Obstetric outcome data in singleton primiparous women in the period 1992–2010 in relation to maternal age group
| Characteristics | Crude OR (95% CI) | aOR (95% CI)* | Crude OR (95% CI) | aOR (95% CI)* | Crude OR (95% CI) | aOR (95% CI)* |
|---|---|---|---|---|---|---|
| Labour | <17 years | 17–19 years | 20–24 years | |||
| Spontaneous onset labour | 1.20 (1.07 to 1.35) | 1.20 (1.05 to 1.37) | 1.28 (1.24 to 1.33) | 1.26 (1.21 to 1.31) | 1.16 (1.14 to 1.17) | 1.16 (1.14 to 1.18) |
| Induced labour | 0.73 (0.63 to 0.85) | 0.78 (0.66 to 0.93) | 0.81 (0.78 to 0.85) | 0.86 (0.82 to 0.90) | 0.90 (0.89 to 0.92) | 0.91 (0.90 to 0.93) |
| 30–34 years | 35–39 years | 40+ years | ||||
| Spontaneous onset labour | 0.77 (0.76 to 0.78) | 0.78 (0.77 to 0.79) | 0.50 (0.49 to 0.51) | 0.52 (0.51 to 0.54) | 0.29 (0.26 to 0.30) | 0.30 (0.28 to 0.31) |
| Induced labour | 1.23 (1.21 to 1.26) | 1.19 (1.17 to 1.21) | 1.66 (1.62 to 1.70) | 1.54 (1.50 to 1.58) | 2.17 (2.06 to 2.27) | 1.97 (1.87 to 2.08) |
| Mode of delivery | <17 years | 17–19 years | 20–24 years | |||
| Normal vaginal birth | 2.05 (1.84 to 2.30) | 2.04 (1.79 to 2.32) | 1.95 (1.89 to 2.02) | 1.95 (1.88 to 2.02) | 1.39 (1.37 to 1.41) | 1.39 (1.37 to 1.41) |
| Forceps† | 0.38 (0.18 to 0.81) | 0.41 (0.18 to 0.92) | 0.55 (0.46 to 0.64) | 0.48 (0.39 to 0.59) | 0.82 (0.76 to 0.88) | 0.77 (0.71 to 0.84) |
| Vacuum extraction† | 0.42 (0.36 to 0.51) | 0.43 (0.36 to 0.52) | 0.50 (0.48 to 0.53) | 0.50 (0.48 to 0.53) | 0.74 (0.72 to 0.75) | 0.74 (0.72 to 0.75) |
| CS: all | 0.60 (0.52 to 0.69) | 0.57 (0.48 to 0.67) | 0.56 (0.54 to 0.69) | 0.55 (0.53 to 0.58) | 0.73 (0.72 to 0.74) | 0.72 (0.71 to 0.74) |
| CS elective 1999–2010‡ | 0.95 (0.73 to 1.25) | 0.83 (0.60 to 1.14) | 0.53 (0.48 to 0.59) | 0.53 (0.47 to 0.60) | 0.65 (0.62 to 0.68) | 0.68 (0.65 to 0.71) |
| CS acute 1999–2010‡ | 0.54 (0.43 to 0.68) | 0.53 (0.40 to 0.69) | 0.52 (0.49 to 0.56) | 0.56 (0.52 to 0.61) | 0.68 (0.66 to 0.70) | 0.71 (0.69 to 0.73) |
| 30–34 years | 35–39 years | 40+ years | ||||
| Normal vaginal delivery | 0.70 (0.69 to 0.71) | 0.72 (0.71 to 0.73) | 0.46 (0.45 to 0.47) | 0.48 (0.47 to 0.49) | 0.29 (0.28 to 0.31) | 0.31 (0.30 to 0.32) |
| Forceps† | 1.08 (1.01 to 1.15) | 1.20 (1.12 to 1.29) | 1.48 (1.35 to 1.63) | 1.66 (1.49 to 1.84) | 1.58 (1.27 to 1.98) | 1.75 (1.37 to 2.24) |
| Vacuum extraction† | 1.32 (1.30 to 1.34) | 1.29 (1.27 to 1.32) | 1.72 (1.67 to 1.76) | 1.67 (1.63 to 1.72) | 2.01 (1.90 to 2.13) | 1.92 (1.80 to 2.04) |
