Head Circumference Reference Data: Birth to 18 Years

(1)

Head

Circumference

Reference

Data:

Birth to

18 Years

Alex F. Roche,

MD, PhD, DSc, Debabrata

Mukherjee,

PhD,

Shumei

Guo, PhD, and William

M. Moore,

MD, MPH

From Wright State University School of Medicine, Yellow Springs, and Ross Laboratories,

Columbus, Ohio

ABSTRACT. Highly reliable data from a sample of 888 white US children, measured serially in a single study,

have been used to provide reference data for head

circum-ference from birth to 18 years of age. The present data

differ little from those already available for the age range

from birth to 36 months of age, but they are considerably

higher (about 0.5 cm) at older ages for boys and tend to

be slightly higher for girls. These new reference data are smoother across age than those used currently for

screen-ing and evaluation. Percentiles for 6-month increments from birth to 6 years have been provided. Pediatrics 1987;79:706-712; head circumference.

The measurement of head circumference is an

important part of the clinical examination of any

infant. The method of measurement is highly

standardized’ and sets of reference data are

avail-able with which observed values can be compared.

The widely used National Center for Health

Statis-tics (NCHS) percentiles for infants were derived

from participants in the Fels Longitudinal Study.2’3

The reference data complied by Nellhaus4 for ages

from birth to 18 years are composites of 14 studies, published between 1952 and 1965, in which children

from families of low socioeconomic status were

ovenrepresented and different ethnic groups were

included.

During infancy, the measunement and

interpne-tation of head circumference has an important

place in screening for conditions in which head size is abnormal, eg, hydrocephalus and microcephaly.

This measurement is less important during

child-hood and adolescence, but it is relevant to the

Received for publication Jan 23, 1986; accepted June 20, 1986.

Reprint requests to (A.F.R.) Division of Human Biology,

De-partment of Pediatrics, Wright State University School of

Mad-icine, 1005 Xenia Aye, Yellow Springs, OH 45387-1695.

American Academy of Pediatrics.

extended observation of children whose head

cm-cumferences were unusual during infancy. After

infancy, reference data can assist judgments of the

normality of recorded measurements and assist the

recognition of intrafamilial clustering of unusual values.

The aim of the present study was to provide

reference data for head circumference from birth to

18 years and 6-month increments from birth to 6

years using data from a single study in which all

measurements were made using the same method

and the observer differences were known to be

small.

SUBJECTS AND METHODS

The mixed longitudinal data that have been

ana-lyzed were recorded from 888 participants in the

Fels Longitudinal Study between 1930 and 1982.

Secular trends in these data are small and

incon-sistent. Many of these data were used earlier to

construct the NCHS growth charts for the age

range from birth to 36 months.2’3 Also, the present sample of Fels’ participants is similar to a sample

from which 6-month increments in head

circumfen-ence from birth to 36 months have been derived.5

The participants in the Fels Longitudinal Study

were from families with a wide range of

socioeco-nomic status living in southwestern Ohio. These

participants were the products of normal

pregnan-cies and were in good health. There are 13 black

children in the Fels Longitudinal Study; the

ne-mainder are white. The data from the black

partic-ipants were excluded from the present analyses.

Data from four sets of participant triplets have

been omitted from the present analyses because

triplets were ovenrepresented and because they were

omitted also from the analyses made previously to

construct sets of reference data.2’3’5 Data from the

(2)

have been used in the present and were used in the

past analyses; the data from these twins did not

differ significantly from those for the remainder of

the group. There are some like-sex first-degree

nel-atives, eg, sister-sister, in the data set. Random

selection of one member from each such pair or

triad did not alter the descriptive statistics to a

statistically significant extent, but the sample sizes

were reduced by about 20%. Consequently,

exclu-sions were not made on the basis of familial nela-tionships.

