When born, what size is a babys head in relation to the rest of his/her body?

At birth, a baby’s head is relatively large and strong a quarter to a third of the total length of the body, while the head of an adult is only one eighth.

How big is a baby’s head in relation to its body?

Generally, a newborn’s head measures about half the length of the baby’s body in inches plus 10 cm. So an 18-inch-long child would be 45.7 centimeters (18 x 2.54). His head would measure about 32.9 cm, or just under 13 inches.

What is the circumference of the head of a newborn?

The average head circumference at birth is approximately 13.5 inches (34.5 cm).

How tall is the head of an adult child?

The head of a newborn is on average 35 cm. In general, a newborn’s head measures about half the length of the baby’s body in inches plus 10 cm. So an 18-inch-long child would measure 18 x 2.54 (45.7 centimeters). His head would measure about 32.9 cm, or just under 13 inches.

Is your head full size at birth?

A newborn’s head weighs about a quarter of its body weight! Babies are born with many more neurons than in the adult brain, but the brain itself weighs about a third more. It is disproportionately large in relation to the size of the body.

Is the head circumference at birth 32 cm?

The normal head circumference in term newborns is 32 to 38 cm. Microcephaly is defined as a head circumference that is 2 standard deviations (SD) below the mean for age and sex, or approximately below the 2nd percentile.

Do babies grow big heads?

Macrocephaly is the name for an unusually large head. A child with macrocephaly has a larger head than most other babies of the same age and sex. In many cases, this condition is benign or harmless. In other cases, it may indicate an underlying medical condition, such as a genetic syndrome or a brain tumor.

What does the size of the baby’s head say?

Another measure of a baby’s growth is the head circumference or the size of the baby’s head. It is important because it can indicate how well your brain is growing. If your baby’s brain isn’t growing properly, he may have a condition known as microcephaly.

What is the normal size of the head?

According to Wikipedia, the average head circumference of an adult is 55 cm (21 3⁄4 inches) for women and 57 cm (22 1⁄2 inches) for men. Another study in the UK shows a slightly different result: the average head size for women is 55.2 cm and the average head size for men is 57.2 cm.

What is the normal increase in head circumference?

The average increase in total head circumference from birth to the third month is 5 cm (1.97 inches) and 4 cm (1.57 inches) averaged over 3 to 6 months. This trend slows even more in the first year; between 6 and 9 months, the head circumference increases 2 cm (0.79 in.)

Is 17 inches small for a newborn?

The normal length of a newborn ranges from 18 inches to 22 inches, with an average of 20 inches. Being shorter or longer than the average length does not necessarily indicate a problem. In fact, the size of the baby’s parents can influence the length of the baby’s birth.

How tall is a newborn?

The medical term for a large baby is macrosomia, which literally means “large body.” Some researchers believe that a baby is large if it weighs 4,000 grams or more at birth, and others say that a baby is large if it weighs 4,500 grams or more (Rouse et al. 1996).

What is considered a large head circumference at birth?

The simple definition of the word macrocephaly is “big head.” Doctors use this diagnosis when a child’s head size is in the 98th percentile. This means that the baby’s head is larger than 98% of other babies of the same age. Sometimes doctors detect macrocephaly during an ultrasound before the baby is born.

What part of the body never grows from birth?

Qualifications: Study of human biology (now I am a taxi driver). Answer: The eyeball is the only organism that does not grow from birth. It is fully developed when you are born.

How big is the brain at birth?

Average brain size was 20 cubic inches (341 cubic centimeters) at birth and 34 cubic inches (558 cubic centimeters) at 90 days. In other words, the newborn’s brain has grown from about 33% of the average adult brain size to 55% in three months.

Are babies’ eyes big at birth?

Babies are born with eyes that are about 16.5 millimeters long. At 20 or 21 years the eyes do not grow when they reach about 24 millimeters. The weight of the lenses will continue to increase over time. Scientists say that the eyes grow rapidly after birth.

Microcephaly is a birth defect where a baby’s head is smaller than expected when compared to babies of the same sex and age. Babies with microcephaly often have smaller brains that might not have developed properly.

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What is microcephaly?

Microcephaly is a condition where a baby’s head is much smaller than expected. During pregnancy, a baby’s head grows because the baby’s brain grows. Microcephaly can occur because a baby’s brain has not developed properly during pregnancy or has stopped growing after birth, which results in a smaller head size. Microcephaly can be an isolated condition, meaning that it can occur with no other major birth defects, or it can occur in combination with other major birth defects.

What is severe microcephaly?

Severe microcephaly is a more serious, extreme form of this condition where a baby’s head is much smaller than expected. Severe microcephaly can result because a baby’s brain has not developed properly during pregnancy, or the brain started to develop correctly and then was damaged at some point during pregnancy.

