Table 1. Summary of Characteristics of Included Studies.

Source	Birth Year	Study Design	GA	SGA Definition	No. of Participants	No. of Cases	Outcome Assessment	Matched or adjusted variables	Quality assessment
Uvebrant P. et al. (Sweden)41	1967–1982	case-control	34–36	<−2SD	145	55	Medical records reviewed by physicians	Neonatal wards, GA, sex, birth date and type of delivery	6
Topp M. et al. (Denmark)40	1971–1982	case-control	34–36	<−2SD	1678	53	Cerebral Palsy Register of East Denmark	NA	5
Greenwood C. et al. (Britain)38	1984–1993	case-control	33–36	<−1SD	106	36	Oxford Register of Early Childhood Impairment	Neonatal ward, GA	6
Trønnes H. et al. (Norway)5	1967–2001	cohort	32–36	<−2SD	82702	NA	National Insurance Scheme of Norway	Pregnancy disorders, sociodemographic factors and year of birth	7
Jacobsson B. et al. (Sweden)14	1983–1990	case-control	34–36	<10th	73	24	The 1983–90 birth cohort of the cerebral palsy project in Western Sweden	Time of birth, gestational age, gender delivery ward	6
Liu J. et al. (China)39	1990–1997	cohort	32–36	<10th	4215	105	NA	NA	5
Hirvonen M. et al. (Finland)33	1991–2008	cohort	32–36	<−2SD	46731	385	Medical records and clinical multidisciplinary evaluation from the Hospital Discharge Register ICD-10 codes G80 to G83 in 1996 to 2008; ICD-9 codes 342 to 344 in 1991 to 1995	Time of birth, characteristics of mother, characteristics of delivery, newborn disorders	7