Head circumference was measured serially at

birth, 1, 3, 6, 9, and 12 months and then each 6

months to 18 years. A nonstretchable tape

gradu-ated in millimeters was used. In 1976, the tape

measure used previously was replaced by an

inser-tion tape (INSER-TAPE, Ross Laboratories), after

it had been shown that the differences between

pairs of measurements with the two types of tape

did differ significantly. Use of an insertion tape

reduces the probability of measurement errors.6 The method of measurement was the same with

each type of tape. The tape was placed with its

inferior margin just touching the superior bonders

of the eyebrows. If superciliary arches were present,

the tape was placed superior to them. The posterior

part of the tape was aligned so that the maximum

head circumference was recorded, even if the

meas-urement included the external occipital

protuber-ence. Care was taken to ensure that the plane of

the tape was the same on the left and night sides of the head. Hair pins and clips were removed and

lange amounts of hair, eg, braids, were excluded

from the plane of measurement.

The tape was pulled tightly around the head, and

the circumference was recorded to the nearest

mil-limeten by two observers measuring independently. If the difference between a pain of measurements

was less than 2 mm, the mean of the pair was used in the analyses. If their measurements differed by

more than 2 mm, each observer repeated the

meas-urement. The mean of the second pair of

measure-ments was used in the analyses if the separate

measurements differed by less than 2 mm. On the

rare occasions when the difference within each pair

of measurements exceeded 2 mm, the mean of all

four measurements was used. Analyses of

intenob-server differences (n = 1386 pairs of data) showed

technical errors

(J

(d/2n) of 0.9 mm and

coeffi-cients of variation of 0.0002 that were independent of age.

The head circumference data were grouped by

sex at ages corresponding to those of the scheduled

examinations. Selected percentiles (fifth, tenth,

twenty-fifth,, fiftieth, seventy-fifth, ninetieth, and

ninety-fifth) were calculated.7 Subsequently, the

calculated percentiles and the means and standard deviations were smoothed across age using a family

of mathematical functions fitted by a nonlinear

iterative procedure. These functions gave satisfac-tory results in terms of minimal differences between the observed and estimated values. The mathemat-ical functions were applied to the calculated values for the selected percentiles, the means, and the ±2

and ±3 SD levels at each of the scheduled ages,

although the estimated values are reported only at

annual intervals for ages olden than 6 years.

Six-month increments in head circumference

from birth to 6 years were calculated. Selected

percentiles, means, and standard deviations were

obtained and subsequently smoothed using a family

of mathematical functions.

RESULTS

Selected distribution statistics for smoothed val-ues from birth to 18 years are presented in Tables

1 and 2 for boys and girls, respectively. The

per-centile levels tended to be higher for boys than

girls; differences between the distributions for the two sexes were significant (P

<

.05) at each age by

the Kolmogonov-Smirnov test. The percentile curves are shown in Figs 1 and 2 for the age range

birth to 18 years. Between birth and 6 months of

age, the separate percentile curves are close in these

figures. Consequently, percentile curves from birth to 6 years are presented using a larger age scale in Figs 3 and 4.

The means were significantly larger (P

<

.05) for boys than for girls at each age except 13 years. The significance of the differences between

correspond-ing means was established using t tests, after

ad-justing for the Bonferroni inequality by o’/p where

p = number of tests performed, to maintain the

overall type I error.

The smoothed means ±2 SD and ±3 SD from the

present data are shown in Figs 5 and 6 where

comparisons are made with the data of Nellhaus,4

who made available his unpublished means and

standard deviations. The differences between the

present data and the corresponding values of

Nell-haus (mean

±

2 SD) were small from birth to 12

months for boys and from birth to about 18 months for girls. At older ages, the present values for boys

were about 0.5 to 1.5 cm greater than the

come-sponding Nellhaus values. For example, an

11-year-old boy with a head circumference at the -2 SD

level on the Nellhaus chart is at -2.5 SD level with

the present data, and a boy of this age who is +2 SD with the Nellhaus chart is +1.5 SD with the

present data. For the girls, there was only a slight

tendency for the present values to exceed those of

(3)

