Table 1. Characteristics of the included studies, ordered by gestational age categories and age of participant testing.
Author, Year
(country) |
Study design,
total n |
GA (n) | Control
(n) |
Age
assessed (yrs) |
Exclusions | Exposure
measurement |
Cognitive outcomes * | Adjustment |
---|---|---|---|---|---|---|---|---|
Comparison within term (37-42 weeks) | ||||||||
Espel
et al. 2014
18
(USA) |
Longitudinal
prospective study N = 232 |
37-41
(232) |
- | 1 | Preterm birth (<37 weeks), Post
term birth (>41 weeks) |
GA measured from LMP
And Ultrasound |
BSID II assessed by
trained clinicians, no blinding |
Maternal ethnicity
Marital status Fetal Sex Obstetric complications Maternal education Parity Socio-economic status Birth weight percentile |
Rose
et al. 2013
19
(Chile) |
Prospective
cohort from an RCT N = 1,562 |
37-42
(1562) |
- | 1 | Infants born at >42 weeks
gestation, birth weight <3kg |
GA based on LMP | BSID II performed by
trained psychologists, blinding not reported |
Fetal sex
Socio-economic status Birthweight |
Gyamfi
Bannerman et al. 2014 21 (USA) |
Prospective
cohort study N = 20,093 |
37-42
(18,242) |
4 | Parents with mental retardation or
alcohol or drug use |
Not reported | Full-scale IQ scores from
the Stanford-Binet IQ |
Maternal age
Maternal education Socio-economic status Smoking |
|
Yang
et al. 2009
20
(Belarus) |
Prospective
cohort from an RCT N = 13,824 |
37 (469)
38 (2100) 42 (171) 43 (10) |
39-41
(11, 074) |
6.5 | Birth weight <2500g | GA from hospital
records, 94% confirmed by ultrasound |
Full-scale IQ from WASI
scores performed by trained pediatricians |
Maternal age
Marital status Maternal education Parity Smoking Maternal height Parental occupation |
Late preterm vs
term (34 – 36+6) |
||||||||
Nepomnyaschy
et al. 2011 22 (USA) |
Prospective
cohort study N = 5450 |
34-36
(400) |
37-41
(5050) |
2 | Mothers <15 yrs, congenital
anomalies, multiple births |
GA measured by
maternal estimated LMP |
General, BSID II
(converted to a percentile) mental ability, Language by trained interviewer blinded to GA |
Maternal ethnicity
Maternal age Marital status Fetal sex Obstetric complications Maternal Education Parity Socio-economic status Smoking |
Romeo
et al.
2015 23 (Italy) |
Prospective
cohort study N -= 119 |
34-36
(71) |
37-41
(48) |
2 | Abnormal cranial Ultrasound,
congenital malformations, SGA |
Not reported | MDI of BSID II at 2 yrs
Blinding and interviewer training not reported |
Fetal sex |
Narberhaus
et al.
2007 24 (Spain) |
Case Control
study N = 64 |
34-36
(11) |
37-41
(53) |
13-14 | Mental or physical disability,
perinatal complications/hypoxic risk |
Not reported | General WISC full scale
assessed by the same psychologist |
Matched by:
Maternal ethnicity Maternal age Fetal sex Maternal education Socio-economic status |
*Cognitive Outcomes (details in Supplementary File 4): BSID-II = Bayley Scales of Infant Development (2 nd Edition); MDI = Mental Developmental Index, PDI = Psychomotor Developmental Index, WISC = Wechsler Intelligence Scale for Children, WASI = Wechsler Abbreviated Scale of Intelligence