Purpose <p>Shift work is a common occupational exposure that disrupts circadian rhythms which increases the risk of unhealthy behaviours and metabolic disorders. Maternal shift work is known to increase the risk of negative pregnancy outcomes, but the health impact when combining father’s shift work status remains uncertain. This study investigated the association between parental shift work before pregnancy and pregnancy outcomes, with a focus on the effect estimates of father’s shift work.</p> Methods <p>We analysed data from the Taiwan Birth Cohort Study, a prospective cohort of Taiwanese women who gave birth in 2005. We collected fathers' and mothers' shift work status before pregnancy and pregnancy outcomes [Caesarean section, excessive gestational weight gain (GWG), large or small for gestational age, low birth weight, nausea and vomiting, gestational hypertension, and gestational diabetes] from 13,221 families with term singletons. Multivariable linear models were used to analyse the associations between different maternal shift work statuses and pregnancy outcomes.</p> Results <p>Parental shift work before pregnancy was associated with higher odds of excessive GWG, Caesarean section, nausea and vomiting in the study population. Meanwhile, father’s shift work exposure was associated with higher odds of excessive GWG among mothers not doing shift work before pregnancy, but not among mothers doing shift work.</p> Conclusion <p>This study found that both mother’s and father’s shift work were associated with an increased risk of adverse pregnancy outcomes. Father’s shift work may be an unconsidered risk factor for adverse pregnancy outcomes, particularly in mothers without shift work exposure.</p>