AbstractObjectiveTo compare fetal Tei index before, immediately after and 30 min after cordocentesis for prenatal diagnosis.Patients and methodsPregnant women undergoing prenatal diagnostic cordocentesis in the early mid‐trimester underwent measurement of the fetal Tei index of both right and left ventricles just before cordocentesis, immediately after and at 30 min after the procedure.ResultsA total of 143 singleton women underwent cordocentesis at a median gestational age of 19 weeks (range 16–23). The most common indication was fetal risk of beta‐thalassemia/hemoglobin E disease (42%, 60 cases). Immediately after cordocentesis, fetal Tei index and all its components at both ventricles were significantly altered when compared with the baseline values (p < 0.001). At 30 min after cordocentesis, components of the Tei index had significantly improved but 5/6 had not completely recovered. No serious procedure‐related short‐term complications were observed in the study.ConclusionCordocentesis has a negative impact on fetal hemodynamics as indicated by worsening of the Tei index. Although the adverse effect seems to be temporary, the recovery time may be longer than 30 min. © 2016 John Wiley & Sons, Ltd.