TABLE 1. Distribution Statistics for Smoothed Head Circumference Values (cm) of Boys

Age

(yr)

n Percentiles Mean SD

5th 101h 25th 50th 75th 90th 95th

Birth 177 32.88 33.22 34.21 35.25 36.23 37.12 37.80 34.61 1.62

0.08 277 34.70 35.06 36.00 37.01 37.98 38.84 39.63 37.30 1.47

0.25 291 37.79 38.17 39.03 40.00 40.96 41.76 42.69 40.28 1.42

0.50 303 41.09 41.49 42.29 43.22 44.16 44.92 45.93 43.52 1.34

0.75 292 43.35 43.77 44.52 45.43 46.36 47.10 48.11 45.54 1.32

1.00 307 44.91 45.33 46.06 46.97 47.89 48.62 49.60 46.87 1.32

1.50 297 46.75 47.18 47.90 48.81 49.72 50.45 51.32 48.20 1.35

2.00 299 47.69 48.12 48.84 49.77 50.68 51.41 52.20 49.20 1.36

2.50 226 48.21 48.65 49.38 50.31 51.23 51.97 52.70 50.02 1.36

3.00 184 48.55 48.99 49.73 50.67 51.59 52.34 53.03 50.52 1.37

3.50 181 48.81 49.24 49.99 50.94 51.87 52.62 53.29 50.99 1.39

4.00 178 49.02 49.45 50.22 51.16 52.10 52.87 53.52 51.23 1.40

4.50 174 49.22 49.65 50.42 51.37 52.32 53.09 53.74 51.51 1.44

5.00 170 49.40 49.83 50.62 51.57 52.54 53.30 53.95 51.78 1.46

5.50 127 49.59 50.02 50.81 51.77 52.74 53.51 54.15 52.06 1.49

6.00 176 49.77 50.20 51.01 51.96 52.95 53.72 54.36 52.22 1.45

7.00 182 50.13 50.56 51.39 52.35 53.36 54.14 54.76 52.52 1.39

8.00 174 50.50 50.92 51.77 52.73 53.77 54.55 55.17 52.86 1.39

9.00 160 50.86 51.27 52.15 53.12 54.17 54.96 55.58 53.19 1.43

10.00 157 51.22 51.63 52.53 53.50 54.58 55.38 55.99 53.57 1.50

11.00 152 51.58 51.99 52.92 53.89 54.99 55.79 56.39 53.93 1.54

12.00 150 51.94 52.35 53.30 54.27 55.40 56.20 56.80 54.11 1.45

13.00 132 52.31 52.71 53.68 54.66 55.81 56.62 57.21 54.43 1.56

14.00 127 52.67 53.07 54.06 55.04 56.22 57.03 57.62 54.99 1.60

15.00 124 53.03 53.43 54.44 55.43 56.63 57.44 58.02 55.48 1.58

16.00 113 53.39 53.78 54.82 55.81 57.03 57.86 58.43 55.97 1.59

17.00 113 53.76 54.14 55.20 56.20 57.44 58.27 58.84 56.38 1.56

18.00 108 54.12 54.50 55.59 56.59 57.85 58.68 59.25 56.74 1.77

smoother across age than those of Nellhaus.4 In to be highly reliable. Nevertheless, there were only

Figs 5 and 6, ±3 SD levels for the present data are small differences between the present data and the

shown so that more extreme head circumferences composite data of Nellhaus,4 at ages younger than

can be evaluated readily. 12 months for boys and 18 months for girls. At

Selected smoothed percentiles for 6-month incne- older ages, the Nellhaus data are about 0.5 to 1.5

ments in head circumference are presented in Table cm less than corresponding present values for boys,

3 and in Figs 7 and 8 for boys and girls, respectively. but the differences are considerably less for girls.

