Group

Maternal age mean

Parity median

Gestation (no. of weeks)

mean^* (range)

Idiopathic—case

30

0

33 (30 - 34)

Idiopathic—control

29

0

33 (30 - 35)

Chorioamnionitis—case

31

0

28 (23 - 34)

Chorioamnionitis—control

31

0

28 (23 - 34)

Ischaemic—case

29

0

31 (28 - 32)

Ischaemic—control

27

0

31 (28 - 32)