| CS: all | 1.46 (1.44 to 1.49) | 1.44 (1.42 to 1.47) | 2.34 (2.29 to 2.38) | 2.21 (2.16 to 2.26) | 4.07 (3.91 to 4.23) | 3.78 (3.61 to 3.96) |
| CS elective 1999–2010‡ | 1.63 (1.57 to 1.68) | 1.44 (1.39 to 1.49) | 2.74 (2.63 to 2.85) | 2.25 (2.15 to 2.35) | 5.03 (4.70 to 5.36) | 3.89 (3.61 to 4.20) |
| CS acute 1999–2010‡ | 1.63 (1.59 to 1.67) | 1.44 (1.40 to 1.47) | 2.41 (2.35 to 2.48) | 1.94 (1.88 to 2.00) | 3.47 (3.29 to 3.66) | 2.68 (2.52 to 2.85) |
| Gestational age (weeks) | <17 years | 17–19 years | 20–24 years | |||
| GA <28 | 3,44 (2.20 to 5.37) | 2.84 (1.59 to 5.06) | 1.46 (1.19 to 1.79) | 1.25 (0.97 to 1.62) | 1.01 (0.90 to 1.14) | 0.89 (0.77 to 1.02) |
| GA <32 | 2.12 (1.55 to 2.91) | 1.66 (1.10 to 2.51) | 1.29 (1.15 to 1.46) | 1.20 (1.04 to 1.38) | 0.96 (0.90 to 1.03) | 0.92 (0.85 to 0.99) |
| GA <37 | 1.55 (1.34 to 1.79) | 1.46 (1.24 to 1.72) | 1.09 (1.04 to 1.15) | 1.03 (0.98 to 1.09) | 0.99 (0.97 to 1.02) | 0.97 (0.95 to 1.00) |
| GA 37–41 | 0.89 (0.79 to 0.99) | 0.88 (0.77 to 0.99) | 1.11 (1.07 to 1.15) | 1.14 (1.09 to 1.18) | 1.10 (2.08 to 1.12) | 1.12 (1.10 to 1.14) |
| GA ≥42 | 0.82 (0.70 to 0.96) | 0.89 (0.75 to 1.06) | 0.77 (0.74 to 0.81) | 0.79 (0.74 to 0.83) | 0.86 (0.84 to 0.88) | 0.85 (0.83 to 0.87) |
| 30–34 years | 35–39 years | 40+ years | ||||
| GA <28 | 1.26 (1.13 to 1.40) | 1.17 (1.04 to 1.33) | 1.88 (1.64 to 2.15) | 1.61 (1.40 to 1.90) | 2.79 (2.19 to 3.56) | 2.48 (1.86 to 3.29) |
| GA <32 | 1.24 (1–17 to 1.32) | 1.24 (1.16 to 1.33) | 1.79 (1.65 to 1.93) | 1.68 (1.53 to 1.84) | 2.44 (2.12 to 2.82) | 2.25 (1.90 to 2.66) |
| GA <37 | 1.04 (1.01 to 1.06) | 1.02 (0.99 to 1.05) | 1.23 (1–19 to 1.27) | 1.19 (1.15 to 1.24) | 1.41 (1.32 to 1.52) | 1.37 (1.26 to 1.48) |
| GA 37–41 | 0.88 (0.86 to 0.89) | 0.89 (0.86 to 0.89) | 0.75 (0.73 to 0.76) | 0.76 (0.74 to 0.78) | 0.81 (0.77 to 0.85) | 0.83 (0.79 to 0.88) |
| GA ≥42 | 1.20 (1.17 to 1.22) | 1.20 (1.18 to 1.23) | 1.36 (1.33 to 1.40) | 1.35 (1.31 to 1.39) | 1.08 (1.01 to 1.15) | 1.06 (0.98 to 1.14) |
| Maternal complications and use of epidural analgesia | <17 years | 17–19 years | 20–24 years | |||
| Perineal laceration grades 1–2† | 0.44 (0.39 to 0.50) | 0.44 (0.38 to 0.50) | 0.46 (0.44 to 0.47) | 0.47 (0.45 to 0.49) | 0.65 (0.64 to 0.66) | 0.68 (0.67 to 0.69) |
| Perineal laceration grades 3–4† | 0.33 (0.22 to 0.49) | 0.39 (0.25 to 0.60) | 0.31 (0.25 to 0.37) | 0.37 (0.32 to 0.42) | 0.57 (0.54 to 0.59) | 0.61 (0.58 to 0.64) |
| Preeclampsia | 0.83 (0.61 to 1.12) | 0.89 (0.62 to 1.27) | 0.89 (0.82 to 0.97) | 0.93 (0.84 to 1.02) | 1.07 (1.03 to 1.12) | 1.01 (0.96 to 1.05) |
