Premature labour has been treated with Fenoterol and Verapamil since 1970 in the Working Team of Perinatal Medicine of Berlin Free University/Municipal Gynaecological Clinic at Berlin-Neukölln. Elective necroses of the myocardial fibres after stimulation with high concentrations of beta 2-sympathicomimetics have been demonstrated in animal experiments and in isolated foetal myocardial preparations in vitro. It is claimed that such lesions can be avoided by the additional administration of Ca2+ antagonists. Fenoterol and Verapamil will pass the placental barrier. In order to clarify whether long-term tocolysis may exercise an effect on the foetal myocardium, the authors examined 140 children. 78 children of mothers treated with long-term tocolysis were compared with 62 children of mothers who had not received such treatment. The systolic time intervals were measured in full-term children born between 1970 and 1974 and aged 6 to 10 years. Following recording of the case history and physical examination, the ECG, phonocardiogram as well as the carotid sphygmogram were recorded. The frequency rate of abnormal ECG findings (RVL, AV block of the first degree, WPW syndrome) in the tocolysis groups did not differ from that of the untreated control group. Besides, the myocardial contractilities of both groups were also not different from each other.