Working hours and risk of gestational hypertension and pre-eclampsia.

BACKGROUND The potential impact of employment on maternal health, particularly in relation to gestational hypertension and pre-eclampsia, has been subject to research. However, there is limited evidence on associations between shift work and long working hours on the incidence of these conditions. AIMS To evaluate potential associations between maternal shift work and long working hours during pregnancy and gestational hypertension or pre-eclampsia. METHODS Multistage stratified systematic sampling was used to recruit 24 200 post-partum women from the Taiwan national birth registration database in 2005. Subjects underwent home interview 6 months after their deliveries by structured questionnaire to obtain characteristics of maternal employment and potential confounders. Diagnosis of gestational hypertension and pre-eclampsia was obtained from the birth registration. RESULTS There was no association between employment status and gestational hypertension or pre-eclampsia. Also, no significant association between gestational hypertension or pre-eclampsia and maternal shift work or long working hours during pregnancy was found in all or primiparous women. CONCLUSIONS There was no convincing evidence that maternal shift work or long working hours had a higher risk of gestational hypertension or pre-eclampsia. However, further research is warranted to confirm these negative findings.