Socioeconomic Position and Reproduction: Findings from the Australian Longitudinal Study on Women's Health.

Objective: To investigate the association of socioeconomic position (SEP) with reproductive outcomes among Australian women.

Methods: Data from the Australian Longitudinal Study on Women's Health's (population-based cohort study) 1973-1978 cohort were used (N = 6899, aged 37-42 years in 2015). The association of SEP (childhood and own, multiple indicators) with age at first birth, birth-to-pregnancy (BTP) intervals and total number of children was analysed using multinomial logistic regression.

Results: 14% of women had their first birth aged < 24 years. 29% of multiparous women had a BTP interval within the WHO recommendation (18-27 months). Women with a low SEP had increased odds of a first birth < 24 years: low (OR 7.0: 95% C.I. 5.3, 9.3) or intermediate education (OR 3.8: 2.8, 5.1); living in rural (OR 1.8: 1.5, 2.2) or remote (OR 2.1: 1.7, 2.7) areas; who found it sometimes (OR 1.8: 1.5, 2.2) or always difficult (OR 2.0: 1.6, 2.7) to manage on their income; and did not know their parent's education (OR 4.5: 3.2, 6.4). Low SEP was associated with having a much longer than recommended BTP interval.

Conclusion: As the first Australian study describing social differences in reproductive characteristics, these findings provide a base for reducing social inequalities in reproduction. Assisting adequate BTP spacing is important, particularly for women with existing elevated risks due to social disadvantage; including having a first birth < 24 years of age and a longer than recommended BTP interval. This includes reviewing services/access to postnatal support, free family planning/contraception clinics, and improved family policies.