Despite an improvement in preventive care and perinatal health in previous decades, social inequalities persist, particularly to the disadvantage of isolated or unemployed women.

The objective was to analyse the evolution between 1998 and 2016 of the association between women's occupational status and perinatal outcomes.

Data came from four national surveys performed in 1998, 2003, 2010 and 2016. Occupational status was defined by maternal employment status and type of occupation during pregnancy. Preventive behaviours (initiation of antenatal care, antenatal classes, breast feeding) and health outcomes (hospitalization, preterm birth, birth weight below the 10th percentile) were analysed by occupational status adjusted for other maternal characteristics, for each study year.

The studied sample included 12,497 women in 1998, 13,290 in 2003, 13,209 in 2010 and 11,179 in 2016. The proportion of employed women increased from 66% to 75% between 1998 and 2016, and that of housewives decreased from 22% to 12%. The proportion of preterm births globally increased between 1998 and 2016, especially for housewives. The proportion of low birthweight for gestational age (LBWGA) remained similar over the years. From 1998 to 2016, the differences between occupational groups persisted for preterm births and LBWGA.

Occupational groups exhibited strong social differences in preventive care over the entire study period and persisted in the recent data. As a major social indicator, women's occupational status during pregnancy has to be considered as a risk factor of poor preventive behaviour and unfavourable perinatal outcomes.