Head circumference is the measurement of the baby’s head around its largest area. The distance from above the eyebrows and ears around to the back of the head is measured. The head circumference reflects the status of the baby’s growth and development corresponding to the baby’s age. It tells us if the baby is advancing adequately for its age or is falling behind. It can also suggest possible genetic and growth abnormalities.
Head circumference during pregnancy is usually measured after 13 weeks using ultrasound. The sonologist will measure the fetus’ highest diameter around the head to calculate the head circumference. Measuring the head circumference during pregnancy can give an idea of the volume of the brain. Post delivery, the head circumference will be measured by the pediatrician using a regular measuring tape.
Know more about fetal and obstetric measurements in this video.
Source: SonoSite
If the baby’s head is larger than normal, it can indicate an underlying problem. The head might be too large due to presence of excess fluid in the baby’s brain, a condition known as hydrocephalus. This can lead to brain damage causing mental and physical health issues.
A small head is known as microcephaly. The head circumference in microcephaly is extremely low. It indicates that the baby’s growth is poor, and there might also be abnormal brain development. There are many genetic conditions that can cause microcephaly. Babies born with microcephaly can show poor intellectual ability, growth rate, delayed motor, and speech functions along with difficulty in balance and coordination. Under some conditions, microcephaly can occur after birth as a result of trauma or complications during delivery. In these cases, the head becomes comparatively smaller as the baby grows.
The head circumference must be measured soon after the baby is born or at least within 24 hours after birth to look for any abnormalities. The pediatrician uses a regular non-stretchable measuring tape and wraps it around the widest diameter around the head. It is usually 1 to 2 finger breadths above the eyebrows and over the ears. 3 readings are taken and the largest reading is taken to be as the final head circumference to the nearest 0.1 cm.
See this video on how to measure head circumference.
The following is a chart for infant’s head circumference measurements upto 36 months for boys and girls given by the CDC.
Males, Birth – 36 Months
Age (in months) |
3rd Percentile Head Circumference (in centimeters) |
5th Percentile Head Circumference (in centimeters) |
10th Percentile Head Circumference (in centimeters) |
25th Percentile Head Circumference (in centimeters) |
50th Percentile Head Circumference (in centimeters) |
75th Percentile Head Circumference (in centimeters) |
90th Percentile Head Circumference (in centimeters) |
95th Percentile Head Circumference (in centimeters) |
97th Percentile Head Circumference (in centimeters) |
