Evaluation of fetal cardiac function in the first and second trimester by Tei index

Objective To measure Tei index of fetal heart in the first and early second trimester and its changes with gestation and assess its clinical value.Methods One hundred and sixty-five normal fetuses of 7-15 weeks gestation were scanned by transvaginal(≤12 weeks)or transabdonimal(12 weeks)ultrasound.The blood flow waveforms of the left ventricular outlet and inlet of every fetuses were imaged by pulse Doppler.The left ventricular isovolumic contraction time(ICT),isovolumic relaxation time(IRT)and ejection time(ET)were measured,then the Tei index was calculated by using the formula Tei index,and its changes with gestation age were analyzed.Results In the first trimester,Tei index decreased with gestation age and the most prominent was in 9 weeks gestation when the blood flow waveform became bi-wave('a' wave appeared).In the second trimester,the changes of Tei index seemed to have no relation with gestation age.Conclusion The fetal combined systolic and diastolic ventricular function is improved with gestation age in the first trimester and appeared little change in the second trimester.Tei index is quickly and easily obtained and reliable.It's a perfect index for assessing fetal cardiac function in the first and early second trimester.