By this time, the first nerve cells have formed.

Your developing fetus has already gone through a few name changes in the first few weeks of pregnancy. Generally, it's called an embryo from conception until the eighth week of development. After the eighth week, it's called a fetus until it’s born.

How early can I know I’m pregnant?

From the moment of conception, the hormone human chorionic gonadotrophin (hCG) will be present in your blood. This hormone is created by the cells that form the placenta (food source for the growing fetus). It’s also the hormone detected in a pregnancy test. Even though this hormone is there from the beginning, it takes time for it to build within your body. It typically takes three to four weeks from the first day of your last period for the hCG to increase enough to be detected by pregnancy tests.

When should I reach out to my healthcare provider about a new pregnancy?

Most healthcare providers will have you wait to come in for an appointment until you have had a positive home pregnancy test. These tests are very accurate once you have enough hCG circulating throughout your body. This can be a few weeks after conception. It’s best to call your healthcare provider once you have a positive pregnancy test to schedule your first appointment.

When you call, your healthcare provider may ask you if you are taking a prenatal vitamin. These supplements contain folic acid. It’s important that you get at least 400mcg of folic acid each day during a pregnancy to make sure the fetus's neural tube (beginning of the brain and spine) develops correctly. Many healthcare providers suggest that you take prenatal vitamins with folic acid even when you aren’t pregnant. If you weren’t taking prenatal vitamins before your pregnancy, your provider may ask you to start as early as possible.

What’s the timeline for fetal development?

The fetus will change a lot throughout a typical pregnancy. This time is divided into three stages, called trimesters. Each trimester is a set of about three months. Your healthcare provider will probably talk to you about fetal development in terms of weeks. So, if you are three months pregnancy, you are about 12 weeks.

You will see distinct changes in the fetus, and yourself, during each trimester.

Traditionally, we think of a pregnancy as a nine-month process. However, this isn’t always the case. A full-term pregnancy is 40 weeks, or 280 days. Depending on what months you are pregnant during (some are shorter and some longer) and what week you deliver, you could be pregnant for either nine months or 10 months. This is completely normal and healthy.

Once you get close to the end of your pregnancy, there are several category names you might hear regarding when you go into labor. These labels divide up the last few weeks of pregnancy. They’re also used to look out for certain complications in newborns. Babies that are born in the early term period or before may have a higher risk of breathing, hearing or learning issues than babies born a few weeks later in the full term time frame. When you’re looking at these labels, it’s important to know how they’re written. You may see the week first (38) and then you’ll see two numbers separated by a slash mark (6/7). This stands for how many days you currently are in the gestational week. So, if you see 38 6/7, it means that you are on day 6 of your 38th week.

The last few weeks of pregnancy are divided into the following groups:

• Early term: 37 0/7 weeks through 38 6/7 weeks.
• Full term: 39 0/7 weeks through 40 6/7 weeks.
• Late term: 41 0/7 weeks through 41 6/7 weeks.
• Post term: 42 0/7 weeks and on.

Talk to your healthcare provider about any questions you may have about gestational age and due date.

Stages of Growth Month-by-Month in Pregnancy

First trimester

The first trimester will span from conception to 12 weeks. This is generally the first three months of pregnancy. During this trimester, the fertilized egg will change from a small grouping of cells to a fetus that is starting to have a baby’s features.

Month 1 (weeks 1 through 4)

As the fertilized egg grows, a water-tight sac forms around it, gradually filling with fluid. This is called the amniotic sac, and it helps cushion the growing embryo.

During this time, the placenta also develops. The placenta is a round, flat organ that transfers nutrients from the mother to the fetus, and transfers wastes from the fetus. Think of the placenta as a food source for the fetus throughout your pregnancy.

In these first few weeks, a primitive face will take form with large dark circles for eyes. The mouth, lower jaw and throat are developing. Blood cells are taking shape, and circulation will begin. The tiny "heart" tube will beat 65 times a minute by the end of the fourth week.

By the end of the first month, the fetus is about 1/4 inch long – smaller than a grain of rice.

Month 2 (weeks 5 through 8)

Facial features continue to develop. Each ear begins as a little fold of skin at the side of the head. Tiny buds that eventually grow into arms and legs are forming. Fingers, toes and eyes are also forming.

