ObjectivesThe aim of this study was to determine the prevalence, the main features and the potential risk factors of LBP in pregnant women.MethodsThis cross‐sectional study included 173 pregnant women in the third trimester. Non‐inclusion criteria were severe mental disability and known previous history of musculoskeletal diseases. The participants were categorised into two groups: women with pregnancy‐related LBP and pain‐free women. Demographic, socio‐professional, clinical and obstetrical data were compared between the two groups using the appropriate statistical tests.ResultsThe mean age was 32.2 ± 5.4 years [17–45]. Among them, 108 (62.4%) reported one or more episodes of LBP during at least 7 days, mostly in the third semester (n = 71). The presence of LBP was significantly associated with history of LBP in previous pregnancies and jobs requiring prolonged standing. Active jobs and the presence of gestational complications were significantly more common in pain‐free women. In the multivariate analysis, LBP was independently predicted by the history of LBP in previous pregnancies and the absence of gestational complications.ConclusionsThe association of LBP with gestational complications as a protective factor has not yet been reported in previous studies. These complications are a common cause of hospitalisation, which represents a period of relative rest during pregnancy. Our results revealed that history of LBP in previous pregnancies, sedentary lifestyle prior to pregnancy and prolonged standing are the main risk factors of LBP. In contrast, rest and avoidance of physical overstrain during pregnancy may be protective factors.