| Abruptio placentae | 1.72 (1.05 to 2.83) | 1.76 (1.03 to 3.00) | 1.16 (0.97 to 1.39) | 1.02 (0.83 to 1.26) | 0.89 (0.81 to 0.98) | 0.83 (0.74 to 0.92) |
| Placenta praevia | 0.50 (0.12–2.00) | 0.57 (0.14 to 2.30) | 0.32 (0.19 to 0.53) | 0.28 (0.16 to 0.50) | 0.52 (0.43 to 0.61) | 0.52 (0.43 to 0.63) |
| PPH >1000 mL (VB) | 0.70 (0.54 to 0.89) | 0.65 (0.48 to 0.88) | 0.57 (0.53 to 0.61) | 0.64 (0.59 to 0.70) | 0.71 (0.69 to 0.74) | 0.78 (0.75 to 0.81) |
| PPH >1000 mL (CS) | 0.73 (0.18 to 2.93) | 0.52 (0.07 to 3.74) | 0.87 (0.59 to 1.27) | 1.16 (0.77 to 1.93) | 0.99 (0.92 to 1.07) | 1.09 (0.93 to 1.28) |
| Epidural analgesia† | 1.03 (0.95–1.12) | 1.03 (0.93 to 1.13) | 1.07 (1.06 to 1.08) | 1.07 (1.04 to 1.10) | 1.02 (1.01 to 1.03) | 1.03 (1.01 to 1.04) |
| 30–34 years | 35–39 years | 40+ years | ||||
| Perineal laceration grades 1–2† | 1.33 (1.31 to 1.34) | 1.11 (1.10 to 1.13) | 1.37 (1–34 to 1.40) | 1.08 (1.05 to 1.10) | 1.32 (1.25 to 1.39) | 1.00 (0.94 to 1.07) |
| Perineal laceration grades 3–4† | 1.31 (1.27 to 1.36) | 1.16 (1.12 to 1.20) | 1.29 (1.23 to 1.36) | 1.12 (1.05 to 1.18) | 1.10 (0.96 to 1.26) | 0.88 (0.75 to 1.02) |
| Preeclampsia | 0.95 (0.92 to 0.99) | 1.07 (1.03 to 1.12) | 1.18 (1.12 to 1.25) | 1.30 (1.22 to 1.39) | 1.60 (1.44 to 1.79) | 1.83 (1.62 to 2.06) |
| Abruptio placentae | 1.19 (1.09 to 1.30) | 1.27 (1.16 to 1.40) | 1.59 (1.42 to 1.78) | 1.71 (1.50 to 1.94) | 2.11 (1–70 to 2.63) | 2.09 (1.62 to 2.71) |
| Placenta praevia | 1.77 (1.58 to 1.99) | 1.74 (1.53 to 2.00) | 3.55 (3.11 to 4.06) | 3.47 (2.99 to 4.03) | 5.02 (4.00 to 6.29) | 5.23 (4.08 to 6.70) |
| PPH >1000 mL (VB) | 1.41 (1.37 to 1.45) | 1.27 (1.23 to 1.31) | 1.69 (1.62 to 1.76) | 1.47 (1.40 to 1.53) | 1.86 (1.69 to 2.05) | 1.48 (1.26 to 1.52) |
| PPH >1000 mL (CS) | 1.14 (1.01 to 1.28) | 1.04 (0.91 to 1.18) | 1.06 (0.91 to 1.24) | 0.95 (0.81 to 1.12) | 1.48 (1.17 to 1.88) | 1.35 (1.05 to 1.73) |
| Epidural analgesia† | 1.08 (1.06 to 1.09) | 1.03 (1.02 to 1.05) | 1.14 (1.12 to 1.17) | 1.06 (1.04 to 1.09) | 1.10 (1.04 to 1.15) | 0.98 (0.93 to 1.03) |
Reference group: maternal age 25–29 years.
*Adjusted for maternal body mass index and smoking habits at first antenatal care visit and year of birth. CS and preeclampsia also adjusted for gestational age.
†Forceps, vacuum extraction, epidural analgesia and perineal lacerations among vaginally delivered women.
‡ CS was subdivided into elective and acute CS from 1999.
aOR, adjusted OR; CS, caesarean section; GA, gestational age at delivery; PPH, postpartum haemorrhage; VB, vaginal birth.