Table 2.

Baseline characteristics of women with linked perinatal data (NSW only, N = 1914) and the other women without linked data (ALSWH, N = 12333) from the Australian Longitudinal Study on Women’s Health 1973–78 cohort

	Included in the agreement study (NSW only)		Record not linked with PDC (the other women in the ALSWH cohort)
Characteristica
Age***	20.9 years		20.7 years
	n	%	N	%
Number of respondents at each survey***
1	1914	100.0	12333	100.0
2	1522	79.5	8166	66.2
3	1570	82.0	7511	60.9
4	1633	85.3	7512	60.9
5	1481	77.4	6719	54.5
6	1452	75.9	6558	53.2
Urban resident***	1105	57.7	6764	54.8
Partneredb***	526	27.6	2667	21.7
Difficulty managing on income	1005	52.5	6325	51.5
Education***
No formal education	41	2.2	367	3.0
School or higher school certificate	1274	66.8	8345	68.1
Trade or diploma	355	18.6	2208	18.0
University or higher university degree	237	12.4	1339	10.9
Parity**
None	1497	78.8	10062	82.2
One	253	13.3	1308	10.7
Two or more	137	7.2	813	6.7
Smoking Status*
Never Smoked	965	52.9	6158	52.2
History of Smoking	297	16.3	1788	15.2
Current Smoker	562	30.8	3859	32.7
Alcohol Intake Status
Non Drinker	164	8.7	1090	8.9
Rarely drinks/low risk drinker	1633	86.5	10419	85.4
Often drinks/high risk drinker	91	4.8	691	5.7

n number, PDC Perinatal Data Collection

*P-value is statistically significant at ≤0.05

**P-value is statistically significant at ≤0.01

***P-value is statistically significant at ≤0.001

^aParticipant characteristics were taken at baseline when the women were aged 18–23 years (ALSWH survey 1 (1996))

^bIncludes those women who are married or in a de facto relationship