0 |
31.48762 |
32.14881 |
33.08389 |
34.46952 |
35.81367 |
37.00426 |
37.97379 |
38.51574 |
38.85417 |
0.5 |
33.25006 |
33.83392 |
34.67253 |
35.93987 |
37.19361 |
38.32125 |
39.24989 |
39.77262 |
40.10028 |
1.5 |
35.78126 |
36.26428 |
36.97377 |
38.07878 |
39.20743 |
40.24987 |
41.12605 |
41.62581 |
41.94138 |
2.5 |
37.5588 |
37.97959 |
38.60724 |
39.60637 |
40.65233 |
41.63968 |
42.48436 |
42.97189 |
43.28181 |
3.5 |
38.89944 |
39.27893 |
39.85123 |
40.77713 |
41.76517 |
42.71455 |
43.53902 |
44.01984 |
44.32733 |
4.5 |
39.95673 |
40.30766 |
40.84114 |
41.71483 |
42.66116 |
43.58358 |
44.39472 |
44.87197 |
45.17877 |
5.5 |
40.81642 |
41.14714 |
41.65291 |
42.48889 |
43.40489 |
44.30801 |
45.11034 |
45.58593 |
45.893 |
6.5 |
41.53109 |
41.84742 |
42.3333 |
43.14204 |
44.0361 |
44.92555 |
45.72225 |
46.19736 |
46.50524 |
7.5 |
42.13521 |
42.44134 |
42.91311 |
43.70245 |
44.58097 |
45.46104 |
46.25443 |
46.72983 |
47.0388 |
8.5 |
42.65253 |
42.95162 |
43.41365 |
44.18964 |
45.05761 |
45.93166 |
46.72349 |
47.1997 |
47.5099 |
9.5 |
43.10009 |
43.39458 |
43.85025 |
44.61764 |
45.47908 |
46.34979 |
47.14142 |
47.6188 |
47.93027 |
10.5 |
43.49049 |
43.7823 |
44.23432 |
44.99694 |
45.85506 |
46.72463 |
47.51714 |
47.99592 |
48.30867 |
11.5 |
43.83332 |
44.12399 |
44.57454 |
45.33549 |
46.19295 |
47.06318 |
47.85744 |
48.33781 |
48.65181 |
12.5 |
44.136 |
44.42679 |
44.87767 |
45.63952 |
46.49853 |
47.37091 |
48.16763 |
48.64972 |
48.96494 |
13.5 |
44.40441 |
44.69639 |
45.14908 |
45.91398 |
46.77638 |
47.65214 |
48.45191 |
48.93584 |
49.25225 |
14.5 |
44.64328 |
44.93733 |
45.3931 |
46.16284 |
47.03018 |
47.91038 |
48.71371 |
49.19955 |
49.51712 |
15.5 |
44.85646 |
45.15333 |
45.61325 |
46.38937 |
47.26295 |
48.14848 |
48.95578 |
49.44362 |
49.76233 |
16.5 |
45.04712 |
45.34746 |
45.81245 |
46.59626 |
47.47721 |
48.36881 |
49.18045 |
49.67034 |
49.99018 |
17.5 |
45.2179 |
45.52229 |
45.99315 |
46.78578 |
47.67504 |
48.57336 |
49.38963 |
49.88166 |
50.20261 |
18.5 |
45.37104 |
45.67997 |
46.15739 |
46.95981 |
47.85821 |
48.76379 |
49.58497 |
50.07919 |
50.40125 |
19.5 |
45.50843 |
45.82234 |
46.30692 |
47.11999 |
48.02822 |
48.94153 |
49.76786 |
50.26432 |
50.58751 |
20.5 |
45.63169 |
45.95096 |
46.44325 |
47.26769 |
48.18637 |
49.10781 |
49.93948 |
50.43825 |
50.76259 |
21.5 |
45.74221 |
46.06719 |
46.56767 |
47.40413 |
48.33377 |
49.2637 |
50.10089 |
50.60203 |
50.92752 |
22.5 |
45.84121 |
46.17221 |
46.68129 |
47.53035 |
48.4714 |
49.4101 |
50.25298 |
50.75654 |
51.08322 |
23.5 |
45.92974 |
46.26704 |
46.78511 |
47.64724 |
48.60011 |
49.54784 |
50.39655 |
50.90258 |
51.23047 |
24.5 |
46.00872 |
46.35259 |
46.87997 |
47.75563 |
48.72065 |
49.67762 |
50.53229 |
51.04085 |
51.36998 |
25.5 |
46.07898 |
46.42963 |
46.96663 |
47.85621 |
48.83367 |
49.80008 |
50.66082 |
51.17196 |
51.50236 |
26.5 |
46.14124 |
46.49889 |
47.04578 |
47.94962 |
48.93976 |
49.91578 |
50.78269 |