These percentiles were smoothed using mathemat- This could reflect the low socioeconomic status of

ical functions and are presented with each incre- many subjects in the composite Nelihaus data, sec-ment opposite the end of the corresponding 6- ulan changes,9 or differences in the method of

mea-month interval. There was a rapid decrease in rate suning head circumference.

during the first year; later the decrease was slow The present data differ only slightly from the

but continued until at least 6 years. The patterns NCHS reference data for birth to 36 months.2’3 of change were similar for the two sexes, but the This was expected because these sets of percentile

early deceleration tended to be greater for the boys values were obtained from overlapping samples.

than the girls. The median increments for the boys Replacement of the NCHS data by the present data tended to be greater than those for the girls up to would not be justified. Because the NCHS percent-the age of 4.5 years, after which there was a tend- iles extend only from birth to 36 months, they have ency to an opposite sex difference. limited applicability in intervention programs that

extend to olden ages. Reference data for a larger age

DISCUSSION range allow the follow-up of children with abnormal

values during infancy and recognition of the

catch-Early in infancy there are rapid increases in head up growth in head circumference that can occur up

circumference and marked histologic changes in the to about 5 years, when the cranial sutures inter-brain.8 Therefore, early recognition of deviations lock.’0” The present data will allow interpretation from normal growth is important. The present nef- of head circumference values for parents, using

18-enence data were obtained in a single study using a year values as reference data, and for children older

(4)

4’

44

42

3,

56

54

36

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Fig 2. Selected percentilesfor smoothed head circum-ference values of girls from birth to 18 years.

of intrafamilial clustering of unusual values.’2 ments from birth to 6 months are larger by about

Reference data for 6-month increments are al- 0.7 cm at the median level. This may reflect

differ-ready available fon the age range birth to 3 years.5”3 ences in the sample used, which included data

ex-The present study has extended the mange of avail- tending to 1982 instead of 1978 but excluded blacks,

able reference data for 6-month increments to 6 rather than differences in measurement technique.

years. The larger age range will be useful in the The present tables and figures can be used to

evaluation of changes observed in intervention pro- evaluate the normality of head circumference from

grams. The distributions of the present increments birth to 18 years. There is a pubescent spurt in

from birth to 36 months are similar to those pub- head circumference which has been reported to be

lished previously,5”3 except for the increments from larger in girls than in boys,’4 unlike the spurts in

birth to 6 months. In the present data, the incre- stature and in weight. The spurt in head

cincumfer-TABLE 2.

Distribution Statistics for Smoothed Head Circumference Values (cm) of Girls

Age

(yr)

