Child Development Stages
Child Developmental Stages Child development comes in stages, and although not all children develop at the same rate, this timeline describes what typically occurs from the pre-natal stage through infancy and up to two years old. Pre-natal development is the most significant segment of human development. 15 days after conception the embryonic stage begins and continues until about the 8th week, or until the embryo is around an inch in length. The cells of the embryo are multiplying and taking on different functions.
This critical period, the first trimester, the growing embryo is most susceptible to damage from external sources including viral infections, x-rays and other radiation, and poor nutrition. By the third week, the heart is forming and the brain and spinal cord is beginning to develop as well as the beginning of the gastrointestinal tract. During weeks four and five, the vertebra, the lower jaw, the larynx, and the ear and eye begin to develop. The heart, which is still outside the body, now beats with a regular rhythm.
Arm and leg “buds” are visible with hand and foot “pads,” but the embryo still has a tail and looks similar to a pig, rabbit, elephant, or chick embryo. By the time the embryo is six weeks it is approximately 1/2 inch long and weighs around 1/1000 of an ounce. The nose, jaw, palate, and lung buds are forming. The fingers and toes have formed, but may still be webbed. The tail is receding, and the heart is almost fully developed. By weeks seven and eight the embryo is growing to an inch in length and weighing up to 1/15 of an ounce (a little bigger than an aspirin).
The eyes have moved forward on the face, and the eyelids and tongue begin to form. All essential organs have begun to form. The embryo now resembles a human being, with facial features and the external ears appear. Also, the beginnings of external genitalia are beginning. The circulation through the umbilical cord is well developed, and the long bones begin to form. At this point the embryo has developed enough to call it a fetus. All of the organs and structures found in a full-term newborn are present. By weeks nine through 12, the fetus is around three inches, weighing 1 ounce.
The head is about half of the fetus’ size and the face is well formed. The eyelids close now and will not reopen until about the 28th week. The tooth buds for the baby teeth appear. The genitalia are now clearly male or female. Weeks 13 to 16 mark the beginning of the second trimester. The fetus is around six inches long. The skin of the fetus is almost transparent, and fine hair (called lanugo) develops on the head. The fetus becomes active and has movements, including sucking. The heart beats120-150 beats per minute and brain waves are detectable. Eyebrows and lashes appear and nails appear on fingers and toes by weeks 17-20.
The fetus is typically six inches long by now. The mother can feel the fetus moving at this stage and the fetal heartbeat can be heard with a stethoscope. In the next month the fetus will grow to 11 inches and weigh slightly over 1 lb. All the eye components have developed, and footprints and fingerprints are forming. The fetus now has a startle reflex. Weeks 25-28 begin the third trimester. The fetus grows up to 15 inches, and almost 3 lbs. The brain rapidly develops at this time. The nervous system is developed enough to control some body functions, and the eyelids open and close.
A baby born at this time may survive, but the chances of complications and death are high. Weeks 29 to 32 see further development towards independent life. There is a rapid increase in the amount of body fat and the fetus begins storing its own iron, calcium, and phosphorus. The bones are fully developed, but still soft and pliable. There are rhythmic breathing movements present, the fetal body temperature is partially self-controlled, and there is increased central nervous system control over body functions. By weeks 33-36 the fetus has grown to 16 to 19 inches, and up to 5 or 6 lbs. The lanugo (body hair) begins to disappear.
A baby born at 36 weeks has a high chance of survival. At 38 weeks, the fetus is considered full term. It fills the entire uterus, and its head is the same size around as its shoulders. The mother supplies the fetus with the antibodies it needs to protect it against disease. From birth to one-month, the infant may appear red and a bit swollen, which will quickly subside as the facial features realign. The infant may keep her/his hands clenched and arms and legs curled in. This is a familiar, comforting position to the baby who has never known anything but closeness. The infant’s muscles will relax during the next few weeks.
The first few days are guided primarily by instinct. Already at birth the baby will recognize their mother’s voice and turn their head toward that single voice even with other people in the room. Soon the baby will identify other familiar voices that they have heard from the womb. A one-month-old baby is usually capable of making gurgling noises and can lift their head a little while lying on their stomach. They can focus on an object for a short time. Babies at this stage do not like blankets or objects to cover their face. As two months passes, babies start to hold their heads up.
Their heads will bobble around because their heads are heavy and they don’t have strength in their neck to hold their head high. A two-month-old baby may start rolling from side to side and respond to a person by looking at them. Their gurgling sounds have not progressed much yet. By three months most babies can lift their head and chest while lying on their stomach. They can smile when you talk to them and move their arms and legs a lot. A three-month-old baby may recognize a bottle or their mom at feeding time. By four months old a baby will hold up their head without bobbing because their neck muscles are developing.
They can laugh out loud and like to play, especially peek-a-boo. Babies at four months roll from front to back so parents have to be very careful about where they lie their baby down; not on a chair or couch because babies can roll off and fall on the ground. Babies at this age start trying to grab objects, like a rattle or toy. Somewhere in this timeline a baby will start to hold its own bottle, if bottle-feeding is used. By the time a baby reaches six months old they can usually sit up with a little support. They start to respond to voices by smiling and looking toward the sound.
They now put the objects they grab at in either hand and from their hands to their mouths. Parents have to be very careful because babies put everything in their mouths and can choke on them. Between six and nine months babies develop a lot. They can now sit alone and change their position. Most babies start to crawl by nine months. Parents really need to watch out once their baby becomes mobile. A nine-month-old baby starts to say words, like “mama” and “dada” and can respond when someone says their name. Nine-month-old babies recognize people they know, especially their mom, dad, or primary caregiver.
A twelve-month-old baby can usually speak two or three words. They can pull themselves up to stand and maybe take a few steps while holding on to something like a table or chair. Babies at this stage can nod their head to say yes and pick up things by using their thumb and finger. If parents are inclined to use a sipper cup, babies will start being able to hold their own cup. A one year old can show love by looking, hugging and usually kissing, although a very sloppy kiss. Twelve months old babies are now moving into toddler-hood. Basic standards, such as teaching, CPR, clothing, first aid, etc. ow consider this baby to be a toddler by their height, size and weight. Most babies walk by the time they reach fifteen months. Some babies can feed themselves but parents beware, this will not be pretty. Babies start to use their voice and make their voice go up and down at this stage. They can usually say five or more words. Fifteen-month-old toddlers can drink from a cup quite well at this age. At eighteen months, most toddlers can walk and run a little bit. They start being able to climb stairs and parents need to gate any stairs in their house. Toddlers at this age can play with pull toys with wheels and scribble on paper with crayons.
Toddlers have greater verbal skills by now and are building their vocabulary with ten to twenty words. Parents can start to give their toddler directions and expect the child to understand at this stage. A two-year-old, or toddler, has developed quite a bit in the past six months. They are able to kick a large ball and run to chase it. Two-year-olds start to recognize a picture and know if it is upside down. They like to look in books and turn the pages, and can give you a specific toy when asked. A toddler at two starts to put words together, but not really complete a sentence, usually asking for something like “more juice. ”
