Table 1

Comparison of maternal and infant characteristics in the two cohorts of live very preterm births by gestational age group

Live births 24–31 weeks' gestational ageLive births 24–27 weeks' gestational ageLive births 28–31 weeks' gestational age
N=488N=580p ValueN=137N=159p ValueN=351N=421p Value
Population characteristics
Maternal age (mean (SD))30.1 (5.1)30.9 (6.0)0.0230.6 (5.6)30.6 (6.1)NS29.9 (5.5)31.0 (5.9)0.006
Multiple birth (%)32.627.60.0838.028.30.0530.527.3NS
Male (%)53.353.0NS48.249.7NS55.354.2NS
Birth weight (mean (SD))1203 (365)1170 (367)NS850 (171)844 (184)NS1338 (327)1292 (342)0.06
Gestational age (mean (SD))28.8 (2.0)28.7 (2.0)NS26.1 (0.9)25.9 (1.1)0.0829.9 (1.1)29.7 (1.1)0.03
Medical complications of pregnancy
Premature rupture of membranes/preterm labour (%)66.662.9NS81.878.6NS60.757NS
Haemorrhages (%)15.611.40.0411.710.1NS17.112.00.04
Hypertensive disease (%)24.223.6NS14.615.1NS27.926.8NS
Small for gestational age (%)32.935.5NS25.224.2NS35.939.8NS