5th 101h 25th 50th 75th 90th 95th

Birth 165 32.27 33.01 33.79 34.64 35.38 36.11 36.81 33.88 1.42

0.08 247 33.76 34.49 35.31 36.13 36.89 37.59 38.18 36.42 1.13

0.25 247 36.47 37.18 38.04 38.80 39.61 40.28 40.71 39.10 1.65

0.50 285 39.53 40.19 41.06 41.79 42.63 43.29 43.63 42.20 1.22

0.75 272 41.75 42.36 43.21 43.94 44.79 45.48 45.81 44.18 1.28

1.00 270 43.38 43.94 44.75 45.50 46.35 47.07 47.45 45.46 1.33

1.50 264 45.47 45.95 46.68 47.47 48.30 49.09 49.62 46.92 1.25

2.00 261 46.63 47.05 47.73 48.56 49.37 50.23 50.89 48.02 1.40

2.50 210 47.31 47.70 48.34 49.21 50.01 50.91 51.67 48.71 1.31

3.00 159 47.74 48.11 48.74 49.63 50.42 51.35 52.17 49.40 1.25

3.50 151 48.03 48.41 49.02 49.93 50.73 51.67 52.53 49.78 1.29

4.00 161 48.26 48.64 49.25 50.17 50.98 51.93 52.80 50.11 1.27

4.50 146 48.46 48.83 49.46 50.39 51.20 52.16 53.03 50.40 1.29

5.00 153 48.63 49.02 49.65 50.59 51.42 52.37 53.23 50.68 1.33

5.50 120 48.80 49.19 49.84 50.78 51.62 52.57 53.43 50.99 1.36

6.00 155 48.96 49.36 50.02 50.97 51.82 52.77 53.61 51.16 1.34

7.00 168 49.27 49.69 50.38 51.35 52.22 53.17 53.96 51.58 1.42

8.00 163 49.58 50.03 50.74 51.72 52.62 53.56 54.32 52.00 1.41

9.00 156 49.89 50.36 51.09 52.09 53.01 53.95 54.67 52.27 1.38

10.00 166 50.20 50.69 51.45 52.46 53.41 54.34 55.01 52.65 1.41

11.00 150 50.51 51.02 51.81 52.83 53.81 54.73 55.36 53.05 1.47

12.00 162 50.82 51.35 52.17 53.20 54.20 55.12 55.71 53.50 1.50

13.00 140 51.13 51.68 52.52 53.57 54.60 55.52 56.06 53.96 1.49

14.00 140 51.44 52.01 52.88 53.94 54.99 55.91 56.41 54.21 1.43

15.00 133 51.75 52.34 53.24 54.31 55.39 56.30 56.76 54.31 1.44

16.00 132 52.06 52.67 53.60 54.68 55.79 56.69 57.11 54.45 1.48

17.00 139 52.37 53.00 53.95 55.05 56.18 57.08 57.46 54.57 1.39

18.00 110 52.68 53.33 54.31 55.42 56.58 57.47 57.80 54.55 1.33

60 .

_

AGE (Y#{149}a)

0 2 3 4 5 6 7 8 9 10 1112131415161718

58 58

56 56

54 54

52 50

44

42

iiL.

32r

-

::

-:- 2 3 5 6 7 8

3,

AGE(Yeas)

Fig 1. Selected percentiles for smoothed head

circum-ference values of boys from birth to 18 years.

AGE Yas)

0 2 3 4 5 6 7 8 9 10 1 12131415161718

. . .60

(5)

3

AGE Yea’s)

0 3

AGE )Yea,s)

t- . -t-T --#{149}-#{149}

---.--.

-.

.

iijIi

±

-.

I

. 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

0 1

AGE (Yea’s) 00 05

GIRLS

0 15 20 25 30 35 40 a5 50 55 60

_____

00 05 10 15 20 2.5 30 35 40 45 50 55 60

0 1 2 3 4 5 I 8 9 10 11 1( 13 1 I 15 16 17 18

AGE (Yeals)

#{182}520 25 30 35 40 45 50 55 60

Fig 3. Selected percentiles for smoothed head

circum-ference values of boys from birth to 6 years.

AGE (Yeas)

-‘ S 38 36 34 32

Fig 6. Smoothed means (±2 SD and ±3 SD) from head circumference data for girls. Present data (-)

com-pared with data from Nellhaus4 (-

-40 38

---

3#{128} 34

----

32

36

AGE(Yea’s)

Fig 4. Selected percentiles for smoothed head

circum-ference values of girls from birth to 6 years.

AGE (Ya,s)

AGE (Yeaes)

Fig 5. Smoothed means (±2 SD and ±3 SD) from head

circumference data for boys. Present data (-)

com-pared with data from Nellhaus4 (-

-ence is associated more with changes in scalp

thick-ness than in cranial thickness.’5”6 Because

pubes-cent spurts in head circumference are small and

36 occur at different ages among individuals, they are

54 not apparent in the present reference data.

