Table II.
Maternal age effects.
| Author, year, country | Adjusted risk estimates | Risk factors adjusted for | |
|---|---|---|---|
| de la Rochebrochard and Thonneau (2002), France | Maternal age | AOR (95% CI) | Paternal age, country, number of the pregnancy, time to pregnancy, maternal and paternal smoking, history of miscarriage, history of ectopic pregnancy, history of induced abortion |
| 20–29 | 1.0 (reference) | ||
| 30–34 | 1.76 (1.10–2.82) a | ||
| 35–44 | 6.49 (4.43–9.51) a | ||
| Slama et al. (2003) , France | Maternal age | ARR (95% CI) | Paternal age, area of recruitment |
| 25–29 | 1 (reference) | ||
| 30–34 a | 1.34 (0.81–2.20) a , b | ||
| 35–39a | 2.39 (1.21–4.69) a , b | ||
| ≥40a | 6.23 (1.48–26.17) a , b | ||
| Slama et al. (2005), France | Maternal age | AHR (95% CI) | Paternal age, maternal smoking, maternal alcohol consumption, maternal caffeine consumption, paternal smoking in first trimester |
| <22.5 | 1.27 (1.04–1.55) | ||
| 22.5–27.4 | 1 | ||
| 27.5–32.4 | 0.98 (0.84–1.13) | ||
| 32.5–37.4 | 1.30 (1.03–1.66) | ||
| 37.5–42.4 | 2.63 (1.86–3.71) | ||
| ≥42.5 | 8.80 (4.73–16.73) | ||
| Kleinhaus et al. (2006) , USA | Maternal age | AOR (95% CI) | Parity, time interval from index pregnancy to interview, history of miscarriage |
| 25–29 | 1 (reference) | ||
| 30–34 | 2 (1.68–2.36) b | ||
| ≥35 | 3.77 (3.05–4.68) b | ||
| Maconochie et al. (2007) , UK | Maternal age | AOR (95% CI) | Year of conception, history of miscarriage, history of live birth |
| <25 | 1.09 (0.81–1.45) | ||
| 25–29 | 1 (reference) | ||
| 30–34 | 1.06 (0.85–1.31) | ||
| 35–39 | 1.75 (1.37–2.22) | ||
| ≥40 | 5.16 (3.54–7.52) | ||
| Nguyen et al. (2019) , USA | Maternal age | AOR (95% CI) | Ethnicity, income, marital status, pregnancy intention |
| <20 weeks | |||
| <25 | 0.89 (0.72–1.10) | ||
| 25–29 | 1 (reference) | ||
| 30–34 | 0.98 (0.72–1.33) | ||
| ≥35 | 1.52 (1.04–2.20) | ||
| ≤12 weeks | |||
| <25 | 0.86 (0.69–1.09) | ||
| 25–29 | 1 (reference) | ||
| 30–34 | 0.92 (0.68–1.24) | ||
| ≥35 | 1.66 (1.12–2.44) | ||
aRecalculated from the risk estimates reported for the combinations of paternal and maternal age, as described in the statistical analysis. bRescaled to reference category 25–29, as described in the statistical analysis.