Employment during pregnancy in relation to risk factors and pregnancy outcome

OBJECTIVE: To describe the relation of employment status during pregnancy to potential demographic, behavioural and obstetrical risk factors for adverse late pregnancy outcome, as well as the risks of having a preterm delivery and a small for gestational age infant. DESIGN: Cohort study. SETTING: A university hospital. SUBJECTS: Of 8,711 women with singleton pregnancies (1989-91), 5,875 returned questionnaires about risk factors and employment status at 16 and 30 weeks gestation. Of the respondents 5,552 were analysed in five groups: (1) women working throughout pregnancy, (2) women working in the first, but unemployed during the second trimester, (3) women on sick leave in the first and second trimester, (4) women unemployed throughout pregnancy, and (5) students. The association between employment status and having a small for gestational age infant and preterm delivery was evaluated, accounting for other risk factors. RESULTS: Working women and students had the most and unemployed women the least favourable demographic risk factors. Women on sick leave had the least favourable obstetrical and medical history, followed by unemployed women. No clear pattern of the behavioural risk factors was found. Differences in risk of having a small for gestational age infant were a function of parity, smoking and maternal height. Adjustment for these factors plus education yielded a lower risk of preterm delivery in partially unemployed women and higher risk among women on sick leave compared to working women, accounted for by different risks of bleeding in the second and third trimester. CONCLUSIONS: Comparison of pregnancy outcome among women with different work status should consider the differences in risk factor profile. Adjusting for such risk factors, we found no evidence that work per se had any detrimental or beneficial effects on the risk of having a small for gestational age infant or preterm delivery.