To assess the association between sickness absence (SA) trajectories by medical diagnoses and exposure to occupational risk factors during pregnancy. Methods: SA trajectories were identified in a cohort of 367 pregnant workers from a healthcare institution (period 2010-2014), based on most frequent diagnosis using sequence analysis. Trajectory 1 included SA episodes due mainly to musculoskeletal disorders (58.86%), trajectory 2 included SA episodes due to pregnancy-related disorders (25.07%) and trajectory 3 included absences mainly covered by pregnancy-related occupational risk benefits (POR) and few SA episodes (16.08%). Exposure to occupational risk factors was assessed by experts and their association with trajectories was analysed using logistic regression. Relative risks (RR) and their 95% confidence intervals (95%CI) were adjusted for age, type of contract and work shift.Trajectory 1 was negatively associated with exposure to safety and ergonomic risks (RR=0.56, 95%CI=0.35-0.90; RR=0.50, 95%CI=0.33-0.77, respectively) and with the highest global risk index (RR=0.68, 95%CI=0.49-0.96). Trajectory 3 was associated with safety and ergonomic risks (RR=2.75, 95%CI=1.59-4.75; RR=3.64, 95%CI=2.18-6.06, respectively) and with the highest global risk index (RR=2.69, 95%CI=1.43-5.01). Nursing aides and nurses had a higher probability of belonging to trajectory 3 (RR 5.58, 95%CI=2.09-14.95 and RR 5.00, 95%CI 2.18-6.06, respectively).Pregnancy-related and musculoskeletal disorders are the most frequent sickness absence diagnosis during pregnancy. Low levels of occupational risk factors exposure were related to absences from work covered mainly by sickness absence. Current social benefits seem to be used as a complementary way to balance work and health during pregnancy.