The neural tube (brain, spinal cord and other neural tissue of the central nervous system) is well formed now. The digestive tract and sensory organs begin to develop too. Bone starts to replace cartilage.

The head is large in proportion to the rest of the body at this point. At about 6 weeks, a heartbeat can usually be detected.

After the 8th week, healthcare providers refer to it as a fetus instead of an embryo.

By the end of the second month, the fetus is about 1 inch long and weighs about 1/30 of an ounce.

Month 3 (weeks 9 through 12)

The arms, hands, fingers, feet and toes are fully formed. At this stage, the fetus is starting to explore a bit by doing things like opening and closing its fists and mouth. Fingernails and toenails are beginning to develop and the external ears are formed. The beginnings of teeth are forming under the gums. The reproductive organs also develop, but sex is still difficult to distinguish on ultrasound.

By the end of the third month, the fetus is fully formed. All the organs and limbs (extremities) are present and will continue to develop in order to become functional. The circulatory and urinary systems are also working and the liver produces bile.

At the end of the third month, the fetus is about 4 inches long and weighs about 1 ounce.

Since the most critical development has taken place, your chance of miscarriage drops considerably after three months.

Second trimester

This middle section of pregnancy is often thought of as the best part of the experience. By this time, any morning sickness is probably gone and the discomfort of early pregnancy has faded. The fetus will start to develop facial features during this month. You may also start to feel movement as the fetus flips and turns in the uterus. During this trimester, many people find out whether their baby will be designated male or female at birth. This is typically done during an anatomy scan (an ultrasound that checks physical development) around 20 weeks.

Month 4 (weeks 13 through 16)

The fetal heartbeat may now be audible through an instrument called a doppler. The fingers and toes are well-defined. Eyelids, eyebrows, eyelashes, nails and hair are formed. Teeth and bones become denser. The fetus can even suck his or her thumb, yawn, stretch and make faces.

The nervous system is starting to function. The reproductive organs and genitalia are now fully developed, and your doctor can see on ultrasound if the fetus will be designated male or female at birth.

By the end of the fourth month, the fetus is about 6 inches long and weighs about 4 ounces.

Month 5 (weeks 17 through 20)

At this stage, you may begin to feel the fetus moving around. The fetus is developing muscles and exercising them. This first movement is called quickening and can feel like a flutter.

Hair begins to grow on the head. The shoulders, back and temples are covered by a soft fine hair called lanugo. This hair protects the fetus and is usually shed at the end of your baby's first week of life.

The skin is covered with a whitish coating called vernix caseosa. This "cheesy" substance is thought to protect fetal skin from the long exposure to the amniotic fluid. This coating is shed just before birth.

By the end of the fifth month, the fetus is about 10 inches long and weighs from 1/2 to 1 pound.

Month 6 (weeks 21 through 24)

If you could look inside the uterus right now, you would see that the fetus's skin is reddish in color, wrinkled and veins are visible through translucent skin. The finger and toe prints are visible. In this stage, the eyelids begin to part and the eyes open.

The fetus responds to sounds by moving or increasing the pulse. You may notice jerking motions if the fetus hiccups.

If born prematurely, your baby may survive after the 23rd week with intensive care.

By the end of the sixth month, the fetus is about 12 inches long and weighs about 2 pounds.

Month 7 (weeks 25 through 28)

The fetus continues to mature and develop reserves of body fat. At this point, hearing is fully developed. The fetus changes position frequently and responds to stimuli, including sound, pain and light. The amniotic fluid begins to diminish.

If born prematurely, your baby would be likely to survive after the seventh month.

At the end of the seventh month, the fetus is about 14 inches long and weighs from 2 to 4 pounds.

Third trimester

This is the final part of your pregnancy. You may be tempted to start the countdown till your due date and hope that it would come early, but each week of this final stage of development helps the fetus prepare for birth. Throughout the third trimester, the fetus gains weight quickly, adding body fat that will help after birth.

