Table 2 Sample description by cycle proficiency training status

Sex

Female (%)

52.0 (49.9–54.2)

56.2 (54.5–57.9)

0.003

Maternal education

Degree (%)

20.1 (18.4–21.8)

13.0 (11.8–14.2)

<0.0001

A level (%)

28.8 (26.9–30.8)

24.1 (22.6–25.6)

O level (%)

33.6 (31.5–35.6)

37.3 (35.6–39.0)

None/vocational (%)

17.5 (15.9–19.1)

25.7 (24.1–27.2)

Financial difficulties

Q1 (none) (%)

44.7 (42.5–46.8)

38.5 (36.8–40.3)

<0.0001

Q4 (%)

12.0 (10.6–13.4)

18.0 (16.6–19.3)

Highest parental occupational social class

I & II (%)

65.7 (63.6–67.7)

55.6 (53.8–57.3)

<0.0001

IIInm (%)

23.0 (21.2–24.9)

27.5 (25.9–29.1)

IIIm (%)

8.4 (7.2–9.6)

11.7 (10.5–12.9)

IV & V (%)

2.9 (2.2–3.7)

5.2 (4.4–6.1)

Housing tenure

Owned/mortgaged (%)

85.5 (84.0–87.0)

81.3 (80.0–82.7)

0.0001

Rent - private (%)

4.8 (3.9–5.7)

5.4 (4.6–6.2)

Rent - council (%)

6.9 (5.8–8.0)

10.5 (9.4–11.5)

Other (%)

2.9 (2.1–3.6)

2.9 (2.3–3.4)

Maternal smoking

Yes (%)

15.2 (13.7–16.7)

20.3 (18.9–21.7)

<0.0001

Parity

1+ (%)

50.5 (48.4–52.7)

54.2 (52.4–55.9)

0.009

Maternal age at delivery

<=23 yrs (%)

7.7 (6.6–8.9)

12.5 (36.3–39.7)

<0.0001

>23 to < =28 yrs (%)

35.3 (33.3–37.4)

38.0 (36.3–39.7)

>28 to < =33 yrs (%)

39.2 (37.1–41.3)

34.9 (33.3–36.6)

>33 yrs (%)

17.7 (16.1–19.3)

14.6 (13.4–15.8)

Older siblings at home

None (%)

49.2 (47.0–51.3)

45.9 (44.1–47.6)

0.018

1 (%)

36.5 (34.3–38.6)

37.1 (35.4–38.8)

2+ (%)

14.4 (12.8–15.9)

17.0 (15.6–18.4)

Resident dad

Biological (%)

84.4 (82.8–86.1)

77.1 (75.5–78.7)

<0.0001

Non-biological (%)

6.4 (5.3–7.6)

9.4 (8.3–10.5)

No (%)

9.1 (7.8–10.4)

13.5 (12.2–14.8)