In the western world, shift in values and attitudes towards partnership, reproduction and family (see Second Demographic Transition, Lesthaeghe & Van de Kaa, 1986), and shift from incidental to planned parenthood (Bajos & Ferrand, 2006 ; Knibiehler, 1997), contributed to reshape common reproductive ideals and make it easier to achieve them. New norms concerning quantum and timing of fertility substitute old ones in this new societal context (Liefbroer & Billari, 2010 ; Montgomery & Casterline, 1996). Two births per women (Prioux, 1994 ; Ajzen & Fishbein 1999), preferably accomplished around 30 years old (Moguérou et al., 2011 ; Liefbroer & Billari, 2010) is consider the normative reproductive behaviour. Less studied than for their fertility intensity, spatiality of women's timing fertility patterns at the local level acknowledges metropolitan specificity: aggregating both higher ‘early’ and 'late' fertility rates (see previous works).

This communication profiles women with timings considered 'deviant' with regards to moral and modal reproductive behaviour. It first presents factors cited in the literature for both 'early' and 'late' women childbearing with specific focus on their spatial scope ; from the state to the individual level. It then exposes the relevance of Belgian metropolitan areas as a study case via cross country age specific fertility mapping in north western Europe at different levels.
The empirical section uses Crossroads Bank for Social Security individual data on 15 to 49 year old women to expose the social determinants relevant in this context. Neighbourhood influence is partially validated without structural effect via multinomial regression. Hence, results suggest, for individual characteristics adjusted, some neighbourhood contexts do have an influence on fertility timing.

We conclude discussing individual strategies, locally differentiated spatial constraints (such as housing stock) and norms enhancing (and/or with weaker disapprobation of) reproductive behaviours elsewhere considered unconventional to explain this observed neighbourhood level aggregation.