Table 1 Characteristics of the included studies

Chawarska K/ 2011 [37]

Retrospective/ Atlanta/Georgia

Autistic: 64

Normal: 55

Male

Autism: 2.2 ± 0.05

Normal: 2.0 ± 0.7

15–18 months:

ASD 13.6%

Control 11.8%

Boys in autism and control groups had similar HC, weight, and height shortly after birth.

Autistic boys had significantly larger HC than that of TD controls by 9.5–18 months (p < 0.05).

Autistic boys were significantly weighed more by age 11.4 months and remained significant throughout 12, 15, 18, and 24 months (p < 0.05).

Autistic boys were significantly longer by age 4.8 months.

Their height remained significantly above that recorded in TD controls at 6, 9, 12, 15, 18, and 24 months (p < 0.05).

-

Autistic boys experienced generalized overgrowth at 6.5–24 months, from those of TD controls.

Constantino J/ 2009 [80]

Retrospective/USA

Autistic: 48 Control: 85

Male

4–18 years

Not reported

Not reported.

The differences between

the HG rates in the ASD and control groups was significant only at birth-6 months (p = 0.04).

-

-

-

Rate of HG of ASD subjects was slightly accelerated compared to controls, but not significant.

Courchesne E/ 2003 [83]

Prospective/

USA

ASD: 48 (2–5 years)

Male/Female

2–5 year

6–14 months: ASD 53%

Healthy 6%

In ASD infants, birth HC was smaller compared to healthy infants (p < 0.001).

Within the ASD group, excessive increase in HC was accured between 1–2 months and 6–14 months while, only 6% of healthy infants had accelerated HC growth.

Body weight did not differe from healthy infants at any time points.

Body height did not differe from healthy infants at any time points.

-

ASD infants had a reduced head size at birth and a sudden and excessive increase in head size between 1–2 months and 6–14 months.

Daniel J/ 2014 [8]

Retrospective/USA

ASD: 200

Normal: 147

Male/Female

Birth to 2 years

At birth (p = 0.65):

ASD 1.0%

TD 2.0%

At 24 months (p = 0.47):

ASD 6%

TD 4.1%

There was no statistically significant difference between boys and girls with ASD and TD controls in HC, weight, and height at birth.

Between 10.7–22.8 months, boys with ASD had significantly larger HC than TD boys (p < 0.05). No statistically significant differences in HC were observed in girls with ASD compared to TD girls at any age.

Autistic boys were significantly heavier than TD boys by 8.7 months, with the difference by 24 months. Girls with autism and PDDNOS

showed a similar albeit nonsignificant trend, becoming heavier than TD girls by 0.70 kg by 24 months.

Autistic boys grew significantly longer than TD boys by 3.6 months. Girls with ASD showed a slight increasing trend, becoming on average 0.77 cm taller than TD girls by 24 months, these effects were not statistically significant.

Gestational

age

Boys but not girls with ASD were larger and exhibited an increased rate of extreme EGO compared to community controls

Dawson G/ 2007 [82]

Retrospective/USA

ASD: 28

Male

37–52 months

Not reported

Not reported

HC z-scores relative to norms significantly increased in the autism sample from birth to 12 months (p < 0.001), but this pattern did not persist beyond 12 months.

-

Length/height is significantly related to HC; children who are longer/taller tend to have larger heads.

Height

A period of exceptionally rapid HG occurs during the first year of life in autism; after 12 months of age, the rate of HC growth decelerates relative to the rate during the first year of life.

Dementieva Y/ 2004 [21]

Retrospective/USA

ASD: 251

Male/Female

3–21 years

Average age 8.15 ± 4.43

Birth to 12 months (p < 0.0001):

ASD 19% (66% males and 34% females)

The general population 3.0%

Not reported

There as an abnormal acceleration in HG during the first and second months of life in a subgroup of autistic individuals.

-

-

Multiple comparison adjustments-familial similarities

-

Fukumoto A/ 2008 [83]

Retrospective/Japan

ASD: 85

Male/Female

-

Not reported

The HC, weight, and height at birth of autistic children was similar to that of the average found in control group.

HC increased at 1 month after birth. The discrepancy reached a peak at 6 months, while the difference became smaller at 12 months.