Remember, even though popular culture only mentions nine months of pregnancy, you may actually be pregnant for 10 months. The typical, full-term pregnancy is 40 weeks, which can take you into a tenth month. It’s also possible that you can go past your due date by a week or two (41 or 42 weeks). Your healthcare provider will monitor you closely as you approach your due date. If you pass your due date, and don’t go into spontaneous labor, your provider may induce you. This means that medications will be used to make you go into labor and have the baby. Make sure to talk to your healthcare provider during this trimester about your birth plan.

Month 8 (weeks 29 through 32)

The fetus continues to mature and develop reserves of body fat. You may notice more kicking. The brain developing rapidly at this time, and the fetus can see and hear. Most internal systems are well developed, but the lungs may still be immature.

The fetus is about 18 inches long and weighs as much as 5 pounds.

Month 9 (weeks 33 through 36)

During this stage, the fetus continues to grow and mature. The lungs are close to being fully developed at this point.

The fetus has coordinated reflexes and can blink, close the eyes, turn the head, grasp firmly, and respond to sounds, light and touch.

The fetus is about 17 to 19 inches long and weighs from 5 ½ pounds to 6 ½ pounds.

Month 10 (Weeks 37 through 40)

In this final month, you could go into labor at any time. You may notice that less movement because space is tight. At this point, The fetus's position may have changed to prepare for birth. Ideally, it's head down in your uterus. You may feel very uncomfortable in this final stretch of time as the fetus drops down into your pelvis and prepares for birth.

Your baby is ready to meet the world at this point. They are about 18 to 20 inches long and weigh about 7 pounds.

Child Development Calendar from the Health of the Nation

The Child Development Calendar from the Health of the Nation medical center is a convenient system that tells parents by months how the baby is developing.

Child development by months

Newborn

How does the baby behave in the first weeks of life? Should I be worried if he sleeps 18 hours a day? What you need to know about the features of feeding the crumbs, and what recommendations for care should be followed?

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1 month

What happens to a child at the age of one month, how his behavior changes. Features of development and the emergence of new actions. What you need to know about nutrition, daily care. Planned visits to doctors and testing.

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2 months

What happens in the life of a child at the age of 2 months? What behaviors should be taken into account? The appearance of the first emotions of the baby, the development of the vocal apparatus.

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3 months

What discoveries do parents expect when a child turns 3 months old? The emergence of new skills, the first conscious manifestation of emotions and desires. What you need to know about the features of feeding?

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4 months

What happens to a 4 month old baby? The first serious games and interaction with the outside world. What you need to know about the features of feeding, and what recommendations for care should be followed?

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5 months

Transition period from horizontal position. What you need to know about the features of feeding crumbs? What should parents of a five-month-old baby be prepared for?

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6 months

What did the baby learn at 6 months of age? How critical is the discrepancy with accepted norms? What you need to know about the features of feeding crumbs, how to introduce the first complementary foods?

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7-9 months

What happens to a child aged 7-9 months? The baby begins to sit, crawl or even take the first steps. The first attempts to speak appear. Toys are used in a new capacity.

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10-12 months

How does a 10-12 month old baby behave? How does his daily routine change and what games will be more interesting to play closer to the first birthday?

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12-15 months

How does a 12-15 month old child behave? What has changed in behavior, and what features of development is important to remember?

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15-18 months

How does the child behave at the age of 15-18 months? What you need to know about the features of behavior, what to pay attention to?

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18-24 months

How does a child aged 18-24 months behave? What did the baby learn in 2 years? How to make a diet?

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The main stages of a child’s mental development from 0 to 18 years old

The types of activities that a child is engaged in are varied: he draws with enthusiasm, sculpts, constructs, learns to read, sing, count, makes something, helps, plays . And each of these species contributes to its development. Of particular importance is the so-called "leading activity", which dominates at each stage. The special role of this activity is explained by the contribution to the formation of the most important changes in the psyche, to preparation for the next age period, to changes in the personality of the child. Each age has its own leading activity.

The task of parents is to reasonably manage it, providing the most favorable conditions and prospects for the further harmonious development of the child.

