| Objectives1.To discuss the relationship between nuchal translucency(NT)thickness and fetal structural abnormalities in the first-trimester.2.To discuss the relationship between increased NT,tricuspid regurgitation,abnormal ductus venosus waveform and congenital cardiovascular abnormalities.3.To analyze the correlation between increased NT and fetal cardiovascular abnormalities.MethodsIn the first-trimester(11?13+6 weeks),single pregnant womenwere examined by ultrasound to measure NT thickness and scan the fetal structure According to the thickness of NT,the cases were divided into the normal NT group(NT thickness<3.5 mm)and increased NT group(NT thickness>3.5 mm).Fatal abnormalities were recommended to terminate pregnancy,while non-fatal abnormalities would terminate or continue pregnancy according to the wishes of parents.Those confirmed with non-fatal abnormalities still willing to continue pregnancy and those who do not find structural abnormalities,ultrasound examination shall be repeated in the second and third trimesters,and prenatal diagnosis shall be made if necessary.Those who continue pregnancy were followed up till the 6th month after delivery.Termination of pregnancy shall be confirmed by pathological anatomy or the last prenatal ultrasound examination,and infants shall be confirmed by postnatal examinations.The number of different pregnancy outcomes were recorded in normal NT group and increased NT group.Maternal age,the incidences and location of fetal structural abnormalities were compared between two groups.Increased NT group was redivided into 3.5?4.4 mm subgroup,4.5?5.4 mm subgroup,5.5?6.4 mm subgroup,and ?6.5 mm subgroup.The incidences of fetal structural abnormalities were compared among these subgroups.To compare the difference of maternal age in cardiovascular abnormalities group and normal cardiovascular system group.Calculate the sensitivity,specificity,positive predictive value,negative predictive value,positive likelihood ratio and negative likelihood ratio of increased NT,tricuspid regurgitation,and abnormal ductus venosus waveform screening for cardiovascular abnormalities when they exist in isolation and in combination.The detailed classification of cardiovascular abnormalities in normal NT group and increased NT group was recorded,and the incidences of malformation types in the two groups were compared.ResultsA total of 6 399 fetuses were included in the study,5 925 in normal NT group and 474 in increased NT group.There were 10 cases of abortion,107 cases of induction of labor,11 cases of premature labor and 5 797 cases of term labor in normal NT group.And there were 6 cases of abortion,192 cases of induction of labor,3 cases of premature delivery and 273 cases of term labor in increased NT group.Maternal age of increased NT group was younger than normal NT group(P<0.05).The incidence of structural abnormalities in increased NT group(26.58%)was higher than normal NT group(2.43%)(P<0.05).The incidence of cardiovascular abnormalities in increased NT group(57.94%)was higher than normal NT group(18.75%)(P<0.05).The incidence of central neural system abnormalities and abdominal organs abnormalities in increased NT group(12.70%and 9.52%,respectively)was lower than normal NT group(32.64%and 22.92%,respectively)(P<0.05).The incidence of structural abnormalities in the>6.5 mm subgroup(42.97%)was higher than that in the 4.5?5.4 mm subgroup(23.40%)and 3.5?4.4 mm subgroup(15.23%)(P<0.05).The incidence of structural abnormalities the 5.5?6.4 mm subgroup(34.55%)was higher than that in the 3.5?4.4 mm subgroup(15.23%)(P<0.05).The incidence of structural abnormalities was no significant difference between 3.5?4.4 mm subgroup and 4.5?5.4 mm subgroup,4.5?5.4 mm subgroup and 5.5?6.4 mm subgroup,5.5?6.4 mm subgroup and?6.5 mm subgroup(P>0.05).There was no significant difference in maternal age between cardiovascular abnormalities group and normal cardiovascular system group(P>0.05).The sensitivity and negative predictive value of isolated increased NT in screening cardiovascular abnormalities were higher than that of tricuspid regurgitation and abnormal ductus venosus waveform(P<0.05).The specificity of isolated tricuspid regurgitation in screening cardiovascular abnormalities was higher than increased NT and abnormal ductus venosus waveform(P<0.05).There was no significant difference in the positive predictive value of isolated increased NT,tricuspid regurgitation and abnormal ductus venosus waveform in screening cardiovascular abnormalities(P>0.05).The sensitivity of increased NT with abnormal ductus venosus waveform in screening cardiovascular abnormalities was higher than that of isolated tricuspid regurgitation and abnormal ductus venosus waveform(P<0.05).The specificity of increased NT with tricuspid regurgitation,increased NT with tricuspid regurgitation and abnormal ductus venosus waveform in screening cardiovascular abnormalities was higher than that of isolated increased NT,tricuspid regurgitation and abnormal ductus venosus waveform(P<0.05).The positive predictive value of increased NT with abnormal ductus venosus waveform,increased NT with tricuspid regurgitation and abnormal ductus venosus waveform was higher than that of isolated increased NT,tricuspid regurgitation and abnormal ductus venosus waveform(P<0.05).The negative predictive value of increased NT with tricuspid regurgitation,increased NT with abnormal ductus venosus waveform,increased NT with tricuspid regurgitation and abnormal ductus venosus waveform was lower than that of isolated increased NT(P<0.05).The positive likelihood ratio of isolated increased NT,tricuspid regurgitation and abnormal ductus venosus waveform were 9.34,4.50 and 9.80 respectively,while the negative likelihood ratio were 0.55,0.98 and 0.89 respectively.The positive likelihood ratio of increased NT with tricuspid regurgitation and abnormal ductus venosus waveform was the highest.While the negative likelihood ratio had no significant change.There was no significant difference between increased NT group and normal NT group in various types of cardiovascular abnormalities(P>0.05).Conclusion1.The incidence of structural abnormalities in fetuses with increased NT during first-trimester was signific antly higher.And the incidence of structural abnormalities was increased with NT thickness.The most common of which was cardiovascular abnormalities.2.The incidence of cardiovascular abnormalities in increased NT group was higher than normal NT group.While the incidence of central neural system abnormalities and abdominal organs abnormalities in increased NT group were lower than normal NT group.3.When the fetuses had increased NT,it is necessary to assess blood flow across the tricuspid valve and in the ductus venosus.If tricuspid regurgitation and/or abnormal ductus venosus wave form were found in fetuses with increased NT,especially when all three were detected,fetal echocardiography examination should be recommended in the early second trimester.4.At present,the research results could not show that increased NT could provide evidence for classification of cardiovascular abnormalities. |
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