Table 3.
Risk of bias assessments of included studies
| Authors | Confoundersadjusted | Risk of biases | ||||||
|---|---|---|---|---|---|---|---|---|
| Selection | Exposureassessment | Outcomeassessment | Confounderadjustment | Analytical | Attrition | Overall | ||
| Rylanderet al. (24) | Year ofbirth,gender, ma-ternal age, parity,marital status,and smokinghabits in earlypregnancy | Low | Moderate | Low | None | None | Can’t tell | Moderate |
| Rylanderet al. (25) | Gender, maternalage, parity,andsmoking habitsin early preg-nancy | Low | Moderate | Low | None | None | None | Moderate |
| Smallet al. (26) | Maternal age atconception, ageat menarche, andprior infertility | Moderate | None | Low | Low | None | None | Low |
| Tsukimoriet al. (11) | Age at delivery | Low | None | Low | Low | None | Low | Low |
| Vinceti et al. (35) | Age and calendar year | Low | Moderate | None | Low | Low | Low | Moderate |
| Karmauset al. (28) | Height andweight of themothers, occupa-tional conditions, smoking, alco-hol consumption,gestational age,parity, complica-tions | Low | Low | None | None | None | None | Low |
| Fitzgeraldet al. (29) | Age ,occupation,sex, race | None | Low | None | Low | Low | None | Low |
| Mastroiacovoet al. (30) | Prenatal history,birth order, parental age, parental occupation,parental chronicdiseases, andfamily history | Low | Low | None | Low | Low | Can’t tell | Low |
| Schnorret al. (31) | Maternal age,Hispanic ethnic-ity, and thyroiddisease medication, mother’seducation andfather’s race. | Low | None | Low | None | None | Moderate | Low |
| Dimich-wardet al. (32) | Gender, mother’sage, father’s age,birth year | Moderate | Low | Low | Low | None | Can’t tell | Moderate |
| Orret al. (33) | Racial/ethnic group, child’s sex, maternal age, prenatal care | Low | Moderate | Low | Low | Low | Low | Moderate |
| Eskenaziet al. (17) | Maternal age,education, maternal smoking, and alcohol use, previous parity, history of low birth weight, and spontaneous abortion, body mass index, height, maternal weight gain, gestational age, infant’s sex, and years from pregnancy tointerview | Low | None | None | None | None | Low | Low |
| Kuehnet al. (34) | Maternal and paternal age, maternal smoking and alcohol consumption during pregnancy, prior fetal death, race/ethnicity, maternal education, marital status, parental employment, urban vs. rural residence. | None | Moderate | None | None | None | Low | Moderate |
| Vincetiet al. (35) | Maternal age and education | Low | Low | Low | Low | None | Low | Low |
| Cordieret al. (36) | Infant sex, year, district of birth, socioeconomic characteristics, mother’s residence, maternal age, parental geographical origin, educational level, employment status, treatment for chronic disease, folic acid supplementation, history of urinary tract birth defects, parity, obesity, tobacco and alcohol use, family history | Low | Low | Low | none | None | Low | Low |