Victora et al’8733 | Maternal education (per year of schooling) 0.73 (0.59 to 0.91) | Birth weight; number of children <5 years; breast feeding; smoking in pregnancy |
| Maternal age (per year) 0.91 (0.84 to 1.00) | |
Kyle et al ’9040 | Maternal age (<20) 1.31 (0.77 to 2.21) | Birth weight; ethnicity; infant sex |
| Social class (IV/V) 1.50 (0.84 to 2.67) | |
| No employed parent 2.34 (1.41 to 3.89) | |
Nordstrom et al ’9346 | Maternal education (<10 years) 1.3 (0.8 to 2.2) | Maternal age; parity, smoking in pregnancy |
Millar and Hill ’9347 | Maternal age (<20) p<0.001 (OR not given) | Birth weight; parity; pregnancy duration; infant sex |
| Marital status (unmarried) p<0.001 (OR not given) | |
Fujita and Kato ’9448 | Marital status (unmarried) p<0.001 (OR not given) | Birth weight; region; birth order; infant sex |
Kilkenny and Lumley’9450 | Maternal age (<20) 1.62 (1.13 to 2.35) | Birth weight; parity; plurality; gestation; mother’s birthplace; infant sex |
| Marital status (unmarried) 2.81 (2.21 to 3.57) | |
Sanghavi ’9553 | Maternal age (<20) 1.73 (CIs not given) p<0.08 | Birth weight; cigarette and alcohol use in pregnancy; prenatal care; race; method of delivery; gestation; multiple births |
| Maternal education (per year of schooling) 0.80 (CIs not given) p<0.01 | |
Alessandri et al ’9656 | Marital status (single) 0.92 (0.52 to 1.61) | Birth weight; parity; gestation; infant sex |
| Maternal age (<20) 2.42 (0.89 to 6.56) | |
Blair et al’96 (CESDI study)58 | Receipt of income support (UK safety net benefit) 2.81 (1.60 to 4.95) | Smoking in pregnancy; parity; marital status; income; alcohol consumption in pregnancy; thermal environment; maternal education; bed/room sharing |
Kytir and Paky’9759 | Maternal education (low) 1.45 (1.16 to 1.81) | Birth weight; birth order; birth interval |
Brooke et al ’9760 | Maternal age (<27) 2.37 (1.23 to 4.58) | Maternal smoking at time of death; sleeping position; bed sharing; social class; infant sex; gestation; birth weight; breast feeding; thermal environment |
| Deprivation score (high) 2.56 (1.20 to 5.49) | |
| Marital status (unmarried) 1.87 (1.00 to 3.48) | |
Daltviet et al ’9861 | Maternal age (<20) 29.4 (9.0 to 96.5) | Smoking in pregnancy; birth order |
| Marital status 2.3 (1.2 to 4.5) | |
| Paternal unemployment 3.7 (2.3 to 6.0) | |
l’Hoir et al ’9862 | Maternal age 1.32 (1.09 to 1.60) | Smoking in pregnancy; smoking after pregnancy; paternal smoking; marital status; breast feeding; bed sharing; birth weight; alcohol use since infant’s birth |
| Socioeconomic status 2.00 (1.01 to 4.00) | |
Toro and Sotonyi 200166 | Social disadvantage 6.7 (1.3 to 35.7) | Smoking in pregnancy; birth weight; breast feeding; sleeping position; pregnancy interval |
Paris et al 200168 | Marital status (unmarried) 2.0 (1.6 to 2.5) | Smoking in pregnancy; year of birth |
| Maternal age (<20) 3.4 (2.3 to 4.8) | |
Sanderson et al 200269 | Residence in area of poverty 2.33 (1.06 to 5.11) | Maternal smoking status (not stated if in pregnancy or after); maternal depression; gestation |