Table 1 An overview of the included studies

Upadhyay (2020)/ India [47] 

IQ and Executive Functioning/ Wechsler

Intelligence Scale for children- Crichton Vocabulary (WISC-CVS) (IQ) and Neuropsychological test battery-II (NEPSY II) for executive functioning

Baseline = 12–36 months

Endline = 5–6 years

741

Wealth quintile, number of living children in the family, mother’s years of schooling, father’s years of schooling, father’s occupation

Sokolovic (2014)/ India [18]

Cognitive functioning (IQ)/ Wechsler Intelligence scale of children (WISC/-R/-III)

Baseline = 6 years

Endline = 12 years

1,040

Child’s age, and child’s gender

Nguyen (2021)/ Vietnam [44]

Cognitive functioning (IQ) and mental health/ Wechsler Intelligence Scale for Children for Intellectual functioning for IQ and

Strengths and Difficulties Questionnaire (SDQ) for mental health

Baseline = 2 years

Endline = 7 years

1,392

Maternal (age, parity, and education) and child factors (age, sex, and preschool education), home environment, SES, treatment group, body mass index (BMI) z-scores

Fink (2014)/ India, Peru, Vietnam, Ethiopia [49]

Academic performance; Maths skills; Verbal skills / Peabody Picture Vocabulary Test (PPVT) (Verbal)

Baseline = 8 years Endline = 15 years

3,722

Sex of child, household wealth, caregiver’s age and education

Cheung (2010)/ Philippines [38]

Cognitive functioning (IQ)/ Philippines Non-Verbal Intelligence Test

Baseline = 24 months

Endline = 11 years

1,973

Child’s age and gender

Ocansey (2019)/ Ghana [45]

Cognition; motor; language; socio-emotional functioning / NEPSY‐II (cognition and language), NIH toolbox 9-hole pegboard test (motor), SDQ (socioemotional)

Baseline = 18 months

Endline = 4–6 years

966

Child age, sex, nulliparity, maternal age, education, height, pre‐pregnancy BMI, marital status, household asset score, household food insecurity index, family care indicator scores, child stimulation (HOME) score, preschool attendance, maternal depressive

symptoms and maternal IQ

Poveda (2021) / (Brazil, Guatemala, India, Peru, Philippines and South Africa) [46]

Cognitive functioning (IQ); schooling attainment (Number of years)/ Raven Standard Progressive Matrices for Guatemala, Philippines, South Africa) and WISC for Brazil and Peru);

Baseline = 24 months

Endline = 6–9 years

9,503

Maternal measures of height, age of childbirth, and maternal schooling, child

birth order, income/wealth quintile

Yang (2011)/ Belarus [39]

IQ and verbal scores; psychosocial behaviours, total difficulties (externalizing, internalizing and pre-social behavior)/ Wechsler Abbreviated Scales of Intelligence (WASI) (IQ and verbal scores), Strengths and Difficulties questionnaire (SDQ) for psychosocial behaviours

Baseline = 12 months

Endline = 5 years

Cognitive assessment at

 = 6.5 years

11,899

Sex, gestation (early term/term/post-term), maternal smoking and drinking during pregnancy, duration of breastfeeding, number of older children, parental marital status, parental education and occupation, and parental height, BMI and growth trajectory

Pongcharoen (2012) /Thailand [40]

IQ and verbal scores/ Wechsler Intelligence Scale (IQ/verbal) for Children and the Raven's Colored Progressive Matrices (Pearson) (IQ)

Baseline = 12 months

Endline = 9 years

560

Sex, maternal height, mother’s education,

socioeconomic status, and location of school

Sunny (2018) /Malawi [50]

School performance (Assessed by a Age-for-grade metric that indicates how many years a child is either ahead of or behind their expected grade level in school, calculated by subtracting their current age from their current grade level, minus 5. This measure offers a comprehensive assessment of a student's educational progress, regardless of the highest grade they have reached)

Baseline = 4 years

Endline = 8 years

1,044

Father’s education, mother’s education, household asset index at birth, gender of child and household asset index

Sachdev (2020)/ India [15]

Human capital Metrics (HCM): defined through three metrics: educational status, male occupation, and material possession score

Baseline = 24 months

Endline = 5 years

1,184

Socioeconomic status, utilization of health services, maternal and paternal education, paternal occupation, household income, housing condition, and water and sanitation facilities

Adair (2013)/ Brazil, Guatemala, India, Philippines, and South Africa [51]

Completion of secondary school (assessed by the years of the schooling)

Baseline = 24 months

Endline = 6–9 years

8,362

Mother’s education and household wealth

Crookston (2010)/Peru [42]

Cognitive functioning (IQ)/ cognitive development assessments (CDAs)

Baseline = 4.5 years

Endline = 6 years

1,649

Wealth index and number of siblings

Crookston (2013)/ India, Peru, Vietnam, Ethiopia [52]

Academic performance: mathematics performance; reading comprehension and receptive vocabulary / Early Grade Reading Assessment (reading comprehension),Peabody Picture Vocabulary test (receptive vocabulary)

Baseline = 6 years Endline = 12 years

8,062

Sex of the child, age of the mother, years of schooling of the mother, years of schooling of the father, asset index, urban residence, presence of a community hospital

Casale (2016) /South Africa [16]

Cognitive functioning (IQ)/ Revised Denver Pre-screening Developmental Questionnaire

Baseline = 2 years

Endline = 5 years

666

Sex of child, birth weight; SES; birth order, Home environment; Mother/ caregiver inputs in playing/teaching with child

Berkman (2002)/ Peru [41]

Cognition functioning (IQ)/ Weschler’s scale

Baseline = 12 months

Endline = 9 years

143

Parental education, child’s grade level (grades 3,4, and 5, combined to reference category), child ever held back in class, and child’s school type

Georgiadis (2017)/ Ethiopia, India, Peru, Vietnam [17]

Mathematics scores and language scores/ Peabody Picture Vocabulary Test (PPVT) (language)

Baseline = 1-year Endline = 12 years

4,723

Ethiopia(1,159), India(1,104),Peru(1,129) and Vietnam(1,331)

Child gender, birth order, child age, caregiver's age at childbirth, ethnicity, and schooling, father's schooling, household monthly per capita expenditure

Sowan (2016)/ Thailand [43]

Cognitive functioning (IQ)/ Nonverbal Intelligence 3rd Edition (TONI-III)

Baseline (HAZ) = 3 years

Endline (HAZ) = 5 years

Cognitive score at 8.5 years

1,061

Sex, mother’s education, mother’s age, family income, religion, LBW

Gandhi (2011)/

Malawi [53]

Highest school grade completed, number of times repeating a school grade and mathematics scores

Baseline = 1.5- 5 years

325

child’s gender, gestational duration, father’s (occupation and literacy), mother’s literacy and wealth index

Glewwe (2001)/ Philippines [54]

Cognitive functioning (IQ)/ Philippines Non-verbal Intelligence test

Baseline = 2 years

Endline = 8 years

1,911

Maternal measures of height, age of childbirth, and maternal schooling, child

birth order, income/wealth quintile

Prado (2022)/ Indonesia [48]

Cognitive functioning, and socioemotional scores/ Brief Infant–Toddler Social and Emotional Assessment (Cognitive functioning), Child Behavior Checklist(socioemotional scores)

Baseline = 3.5 years

Endline = 9–12 years

359

Child’s gender, socioeconomic

status, maternal and paternal years of education, and intervention group