Other Problems

Babies with microcephaly can have a range of other problems, depending on how severe their microcephaly is. Microcephaly has been linked with the following problems:

• Seizures
• Developmental delay, such as problems with speech or other developmental milestones (like sitting, standing, and walking)
• Intellectual disability (decreased ability to learn and function in daily life)
• Problems with movement and balance
• Feeding problems, such as difficulty swallowing
• Hearing loss
• Vision problems

These problems can range from mild to severe and are often lifelong. Because the baby’s brain is small and underdeveloped, babies with severe microcephaly can have more of these problems, or have more difficulty with them, than babies with milder microcephaly. Severe microcephaly also can be life-threatening. Because it is difficult to predict at birth what problems a baby will have from microcephaly, babies with microcephaly often need close follow-up through regular check-ups with a healthcare provider to monitor their growth and development.

How Many Babies are Born with Microcephaly?

Microcephaly is not a common condition. Researchers estimate that about 1 in every 800-5,000 babies is born with microcephaly in the United States.

Causes and Risk Factors

The causes of microcephaly in most babies are unknown. Some babies have microcephaly because of changes in their genes. Other causes of microcephaly, including severe microcephaly, can include the following exposures during pregnancy:

• Certain infections during pregnancy, such as rubella, toxoplasmosis, or cytomegalovirus
• Severe malnutrition, meaning a lack of nutrients or not getting enough food
• Exposure to harmful substances, such as alcohol, certain drugs, or toxic chemicals
• Interruption of the blood supply to the baby’s brain during development

Some babies with microcephaly have been reported among mothers who were infected with Zika virus while pregnant. CDC scientists announced that enough evidence has accumulated to conclude that Zika virus infection during pregnancy is a cause of microcephaly and other severe fetal brain defects.

CDC continues to study birth defects, such as microcephaly, and how to prevent them. If you are pregnant or thinking about becoming pregnant, talk with your doctor about ways to increase your chances of having a healthy baby.

Diagnosis

Microcephaly can be diagnosed during pregnancy or after the baby is born.

During Pregnancy

During pregnancy, microcephaly can sometimes be diagnosed with an ultrasound test (which creates pictures of the body). To see microcephaly during pregnancy, the ultrasound test should be done late in the 2nd trimester or early in the third trimester. For more information about screening and confirmatory tests during pregnancy, visit CDC’s birth defects diagnosis web page.

After the Baby is Born

To diagnose microcephaly after birth, a healthcare provider will measure the distance around a newborn baby’s head, also called the head circumference, during a physical exam. The provider then compares this measurement to population standards by sex and age. Microcephaly is defined as a head circumference measurement that is smaller than a certain value for babies of the same age and sex. This measurement value for microcephaly is usually more than 2 standard deviations (SDs) below the average. The measurement value also may be designated as less than the 3rd percentile. This means the baby’s head is extremely small compared to babies of the same age and sex.

Head circumference growth charts for newborns, infants, and children up to age 20 years in the United States can be found on CDC’s growth charts website. Head circumference growth charts based on gestational age at birth (in other words, how far along the pregnancy was at the time of delivery) are also available from INTERGROWTH 21stexternal icon. CDC recommends that health care providers use the WHO growth charts to monitor growth for infants and children ages 0 to 2 years of age in the United States.

Microcephaly can be determined by measuring head circumference (HC) after birth. Although head circumference measurements may be influenced by molding and other factors related to delivery, the measurements should be taken on the first day of life because commonly-used birth head circumference reference charts by age and sex are based on measurements taken before 24 hours of age. The most important factor is that the head circumference is carefully measured and documented. If measurement within the first 24 hours of life is not done, the head circumference should be measured as soon as possible after birth. If the healthcare provider suspects the baby has microcephaly, he or she can request one or more tests to help confirm the diagnosis. For example, special tests like like magnetic resonance imaging can provide critical information on the structure of the baby’s brain that can help determine if the newborn baby had an infection during pregnancy. They also can help the healthcare provider look for other problems that might be present.

Treatments

Microcephaly is a lifelong condition. There is no known cure or standard treatment for microcephaly. Because microcephaly can range from mild to severe, treatment options can range as well. Babies with mild microcephaly often don’t experience any other problems besides small head size. These babies will need routine check-ups to monitor their growth and development.

For more severe microcephaly, babies will need care and treatment focused on managing their other health problems (mentioned above). Developmental services early in life will often help babies with microcephaly to improve and maximize their physical and intellectual abilities. These services, known as early interventionexternal icon, can include speech, occupational, and physical therapies. Sometimes medications also are needed to treat seizures or other symptoms.

Other Resources

The views of these organizations are their own and do not reflect the official position of CDC.

Mother To Babyexternal icon (on behalf of the Organization of Teratology Information Specialists)
This website provides comprehensive information to mothers, healthcare professionals, and the general public about exposures during pregnancy.

References

1. National Birth Defects Prevention Network. Major birth defects data from population-based birth defects surveillance programs in the United States, 2006-2010. Birth Defects Research (Part A): Clinical and Molecular Teratology. 2013;97:S1-S172.