INFANTITY (from 0 to 1 year)

• A "social smile" (ie a smile in a social situation) may appear at the beginning of the 2nd month of life.
• Vocalizations, the child hums, gurgles, babbles, vocalizes towards an adult, demonstrates motor reactions, animation.
• From the age of 2 months, one of the most important activities for a baby is communication with a close adult.
• Sense of smell, taste, tactile sensitivity, hearing and vision develop intensively.
• During the entire first year, the child actively develops fine and gross motor skills: by 6 months, the child can grab objects, reach for toys that are interesting for him, shift the object from one hand to another, the baby can raise his head, roll over on his side and stomach from the position lie on your back.
• Crawling improves from 9 to 12 months, the baby can pull himself up on his hands to get up, learn to stand with support; by 10 months, the child can walk, holding on to a support with both hands and spreading his legs wide, by 12 months, he learns to overcome a short distance without support.

Leading activity

Emotional communication with mom, dad (or with an adult who replaces her).

How to develop

It is especially important to satisfy the child's need for caress, attention, goodwill: to love, babysit, mess around, kiss, amuse, stroke, hug, carry in your arms, press to your chest, cherish, rock, cradle.

EARLY CHILDHOOD (from 1 to 3 years)

• Speech develops actively, vocabulary expands, speaks in short sentences, words can have a “fancy” form (generate new words).
• Actively explores the world around him: he wants to touch everything, turn it over in his hands.
• Communication with relatives and familiar adults is emotionally colored: it shows joy, openness.
• Shy about a stranger, may not make contact for a long time, jealous of another child.
• They cannot hold their attention for a long time, are easily distracted, quickly forget about what is happening.
• Get tired quickly.
• Available toys: pyramids, cubes, balls, games for the development of fine motor skills.

Leading activity

Subject-handling. Development of memory, attention, speech, thinking, perception.

How to develop

To involve in household chores, observe nature together, teach manipulation with objects (use them for other purposes).

PRESCHOOL CHILDHOOD (from 3 to 6 years old)

• Words appear in the child's speech: “I want”, “I don't want”, “why?”, “I myself” (crisis of three years).
• Possesses great curiosity and imagination.
• The child begins to think in the mind (correlates action and result).
• An adult acts as a standard of behavior in various situations.
• Limited conception of time and space.
• The leading type of activity is a plot-role-playing game (simulates reality).
• Development of design and drawing skills.
• Available toys/games: dolls, soft toys, building blocks, plasticine/paints/pencils.

Leading activity

Role play, combining communication and objective activity.

How to develop

Play with your child, invent and participate in role-playing games.

JUNIOR SCHOOL AGE (from 6 to 11 years old)

• Intensive development of the intellectual and speech sphere.
• Development of voluntary attention and memory, orientation in the environment.
• The ability to act according to the model, according to the rules.
• Striving for self-assertion and recognition from adults and peers
• Actively learns communication skills, the ability to establish and maintain friendly contacts
• Self-control skills are formed
• Role identification
• Available games: educational board games, mobile games and electronic games

Leading activities

Operational and technical activities, mainly educational

How to develop

Spending time with a child, teaching him something, learning the alphabet, learning to write and count, read, retell. Help the child with the preparation of homework, answer his questions.

ADOLESCENT (11 to 14 years old)

• Seeking to communicate with peers (grouping)
• "Nihilism" in relation to adults (striving for leadership, release from care of relatives, frequent conflicts: provocative, defiant behavior)
• Fatigue
• Emotional lability
• Puberty, increased interest in the opposite sex
• Fixation on the outside (body, clothing, etc. )
• Emancipation: desire to imitate adults (experimentation)
• Begins to form its own system of views and values, self-awareness
• Hobbies: modern youth alternative trends in fashion, art, music, cinematography, technology

The leading activity

Intimate-personal, emotional communication with Svershniki

How to develop

allow the child to communicate with Sversniki, to secure holidays, joint trips, to learn in performances, post-posts. Spend time in hobby groups.

SENIOR SCHOOL (14 to 17 years old)

• Life planning
• Acceptance of one's own appearance, awareness of the features of one's body, creation of an image of oneself
• Assimilation of the male or female role
• Expanding range of social roles and interests
• Looking to the future, building life plans and prospects
• Self-control, self-regulation
• Desire for discussion
• Hobbies: professional and moral definition in the outside world

Leading activity

Educational and professional in the process of which worldview, professional interests, ideals are formed.

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