This paper describe the case of pulmonary thromboembolism (PTE) in pregnancy diagnosed by angio CT. The clinical diagnosis of PTE in normal population is difficult. In pregnancy is even more complicated, because physiologic changes of pregnancy can mimic signs and symptoms of PTE. Our patient presented dyspnoea, breathing effort and cyanosis of the mouth at admission. In the check-up there was a distinct murmur just under the heart and tachycardia 115 bpm. The Doppler examination of the venous vessels of the lower extremities was normal. Echocardiography revealed features of right ventricular failure. Due to increased level of D-dimers and echocardiographic features of right-ventricular overload, the suspicion of pneumonic embolism was made. Therefore, in order to verify the initial diagnosis the decision of pulmonary CT angiography was made with the radiological protection of the fetus. This study revealed pulmonary embolism in the form of numerous defects in the contrast fillings of the pulmonary arteries. CT pulmonary angiography is the first imaging test of choice in general population who is suspected to have PTE. However, there is no consensus what should be preferred during pregnancy. In this paper the diagnostic concepts and an evidence-based guidelines were discussed in case of PTE in pregnancy as well as its side effects including teratogenicity and oncogenicity. In each case, the risks and benefits must be compared before a decision is taken. In case of thrombosis symptoms in the lower extremities, ultrasound should be taken as the next step, otherwise chest X-ray must be performed. In patients with normal chest X-ray, the next step should be scintigraphy, but if chest X-ray is abnormal, angio CT is preferred.