51.29647 |
51.62817 |
27.5 |
46.19614 |
46.56098 |
47.11801 |
48.0364 |
49.03945 |
50.02521 |
50.89839 |
51.41485 |
51.7479 |
28.5 |
46.24425 |
46.61646 |
47.18385 |
48.11707 |
49.13321 |
50.12883 |
51.00836 |
51.52756 |
51.86198 |
29.5 |
46.2861 |
46.66583 |
47.24379 |
48.19206 |
49.22146 |
50.22705 |
51.113 |
51.63499 |
51.97081 |
30.5 |
46.32214 |
46.70954 |
47.29824 |
48.26178 |
49.30458 |
50.32023 |
51.21268 |
51.73749 |
52.07475 |
31.5 |
46.3528 |
46.74801 |
47.34761 |
48.3266 |
49.38292 |
50.40869 |
51.3077 |
51.83539 |
52.17413 |
32.5 |
46.37844 |
46.78159 |
47.39225 |
48.38684 |
49.45678 |
50.49275 |
51.39837 |
51.92898 |
52.26923 |
33.5 |
46.39942 |
46.81061 |
47.43247 |
48.44281 |
49.52645 |
50.57267 |
51.48496 |
52.01853 |
52.36032 |
34.5 |
46.41605 |
46.8354 |
47.46857 |
48.49479 |
49.59218 |
50.6487 |
51.56771 |
52.10429 |
52.44764 |
35.5 |
46.4286 |
46.85621 |
47.50081 |
48.54301 |
49.65423 |
50.72108 |
51.64686 |
52.18646 |
52.53143 |
36 |
46.43344 |
46.86521 |
47.51556 |
48.56578 |
49.68394 |
50.75597 |
51.68514 |
52.22628 |
52.57205 |
Females, Birth – 36 Months
Age (in months) |
3rd Percentile Head Circumference (in centimeters) |
5th Percentile Head Circumference (in centimeters) |
10th Percentile Head Circumference (in centimeters) |
25th Percentile Head Circumference (in centimeters) |
50th Percentile Head Circumference (in centimeters) |
75th Percentile Head Circumference (in centimeters) |
90th Percentile Head Circumference (in centimeters) |
95th Percentile Head Circumference (in centimeters) |
97th Percentile Head Circumference (in centimeters) |
0 |
31.9302 |
32.2509 |
32.75949 |
33.65187 |
34.71156 |
35.85124 |
36.9535 |
37.65138 |
38.1211 |
0.5 |
33.38071 |
33.68744 |
34.17346 |
35.02508 |
36.03454 |
37.11807 |
38.16405 |
38.82535 |
39.27006 |
1.5 |
35.48627 |
35.7756 |
36.23326 |
37.03282 |
37.97672 |
38.98533 |
39.95459 |
40.56517 |
40.97482 |
2.5 |
36.9855 |
37.26522 |
37.70685 |
38.47603 |
39.38013 |
40.34145 |
41.26063 |
41.83732 |
42.22321 |
3.5 |
38.13114 |
38.40561 |
38.83814 |
39.58905 |
40.46774 |
41.39732 |
42.28153 |
42.83396 |
43.2026 |
4.5 |
39.04619 |
39.31814 |
39.74588 |
40.48611 |
41.34841 |
42.25604 |
43.11489 |
43.64924 |
44.00486 |
5.5 |
39.7996 |
40.07086 |
40.49672 |
41.23136 |
42.08335 |
42.97566 |
43.81575 |
44.3363 |
44.68183 |
6.5 |
40.43379 |
40.70567 |
41.13171 |
41.86435 |
42.71034 |
43.59207 |
44.41815 |
44.92803 |
45.26563 |
7.5 |
40.97672 |
41.25016 |
41.67787 |
42.41113 |
43.25429 |
44.12897 |
44.94461 |
45.44619 |
45.77751 |
8.5 |
41.44768 |
41.7234 |
42.15391 |
42.88978 |
43.7325 |
44.60282 |
45.41078 |
45.90591 |
46.23224 |
9.5 |
41.86058 |
42.13913 |
42.5733 |
43.31329 |
44.15743 |
45.0255 |
45.82799 |
46.31815 |
46.64053 |
10.5 |
42.22575 |
42.50755 |
42.94604 |
43.69135 |
44.53837 |
45.40587 |
46.20466 |
46.69106 |
47.01035 |
11.5 |
42.55105 |
42.83643 |
43.27977 |
44.03133 |
44.88241 |
45.75072 |
46.54726 |