Boys from the high functioning group

showed significant differences in body weight at 3, 6 and

12 months. Boys from the low functioning group (IQ < 70) showed a similar difference at 3 and 12 months.

The body length was significantly greater than the standard values only in the high functioning group (IQ ≥ 70) of boys at 3 months and 6 months.

-

Fukumoto A/2011 [84]

Retrospective/Japan

ASD: 280

Controls: 609

Male/Female

ASD: 7.39 ± 3.64 years

Controls: 7.02 ± 2.56 years

Not reported

At birth, neither HC nor weight significantly

differed between the ASD and control groups

among the males and females.

Only the HC in the male ASD group was significantly increased from 6 to 9 months after birth, reaching a peak at 6 months after birth. No difference was found in the female ASD group.

-

-

Height, weight, and age.

Gillberg Ch/2002 [85]

Retrospective/Sweden

ASD: 50

Male/Female

Mean age: 6 years 4 months

ASD:

Birth 35.5%

After 16 month 26%

Mean OFCs of ASD at birth were larger than normative values (p < 0.05).

26% of children were macrocephalus after age 16 months.

-

-

-

Grandgeorge M/2013 [9]

Retrospective/France

ASD: 422

Control: 153

Male/Female

18 months to 18 years

ASD:

Birth 5.7%

With regard to body length 11.4%

With regard to body weight 7.6%

Control:

Birth 3%

The individuals

with ASD did not significantly differ from the control

group at birth (p > 0.05).

Relative macrocephaly with regard to body length in ASD was significantly higher than the rate in the control group.

-

-

Height and weight,

Hazlett H/2005 [86]

Retrospective/USA

ASD: 51 Control: 25

Males/Females

18–35 months

Not reported

No group

differences between HC ratings were found at birth.

There as a significantly increased rate of HC growth appearing to begin around 12 months of age.

-

-

Age and sex

-

Kral T/2018 [87]

Retrospective/USA

ASD: 668

Control: 884

Male/Female

59.3 ± 6.6 (2–5 years)

Not reported

Not reported

-

ASD children showed the highest frequency of rapid weight gain (44%) and were 3.47 times more likely to be overweight/obese

(p < 0.001).

-

Maternal education, race/ethnicity,

poverty status, birth weight, child age, and sex.

-

Marz K/2007 [22]

Retrospective/USA

ASD: 35

Male/female

ASD: 26.6 months ± 4.5

Control: ages 19 months to 10 years

Not reported

Not reported

Infants with ASD had a significantly smaller HC at birth to 2 weeks and a significantly larger HC by 10 to 14 months. However, when overall length and weight were controlled, HC was not bigger in the ASD group compared to local controls.

Children with ASD

were also significantly heavier beginning at 1 to 2 months.

Children with ASD

were significantly longer beginning at 1 to 2 months.

-

-

McKeague l/2015 [88]

Retrospective/USA

ASD: 468

ASD: 468

Male/Female

5.1 ± 3.4

Not reported

There was not significant difference between birth weight of ASD and control groups.

Growth velocity of HC at 3 months of age, is significantly associated with autism (p = 0.014).

Weight growth velocity at 18 months without ID (p = 0.02) and 24 months without ID (p = 0.042).

Height growth velocity among subjects with autism and without ID is significantly associated with autism at 6 months (p = 0.007).

Maternal age, paternal age, gestational

age, birth weight, previous births, and maternal socioeconomic

status.

Mraz K/2009 [89]

Retrospective/USA

ASD: 24

Control: 37

Male/Female

4 years 10 months to 9 years 8 months

Not reported

Not reported

HC growth were significantly greater in ASD groups compared with controls (p < 0.05).

Weight growth were significantly greater in ASD groups compared with controls (p < 0.05).

Mean length in the ASD group did not differ significantly from controls (p < 0.05).

Sex and age.

Muratori F/2012 [90]

Retrospective/Italy

ASD: 50

Control: 100

Male/Female (40/10)

Mean age: 52 months

6–12 months: ASD 18%

At birth there was no significant difference in HC size between ASD and TD groups.

At 3–12 months HC was significantly greater in ASD group compared to healthy infants, but not at 1–2 months. The HC growth was significantly greater in ASD compared to TD group (p = 0.001)

Weight was significantly smaller in ASD group compared to TD at 1–12 months and no difference was found

on the rate of weight growth (p = 0.655) between the two groups.