There-:

fore, serial data for individuals can be plotted at all

48 5 ages in relation to the present reference data

with-46 out problems of interpretation resulting from

mdi-vidual differences in the timing of pubescence. The finding that head circumferences were significantly

larger in boys than in girls is in agreement with

earlier reports.’7”8

The present percentile values were derived from

a sample of white US children, but they should be

applicable to US black children also.’9 However, it

should not be assumed that they are appropriate

for other ethnic groups, because large differences

in head circumference have been reported between

ethnic groups.20’2’ Various socioeconomic levels

were represented in the Fels sample and some low

birth weight infants were included (4.6%

<

2.5 kg

birth weight). Adjustments were not made for

so-cioeconomic status because of the vague and

sub-jective nature ofthis categorization. The prevalence

of low birth weight infants was similar to that

expected in a random sample; the numbers were

too few to allow the development of separate

ref-erence data for this group.

Head circumference is an important measure

be-cause it is highly correlated with brain weight,

especially during infancy.22’23 Many infants with

values more than 3 SD below the mean from the

time of birth, as may occur in those with fetal

alcohol syndrome, on with values that decrease from

the normal range to be 2 SD on more below the

mean are mentally retarded.24’25 Lange values,

es-pecially those that increase in percentile level on

are associated with large increments, suggest the

need for tests to exclude hydrocephalus. Less

com-mon causes of large values for head circumference

(6)

associ-10

3

B

AGE(Yea,s)AT ENDOF INTERVAL

0

6

5

4

REFERENCES

1. Roche AF: Growth assessment in abnormal children. Kidney

mt

1978;14:369-377

2. Hamill PVV, Drizd TA, Johnson CL, et al: NCHS growth

curves for children birth-18 years, United States, Vital and

Health Statistics, series 11, No. 165, Department of Health,

TABLE 3.

Distribution Statistics for Smoothed Head Circumference 6-Month

Incre-ments (cm)

End of

Interval

5th 101h 25th 50th 75th 90th 95th

Boys 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 Girls 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 163 282 285 287 223 181 176 174 171 168 125 165 149 251 254 253 206 153 148 156 143 147 120 150 7.37 2.08 0.55 0.11 -0.03 -0.07 -0.09 -0.10 -0.11 -0.12 -0.13 -0.13 6.90 2.07 0.60 0.14 -0.01 -0.08 -0.12 -0.14 -0.16 -0.18 -0.19 -0.20 7.87 2.38 0.85 0.37 0.19 0.11 0.06 0.04 0.02 0.01 0.01 0.00 7.27 2.43 0.89 0.36 0.16 0.08 0.04 0.02 0.01 0.01 0.00 0.00 8.40 2.82 1.21 0.68 0.45 0.32 0.24 0.18 0.13 0.10 0.08 0.06 8.18 2.79 1.30 0.77 0.52 0.36 0.26 0.19 0.13 0.10 0.07 0.05 9.49 3.33 1.55 0.95 0.69 0.53 0.43 0.34 0.28 0.23 0.18 0.15 8.70 3.28 1.64 1.06 0.78 0.61 0.48 0.39 0.31 0.25 0.20 0.16 10.22 3.89 1.92 1.23 0.93 0.75 0.63 0.53 0.45 0.38 0.32 0.27 9.37 3.66 1.93 1.32 1.02 0.83 0.69 0.57 0.48 0.40 0.33 0.28 10.96 4.48 2.33 1.54 1.19 0.98 0.83 0.71 0.61 0.53 0.46 0.39 9.91 4.18 2.34 1.65 1.31 1.09 0.92 0.79 0.67 0.58 0.49 0.42 11.31 5.03 2.70 1.78 1.37 1.14 0.99 0.88 0.78 0.70 0.62 0.55 10.37 4.63 2.81 2.07 1.66 1.38 1.16 0.97 0.82 0.65 0.58 0.49 9.43 3.41 1.52 1.01 0.71 0.50 0.44 0.35 0.29 0.30 0.24 0.18 8.55 3.22 1.71 1.08 0.80 0.57 0.40 0.37 0.27 0.29 0.25 0.24 1.46 0.93 0.85 0.55 0.43 0.37 0.35 0.38 0.24 0.54 0.28 0.25 2.31 0.85 0.78 0.92 0.53 0.31 0.35 0.30 0.38 0.28 0.27 0.28