47.0309 |
47.3478 |
12.5 |
42.8426 |
43.13182 |
43.58043 |
44.33899 |
45.19508 |
46.06532 |
46.86084 |
47.34255 |
47.65766 |
13.5 |
43.10526 |
43.39853 |
43.85274 |
44.61891 |
45.48078 |
46.3539 |
47.14942 |
47.62991 |
47.94373 |
14.5 |
43.34294 |
43.64042 |
44.1005 |
44.87476 |
45.74308 |
46.61986 |
47.41624 |
47.89613 |
48.20911 |
15.5 |
43.55883 |
43.86066 |
44.32682 |
45.10959 |
45.98487 |
46.86599 |
47.66399 |
48.1438 |
48.4563 |
16.5 |
43.75558 |
44.06186 |
44.53428 |
45.32587 |
46.20858 |
47.0946 |
47.89487 |
48.37505 |
48.68741 |
17.5 |
43.93539 |
44.2462 |
44.72501 |
45.5257 |
46.41622 |
47.30765 |
48.11074 |
48.5917 |
48.90419 |
18.5 |
44.10013 |
44.41553 |
44.90085 |
45.71086 |
46.6095 |
47.50676 |
48.31317 |
48.79526 |
49.10814 |
19.5 |
44.25137 |
44.57142 |
45.06333 |
45.88284 |
46.78989 |
47.69335 |
48.50351 |
48.98703 |
49.30052 |
20.5 |
44.39047 |
44.71521 |
45.21378 |
46.04295 |
46.95863 |
47.86861 |
48.6829 |
49.16814 |
49.48244 |
21.5 |
44.51861 |
44.84806 |
45.35334 |
46.19229 |
47.11681 |
48.0336 |
48.85236 |
49.33955 |
49.65484 |
22.5 |
44.6368 |
44.97099 |
45.48301 |
46.33184 |
47.26538 |
48.18923 |
49.01276 |
49.50211 |
49.81854 |
23.5 |
44.74593 |
45.08487 |
45.60367 |
46.46246 |
47.40516 |
48.33629 |
49.16486 |
49.65657 |
49.97429 |
24.5 |
44.84678 |
45.19047 |
45.71608 |
46.58489 |
47.53688 |
48.47548 |
49.30933 |
49.80358 |
50.12271 |
25.5 |
44.94005 |
45.2885 |
45.82092 |
46.6998 |
47.66118 |
48.60743 |
49.44677 |
49.94373 |
50.26437 |
26.5 |
45.02634 |
45.37954 |
45.91878 |
46.80778 |
47.77865 |
48.7327 |
49.57773 |
50.07751 |
50.39978 |
27.5 |
45.1062 |
45.46415 |
46.01021 |
46.90935 |
47.88979 |
48.85178 |
49.70266 |
50.20541 |
50.5294 |
28.5 |
45.18011 |
45.5428 |
46.09568 |
47.00499 |
47.99506 |
48.9651 |
49.822 |
50.32783 |
50.65362 |
29.5 |
45.24852 |
45.61594 |
46.17562 |
47.09511 |
48.09488 |
49.07308 |
49.93613 |
50.44514 |
50.77281 |
30.5 |
45.31181 |
45.68394 |
46.25043 |
47.18009 |
48.18961 |
49.17607 |
50.0454 |
50.55769 |
50.88731 |
31.5 |
45.37035 |
45.74718 |
46.32044 |
47.2603 |
48.2796 |
49.2744 |
50.15012 |
50.66578 |
50.99741 |
32.5 |
45.42444 |
45.80596 |
46.38599 |
47.33603 |
48.36515 |
49.36836 |
50.25058 |
50.76968 |
51.10338 |
33.5 |
45.4744 |
45.86058 |
46.44736 |
47.40757 |
48.44654 |
49.45823 |
50.34704 |
50.86965 |
51.20547 |
34.5 |
45.52047 |
45.9113 |
46.50481 |
47.47518 |
48.52402 |
49.54425 |
50.43974 |
50.96593 |
51.30392 |
35.5 |
45.56291 |
45.95837 |
46.55859 |
47.53911 |
48.59783 |
49.62665 |
50.52889 |
51.05872 |
51.39892 |
36 |
45.58284 |
45.98061 |
46.58417 |
47.56976 |
48.63342 |
49.66656 |
50.5722 |
51.10387 |
51.44519 |
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Disclaimer: The information in the article is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your doctor.
Read: Height And Weight Chart: An Easy Tool to Monitor Your Child’s Health
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