Table 3 Risk of adverse outcomes associated with advanced maternal age (compared with women aged 30–34 years) stratified analysis by conception method and parity

35–39

1.19 (1.12–1.27)

1.18 (1.17–1.20)

1.30 (1.25–1.31)

1.12 (1.10–1.14)

40–44

1.49 (1.40–1.59)

1.38 (1.35–1.41)

1.66 (1.60–1.70)

1.22 (1.19–1.26)

45–49

1.71 (1.45–2.01)

1.49 (1.33–1.67)

2.13 (1.92–2.37)

1.10 (0.93–1.30)

p for trend

<0.001

<0.001

<0.001

<0.001

Emergency cesarean section

35–39

1.15 (1.04–1.27)

1.16 (1.13–1.19)

1.21 (1.17–1.24)

1.11 (1.07–1.15)

40–44

1.20 (1.07–1.34)

1.41 (1.35–1.47)

1.46 (1.40–1.54)

1.28 (1.20–1.36)

45–49

1.25 (0.87–1.80)

1.71 (1.41–2.08)

1.74 (1.41–2.14)

1.39 (1.03–1.89)

p for trend

0.001

<0.001

<0.001

<0.001

Preeclampsia

35–39

1.11 (0.87–1.43)

1.27 (1.19–1.34)

1.20 (1.11–1.30)

1.37 (1.25–1.50)

40–44

1.12 (0.84–1.50)

1.53 (1.39–1.69)

1.24 (1.09–1.42)

1.82 (1.60–2.08)

45–49

1.57 (0.71–3.47)

2.48 (1.66–3.70)

1.33 (0.72–2.45)

3.62 (2.34–5.61)

p for trend

0.294

<0.001

<0.001

<0.001

Severe-preeclampsia

35–39

1.19 (0.80–1.77)

1.26 (1.14–1.39)

1.23 (1.08–1.39)

1.33 (1.13–1.55)

40–44

1.13 (0.71–1.80)

1.51 (1.28–1.79)

1.20 (0.96–1.49)

1.84 (1.46–2.32)

45–49

2.82 (1.05–7.58)

1.51 (0.63–3.63)

1.69 (0.71–3.99)

2.31 (0.86–6.21)

p for trend

0.293

<0.001

0.002

<0.001

Placenta previa

35–39

1.07 (0.85–1.35)

1.25 (1.16–1.34)

1.33 (1.20–1.48)

1.17 (1.07–1.28)

40–44

1.10 (0.84–1.45)

1.44 (1.27–1.62)

1.45 (1.22–1.71)

1.33 (1.15–1.55)

45–49

1.11 (0.42–2.94)

2.60 (1.59–4.27)

2.31 (1.25–4.28)

1.98 (1.04–3.75)

p for trend

0.487

<0.001

<0.001

<0.001

35–39

2.08 (1.20–3.59)

1.09 (0.97–1.21)

1.26 (1.07–1.47)

1.04 (0.90–1.19)

40–44

0.85 (0.39–1.84)

1.18 (0.98–1.43)

1.05 (0.78–1.42)

1.14 (0.90–1.44)

45–49

1.79 (0.24–13.2)

1.69 (0.71–4.03)

1.36 (0.34–5.48)

1.76 (0.67–4.64)

p for trend

0.989

0.027

0.054

0.231

Preterm birth (<37w)

35–39

0.90 (0.81–1.12)

1.04 (1.01–1.07)

1.03 (0.99–1.07)

1.04 (1.01–1.08)

40–44

0.76 (0.65–0.88)

1.13 (1.08–1.18)

1.04 (0.97–1.12)

1.12 (1.06–1.19)

45–49

0.87 (0.52–1.44)

1.16 (0.90–1.50)

1.25 (0.90–1.73)

1.01 (0.74–1.40)

p for trend

0.001

<0.001

0.104

<0.001

Very preterm birth (<32w)

35–39

0.82 (0.64–1.06)

1.03 (0.97–1.11)

1.01 (0.92–1.12)

1.03 (0.95–1.13)

40–44

0.60 (0.42–0.86)

1.10 (0.99–1.23)

0.98 (0.83–1.16)

1.08 (0.95–1.24)

45–49

0.57 (0.14–2.25)

0.84 (0.42–1.68)

1.24 (0.59–2.62)

0.44 (0.14–1.34)

p for trend

0.004

0.108

0.945

0.357

Extremely preterm birth (<28w)

35–39

0.66 (0.43–1.00)

0.99 (0.88–1.12)

0.97 (0.82–1.15)

0.97 (0.83–1.13)

40–44

0.48 (0.26–0.87)

0.93 (0.76–1.23)

0.76 (0.56–1.03)

0.97 (0.76–1.23)

45–49

–

0.31 (0.04–2.17)

0.47 (0.07–3.32)

–

p for trend

0.005

0.452

0.120

0.513

Low birthweight

35–39

0.99 (0.89–1.10)

1.03 (1.01–1.06)

1.04 (1.01–1.08)

1.02 (0.99–1.06)

40–44

0.89 (0.78–1.01)

1.12 (1.08–1.17)

1.04 (0.98–1.10)

1.14 (1.08–1.20)

45–49

0.98 (0.63–1.51)

1.24 (1.01–1.52)

1.15 (0.87–1.51)

1.23 (0.96–1.58)

p for trend

0.096

<0.001

0.011

<0.001

Small for gestational age

35–39

0.85 (0.68–1.06)

1.03 (0.98–1.08)

1.00 (0.93–1.07)

1.04 (0.98–1.10)

40–44

0.72 (0.54–0.96)

1.12 (1.03–1.22)

0.94 (0.83–1.07)

1.20 (1.08–1.32)

45–49

0.66 (0.22–2.01)

1.44 (0.97–2.13)

1.02 (0.54–1.93)

1.54 (0.97–2.44)

p for trend

0.019

0.005

0.546

0.001

Low Apgar (5 min, <7)

35–39

0.85 (0.62–1.17)

1.03 (0.96–1.11)

1.06 (0.95–1.17)

1.00 (0.91–1.10)

40–44

0.71 (0.48–1.07)

1.14 (1.01–1.30)

0.99 (0.82–1.20)

1.18 (1.01–1.39)

45–49

0.43 (0.06–3.03)

0.61 (0.23–1.60)

0.24 (0.03–1.71)

0.90 (0.34–2.37)

p for trend

0.069

0.092

0.835

0.179

Low pH of umbilical cord artery (<7.1)

35–39

0.94 (0.58–1.51)

1.12 (1.01–1.24)

1.03 (0.89–1.19)

1.20 (1.04–1.39)

40–44

1.23 (0.72–2.10)

1.24 (1.04–1.49)

1.20 (0.95–1.52)

1.33 (1.04–1.68)

45–49

–

1.52 (0.64–3.64)

1.34 (0.44–4.14)

1.02 (0.25–4.09)

p for trend

0.689

0.003

0.185

0.003

Perinatal death

35–39

0.71 (0.38–1.31)

1.02 (0.90–1.16)

0.97 (0.80–1.17)

1.04 (0.88–1.23)

40–44

0.60 (0.27–1.34)

1.11 (0.88–1.39)

1.08 (0.78–1.50)

1.05 (0.78–1.41)

45–49

–

1.87 (0.71–4.93)

0.83 (0.12–5.86)

2.11 (0.69–6.49)

p for trend

0.137

0.326

0.910

0.485