AGE(Yea’s) AT ENDOF INTERVAL

1 10 15 20 25 30 35 40 45 50 55 60.2

---+

-

- f--- + 11

15 BOYS

05 10 15 20 25 30 35 40 45 50 55 65 AGE (Yea’s(AT END OFINTERVAL

Fig 7. Selected percentiles for 6-month increments in

head circumference for boys (birth to 6 years).

ated with mental retardation and neunologic signs’2

and benign subdural effusion.26

A head circumference value outside the normal

range (±2 SD) can be adjusted for prematurity27

(on reference data specific for premature infants

can be used),28’29 head shape,’7’3#{176}recumbent length,

weight,3’ or parental head circumference.32 Such

adjustments remove the effects of these variables

from unusual head circumferences and thus help

determine whether these values are indicative of

abnormalities or diseases.

7

10 15 20 25 30 35 5

AGE (Y.wS)AT ENDOF WITERVAL

Fig 8. Selected percentiles for 6-month increments in

head circumference for girls (birth to 6 years).

ACKNOWLEDGMENT

This research was supported by a grant from Ross

(7)

Education, and Welfare Publication No. (PHS) 78-1650.

Government Printing Office, 1977

3. Hamill PVV, Drizd TA, Johnson CL, et al: Physical growth:

National Center for Health Statistics percentiles. Am J Gun Nutr 1979;32:607-629

4. Nellhaus G: Head circumference from birth to eighteen

years: Practical composite international and interracial

graphs. Pediatrics 1968;41:106-114

5. Roche AF, Himes JH: Incremental growth charts. Am J Gun

Nutr 1980;33:2041-2052

6. Zerfas AJ: The insertion tape: A new circumference tape for

use in nutritional assessment. Am J GUn Nutr

1975;28:782-787

7. SAS User’s Guide, Basic. Raleigh, NC, SAS Institute, 1982,

p 579

8. Rabinowicz T: The differentiate maturation of the human

cerebral cortex, in Falkner F, Tanner JM (eds): Human

Growth, ed 2. New York, Plenum Press, 1986, vol 2, pp 385-410

9. Ounsted M, Moar VA, Scott A: Head circumference charts

updated. Arch J Dis Child 1985;60:936-939

10. Roche AF: Possible catch-up growth of the brain in man.

Acta Med Auxol 1980;12:165-179

1 1. Laron Z, Galatzer A: Effect of hGH on head circumference

and IQ in isolated growth hormone deficiency. Early Hum

Dev 1981;5:211-214

12. Schreier H, Rapin I, Davis J: Familial megalencephaly or

hydrocephalus? Neurology 1974;24:232

13. Baumgartner RN, Roche AF, Himes JH: Incremental

growth tables: Supplementary to previous published charts.

Am J Glin Nutr 1986;43:7711-7722

14. Eichorn DH, Bayley N: Growth in head circumference from

birth through young adulthood. Child Dev 1962;33:257-271

15. Roche AF: Increase in cranial thickness during growth. Hum

Biol1953;25:81-92

16. Young RW: Age changes in the thickness of the scalp in

white males. Hum Biol 1959;31:74-79

17. Brandt I: Dynamics of head circumference growth before

and after term, in RObertS DF, Thomson AM (eds): The

Biology of Human Fetal Growth. London, Taylor & Francis

Ltd, 1976, pp 109-136

18. Karlberg P, Taranger J, Engstrom I, et al: I. Physical growth

from birth to 16 years and longitudinal outcome of the study

during the same age period, in Karlberg P, Taranger G (eds):

The Somatic Development of Children in a Swedish Urban

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Pediatrics

Alex F. Roche, Debabrata Mukherjee, Shumei Guo and William M. Moore