Antenatal risk factors for the early life origins of asthma
| Risk factors for wheeze in childhood | OR (95% CI) | Outcome |
| Maternal stress/stressors17 * | 1.56 (1.36 to 1.80) | Childhood asthma or wheeze |
| Maternal smoking62 * | 1.23 (1.12 to 1.36) | Asthma aged >5 years |
| Socioeconomic status63 * | 1.38 (1.37 to 1.39) | Asthma prevalence |
| Low birth weight64 * | 1.13 (1.01 to 1.27) | School-aged asthma |
| Maternal history of asthma* Paternal history of asthma65 * | 3.15 (2.53 to 3.93) 2.60 (2.28 to 2.96) | Asthma aged >5 years |
| Prematurity (22–31 weeks)* Prematurity (32–36 weeks)23 * | 4.92 (2.91 to 8.31) 2.04 (1.38 to 3.01) | Asthma aged 6–9 years |
| Exposure to inhaled pollutants33 | 1.28 (1.15 to 1.41) | Diagnosed asthma by 6 years (male only) |
| Emergency caesarean section* Elective caesarean section66 * | 1.18 (1.07 to 1.29) 1.23 (1.20 to 1.26) | Childhood asthma |
| Caesarean section without medical indication67 | 1.58 (1.17 to 2.13) | Asthma aged 4–12 years |
| Pre-eclampsia68 | 1.23 (1.07 to 1.43) | Ever or recurrent wheeze (up to 24 months) |
| Maternal obesity (BMI≥30 kg/m2)69 | 1.36 (1.08 to 1.68) | Current asthma or wheeze (14 months to 16 years) |
*Asterisk labelled references are the most recently published systematic reviews or metanalyses for antenatal risk factors. Non-asterisked references are case series addressing risk factors for which there are no published systematic reviews.
BMI, body mass index.