The sensitivity was 0.82 the specificity 0.98, with a high kappa of 0.82. The result was a fairly good predictive value, which was not possible by other methods. (1987) conducted a Doppler study on 52 twin pregnancies and four sets of triplets designed to diagnose discordant growth in twins as early as possible. Doppler ultrasound was considered to be a very promising addition to the armamentarium.
The sensitivity was 0.50 the specificity 0.89. In summary, their results showed that some individual readings as well as the indices, especially flow volume, were of almost identical value in predicting an unfavorable outcome of the pregnancy. They also determined flow volumes in the aorta. and the descending aorta together with the pulsatility index (PI). They determined the S/D ratio in the umbilical aa. published a study designed to find indicators for an unfavorable course for a pregnancy. In these cases they did not see this as a sign of preplacental pathology, as might be assumed in single pregnancies with growth restriction and abnormal Doppler findings in the maternal uterine aa. They were able to show that when Doppler findings in a twin were abnormal and growth was restricted this was accompanied by selective placental pathology. (1993) investigated whether factors interfering with growth were preplacental or placental. By contrast, the early results from studies linking discordant growth with presumed TTTS were rather anecdotal in nature. The sensitivity was 0.79 the specificity 1. Abnormal elevation of the S/D ratio identified growth-restricted fetuses in 26 out of 33 cases, while normal values were found in all 32 pregnancies in which the infants were of normal size. They examined the S/D ratio (the ratio between the systolic maximum and the diastolic minimum of the waveform) in the umbilical aa. published the first larger study of the use of Doppler ultrasound in 76 multiple pregnancies. However, diagnostic studies of the fetal membranes to determine chorionicity for the assessment of risk, which have been especially valuable lately, were not yet as developed when those studies appeared. Selective display of hemodynamic parameters was especially well accepted, since, as mentioned earlier, the simpler methods for assessing risk in single pregnancies are often ineffective in multiple pregnancies.Ĭonsequently, some studies were undertaken as early as the 1980s using Doppler ultrasound examinations for screening, but also to evaluate previously established risks. Monitoring multiple pregnancies by Doppler ultrasound was considered promising from a relatively early stage. Studies Using Doppler Ultrasound for Multiple Pregnancies 2 Display of a monoamniotic twin pregnancy. The reasons for this will be clear by the end of this chapter.įig. In the author’s opinion every twin pregnancy, but especially every monochorionic twin pregnancy, should in itself be an indication for Doppler ultrasound examination. Discordant growth is a specific indication during this time, beside the indications arising during singleton pregnancies. This chapter will only briefly refer to the special morphological and functional problems of conjoined twins.ĭoppler ultrasound is part of the risk assessment in the second half of pregnancy. In monochorionic multiple pregnancies additional problems arise with communications between the fetal circulations such as a twin-to-twin transfusion syndrome (TTTS), (feto–fetal transfusion syndrome ) or twin reversed arterial perfusion (TRAP).
1) constrictions in nutritional supply are the primary problem because they may result in discordant or restricted growth. In the case of dichorionic multiple fetuses ( Fig. The more closely the multiple fetuses are linked, the more important becomes the use of biophysical methods. For this reason ultrasound techniques such as cardioto-cogram (CTG), ultrasound, Doppler ultrasound, and color Doppler ultrasound are indispensable aids when multiple pregnancies are being monitored. Simple monitoring methods used successfully for single fetuses, such as inspection, palpation, fundal height, abdominal girth, etc., fail to provide information about an individual infant in a multiple pregnancy. Multiple pregnancies are one of the indications for Doppler ultrasound in obstetrics that are included in many guidelines, especially when there is discordant growth of the infants.
Multiple Pregnancy and Doppler Ultrasound