Table 2

Obstetric and neonatal outcome characteristics of primiparous women with singleton births in the period 1992–2010

CharacteristicsAge groups
<17 years (n=2392)17–19 years (n=29 816)20–24 years (n=185 942)25–29 years (n=300 822)30–34 years (n=205 905)35–39 years (n=63 163)40+ years (n=10 634)
Labour
 Spontaneous onset labour205585.9%25 85386.7%158 87985.4%251 34083.6%163 87679.6%45 33071.2%626158.9%
 Induced labour1847.7%25288.5%17 4339.4%30 87310.3%25 47412.4%10 06515.9%211119.9%
Mode of delivery
 Normal vaginal birth203084.9%25 09684.2%147 08279.1%219 99373.1%135 09965.6%35 11255.6%472444.4%
 Forceps70.3%1260.4%11430.6%21660.7%15150.7%5750.9%840.8%
 Vacuum extraction1436.0%20907.0%18 0119.7%36 69612.2%29 81114.5%10 11916.0%159915.0%
 CS*2138.9%25008.4%19 74710.6%42 04414.0%39 53419.2%17 35527.5%422639.7%
 CS elective 1999–2010†532.2%3731.3%28281.5%69732.3%76563.7%38536.1%113210.6%
 CS acute 1999–2010†733.1%8823.0%70923.8%16 6515.5%17 9538.7%782612.4%179816.9%
Gestational age (weeks)
 GA <28200.8%1070.4%4640.2%7430.2%6400.3%2920.5%730.7%
 GA <32401.7%3081.0%14360.8%24150.8%20481.0%9001.4%2061.9%
 GA <372138.9%19376.5%11 0305.9%18 0055.6%12 7276.2%45867.3%8778.2%
 GA 37–41199083.2%25 81186.6%161 04386.6%257 32085.5%172 62183.8%51 49481.5%878682.6%
 GA ≥421656.9%19676.6%13 6277.3%25 2788.4%20 3719.9%701811.1%9579.0%
Maternal complications and use of epidural analgesia
 Perineal laceration grades 1–2‡31114.3%398214.6%32 60219.6%70 45227.3%55 16333.2%15 47733.9%211633.1%
 Perineal laceration grades 3–4‡231.1%2721.0%30301.8%82023.2%68464.1%18564.1%2223.5%
 Preeclampsia431.8%5761.9%43172.3%65202.2%42652.1%16102.5%3653.4%
 Abruptio placentae160.7%1350.5%6430.3%11710.4%9550.5%3900.6%870.8%
 Placenta previa20.1%160.1%1590.1%5050.2%6120.3%3750.6%890.8%
 PPH >1000 mL (VB)653.0%6672.4%50783.1%10 9314.2%97205.9%31736.9%4857.6%
 PPH >1000 mL (CS)20.9%281.1%2521.3%5411.3%5781.5%2371.4%801.9%
 Epidural analgesia‡90341.4%11 56942.4%68 33241.1%105 26640.7%70 69142.5%20 15144.0%274342.9%
Neonatal
 Fetal distress80.3%1220.4%9320.5%16210.5%10700.5%3880.6%560.5%
 Fetal distress80.3%1220.4%9320.5%16210.5%10700.5%3880.6%560.5%
 Aspiration of meconium00%300.1%3630.2%6490.2%5630.3%1930.3%420.4%
 Shoulder dystocia60.3%780.3%7930.4%15800.5%13820.7%4890.8%790.7%
 Stillbirth70.3%1020.3%5710.3%8930.3%7680.4%3470.5%870.8%
 SGA913.8%11363.8%60163.2%88312.9%72163.5%29624.7%6175.8%
 LGA472.0%5391.8%38382.1%59432.0%38461.9%12792.0%2242.1%
 Apgar score <7 at 5 min431.8%3811.3%24091.3%41581.4%33541.6%12742.0%2402.3%
 Birth weight (g)3348592340356534535543470555345257234156123360640
  • Figures denote counts and proportions or mean and 1 SD.

  • *All CS independent of status of performance—acute or elective.

  • †CS was subdivided into elective and acute CS from 1999.

  • ‡Epidural analgesia and perineal lacerations in vaginal births only.

  • CS, caesarean section; GA, gestational age at birth; LGA, large-for-gestational age; PPH, postpartum haemorrhage; SGA, small-for-gestational age; VB, vaginal birth.