AbstractObjectivesThe Tei Index (TI) is a useful, non‐invasive, Doppler‐derived myocardial performance tool which can be used to assess aspects of systolic and diastolic function. The aim of this study was to determine normal values of fetal left ventricular (LV) TI in second‐ and third‐ trimester fetuses and to compare these to other values reported in the literature.MethodsDoppler waveforms of the LV outflow tracts were obtained in 74 second‐ and early third‐trimester fetuses. The LV isovolumic contraction time (ICT), isovolumic relaxation time (IRT) and ejection time (ET) were measured and the TI calculated using the formula (ICT + IRT)/ET. The literature on LV myocardial function in the fetus was also reviewed.ResultsThe normal TI in second‐ and early third‐trimester fetuses (18–31 weeks' gestation) was 0.53 ± 0.13. The ICT was 43 ± 14 ms, the ET was 173 ± 16 ms and the IRT was 48 ± 13 ms.ConclusionThe TI can be easily obtained in the fetus without the need for precise anatomic imaging. The TI may be a useful tool to explore fetal myocardial function in different clinical situations. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.