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. 2019 Feb 20;9:2365. doi: 10.1038/s41598-019-38999-5

Table 2.

Risk of neonatal outcomes associated with maternal age categories (versus aged 20–24 years).

Outcome Maternal age Women with complete data (n = 30,831)
Crude RR Multivariate model 1a Multivariate model 2b
Preterm birth (<37weeks)
 All adolescents 1.09 (1.00–1.18) 1.17 (1.08–1.27) 1.16 (1.07–1.26)
 Junior adolescent 1.14 (0.74–1.74) 1.22 (0.81–1.82) 1.18 (0.79–1.76)
 Senior adolescent 1.09 (1.00–1.18) 1.17 (1.08–1.27) 1.15 (1.06–1.25)
Very preterm birth (<32weeks)
 All adolescents 1.18 (0.99–1.39) 1.32 (1.11–1.56) 1.31 (1.10–1.55)
 Junior adolescent 1.02 (0.39–2.67) 1.12 (0.45–2.80) 1.08 (0.43–2.72)
 Senior adolescent 1.18 (1.00–1.40) 1.33 (1.12–1.57) 1.31 (1.10–1.55)
Extremely preterm birth (<28weeks)
 All adolescents 1.30 (0.99–1.70) 1.39 (1.06–1.83) 1.39 (1.06–1.83)
 Junior adolescent 1.39 (0.35–5.51) 1.46 (0.37–5.71) 1.42 (0.36–5.55)
 Senior adolescent 1.29 (0.98–1.70) 1.39 (1.05–1.84) 1.38 (1.04–1.82)
Small for gestational age
 All adolescents 0.92 (0.80–1.07) 0.92 (0.79–1.07) 0.88 (0.76–1.03)
 Junior adolescent 0.96 (0.44–2.09) 0.90 (0.42–1.94) 0.82 (0.38–1.77)
 Senior adolescent 0.92 (0.79–1.07) 0.92 (0.79–1.07) 0.89 (0.76–1.03)
Low birth weight
 All adolescents 1.05 (0.98–1.13) 1.08 (1.01–1.15) 1.05 (0.98–1.12)
 Junior adolescent 1.05 (0.73–1.50) 1.03 (0.74–1.44) 0.97 (0.69–1.35)
 Senior adolescent 1.05 (0.98–1.13) 1.08 (1.01–1.15) 1.05 (0.98–1.12)
Low Apgar (5 min, <7)
 All adolescents 1.37 (1.12–1.67) 1.41 (1.15–1.73) 1.41 (1.16–1.73)
 Junior adolescent 2.00 (0.84–4.73) 2.06 (0.87–4.89) 2.03 (0.85–4.84)
 Senior adolescent 1.35 (1.10–1.66) 1.39 (1.13–1.71) 1.39 (1.13–1.71)
IUFD/Early neonatal death
 All adolescents 1.03 (0.69–1.52) 1.06 (0.71–1.59) 1.07 (0.71–1.60)
 Junior adolescent none
 Senior adolescent 1.06 (0.71–1.57) 1.10 (0.73–1.64) 1.09 (0.73–1.64)

Junior adolescent: Women aged ≤15.

Senior adolescent: Women aged 16–19.

All adolescent: Women aged ≤19.

aAdjusted by parity, pre-pregnancy BMI, gestational weight gain, maternal smoking, pre-existing hypertension, pre-existing diabetes or gestational diabetes, and year of delivery.

bAdjusted by parity, pre-pregnancy BMI, gestational weight gain, maternal smoking, preexisting hypertension, preexisting diabetes or gestational diabetes, year of delivery, and maternal height.