Table 2.

Description of study population (women with at least one singleton live birth, n=4865)

	Na	%
Age at birth of first child
<=20	668	13.7
>20–25	1664	34.2
>25–30	1480	30.4
>30–35	747	15.4
>35	306	6.3
Social class at age 33
I	151	3.4
II	1187	26.6
III (manual/non-manual)	1864	41.8
IV	1015	22.8
V	242	5.4
Marital status at time of first pregnancy
married	3918	80.8
living with partner	452	9.3
single, divorced, widowed	479	9.9
Smoking at age 33
current	1554	33.1
former	855	18.2
never	2282	48.7
BMI at age 33
underweight	462	10.1
normal	2457	53.9
overweight	1112	24.4
obese	527	11.6
Parity through age 41
1	965	19.8
2	2493	51.2
3	1079	22.2
4	281	5.8
5	37	0.8
6	8	0.2
7	1	0.0
8	0	0.0
9+	1	0.0
interbirth interval (2nd–1st)
<2 years	1021	26.2
2–3 yrs	1254	32.2
>3 yrs	1616	41.5
Hardships experienced
Financial/structural hardship
0	3269	67.2
1	957	19.7
2+	639	13.1
No interest in education
0	2609	53.9
1	968	20
2+	1262	26.1
missing	26
Family dysfunction
0	3987	85.3
1+	689	14.7
missing	189
Lack of supportive caregiving
0	2879	62.6
1	1048	22.8
2+	670	14.6
missing	268
Violence/mental health issues
0	2765	56.8
1	1511	31.1
2+	589	12.1
Issues of family structure
0	3758	77.3
1	1107	22.8
Overall
0	1007	20.7
1	858	17.6
2	803	16.5
3	619	12.7
4+	1578	32.4

^anumbers may not add to total due to missing data