No significant differences were found between the two groups (p = 0.491) on the rate of height growth.

Weight and height.

-

Rommelse N/2011 [91]

Retrospective/Netherlands

ASD: 129

Non-ASD psychiatric disorders: 59

Male/Female

(109/20)

0–20 years

There were no differences between the ASD and control groups. ASD:

1–4 months: 1.2%

5–9 months: 1.6%

10–13 months: 4.7%

Both groups had a decreased height

at birth (ASD: p = 0.001; PC: p = 0.02).

ASD children had an increased HC relative to their height at first month (p = 0.001) and 2 months

(p = 0.006).

There was a decreased weight very early in

Development (first month) in both groups (ASD: p = 0.001; PC: p = 0.005).

Both groups had a decreased height

at 1 month of age (ASD: p = 0.001; PC: p = 0.005).

Sex and age.

Neither group showed

abnormal acceleration of HC or weight,

but both groups showed a significant abnormal acceleration

of height between birth and 14–19 months of age.

Schrieken M/2013 [10]

Retrospective/Netherlands

ASD: 96

Control: 163

Male/Female

(81.2% boys)

1–3 years

Not reported

ASD children had somewhat smaller HC at birth than control children.

With increasing age, children with ASD had a proportionally smaller HC compared to their height (p = 0.003) the first 13 months of life.

-

-

Height

-

Suren P/2013 [92]

Prospective/United Kingdom

ASD:376

Male/Female

(310/66)

3.6–13.1 years (mean 7.4 years)

ASD:

Birth-12 months 4.3–8.7%

At birth, mean HC for boys with ASD was close to the mean of HC for boys without ASD.

In boys with ASD, mean HG was similar to that of other boys, but variability was greater.

Throughout the first year, the HC of girls with ASD was reduced by 0.5 cm at 12 months.

The mean weight of ASD girls was 150–350 g below at all ages from birth to three years. ASD boys had mean weight 300 g above the control mean at age 12 months.

The mean length of ASD was similar to that of other girls. ASD boys had mean length 1.1 cm above the control mean at age 12 months.

Parental height, parental education, maternal smoking, parity, gestational age at birth, and breastfeeding.

-

Torrey F/2004 [93]

Prospective / Maryland

ASD: 15

Control: 50,000

Male/Female

(11/4)

7 years

ASD:

Birth 13·3%

6–14 months

6·7%

The autistic group had a slightly but not significantly larger HC at birth.

At 4 months, the HC in the autistic group was not significantly larger than that of control subjects.

Body weight was

significantly larger in the autistic group.

Body length was

significantly larger in the autistic group.

-

-

Van Daalen E/2007 [94]

Prospective/ Netherlands

ASD: 53

Control: 22

Male/Female

(44/9

9/13)

3 years

ASD:

1–12 months

11.3%

Not reported

Growth of HC was normal in children with ASD compared with controls in the first year of life.

-

Growth of body length was accelerated

in children with ASD

compared with controls in the first year of life.

-

Accelerated growth

between 1–6 months.

Webb S/2007 [95]

Prospective/ USA

ASD: 28

With developmental delay without autism: 8

Male

3–4 years

ASD:

Birth-36 months 21.4%

Occipitofrontal circumference of ASD did not differ frome normal values.

Compared with the normal values, occipitofrontal circumference

for the ASD group was statistically significantly smaller at age 1 to 6.99 months (p < 0.005) but not at birth to age 0.99 months or from age 7 to 36 months.

-

Compared with normal values for height, the ASD group, on average, was statistically significantly longer or taller than the norms only during the first month of life.

Bonferroni adjustment

Rate of growth from birth to age 36 months was statistically significantly

higher for the ASD group than the developmental delay group.

Raghavan R/ 2018 [56]

Prospective/ Maryland

ASD: 822

Male/Female

5.2–9.8 years

Not reported

Birthweight was significantly higher in control than in ASD group (p = 0.03).

-

Extremely rapid weight gain during infancy was associated with a greater ASD risk

(OR: 3.11; 95% CI: 1.37, 7.07).

-

Maternal age at delivery, smoking during maternal status, child’s sex, gestational age at birth, year of the baby’s birth, and mode of feeding.

-