Objective: To evaluate and validate the specificity of pulmonary ultrasound as a diagnostic tool for pleural effusion, pneumonia and pulmonary oedema in healthy pregnant women compared to non-pregnant healthy women. Design: Single-centre, prospective, observational controlled study. Setting: Large teaching hospital in the Netherlands. Population: All women underwent pulmonary ultrasound evaluation. We included 127 pregnant and 124 non pregnant women. Methods: Pulmonary ultrasound was performed in both pregnant and non-pregnant women. Presence and/of symptoms of pulmonary or cardiovascular pathology and ≤20 weeks of pregnancy were among the exclusion criteria. Pulmonary ultrasound was performed by following the BLUE-protocol. Main outcome measures: The following items were assessed: A-lines, B-lines, comet tails, pleural effusion, sub pleural consolidation and hepatization. Presence of three or more B-lines, pleural effusion and/or sub pleural consolidation was interpreted as a false positive outcome after review of an expert. Results: We included 251 patients, who underwent pulmonary ultrasound evaluation. None of the participants showed pleural effusion, sub pleural consolidation or hepatization. One participant showed presence of >3 B-lines. One ultrasound showed a spine sign. Thus, two of the pulmonary ultrasounds was considered false positive. Conclusions: In this study no differences in specificity of pulmonary ultrasound were found in healthy pregnant women compared to healthy non-pregnant women. This suggests translatability of pulmonary ultrasound studies to the pregnant population for the evaluation of respiratory complaints.