Gramellini D, Chiaie D, Piantelli G, Sansebastiano L, Fieni S, Vadora E
Institute of Obstetrics and Gynaecology, University of Parma, Parma, Italy.
Ultrasound Obstet Gynecol. 2001 May;17(5):410-5. doi: 10.1046/j.1469-0705.2001.00264.x.
At present, most of the methods for sonographic assessment of amniotic fluid volume are unreliable in the second trimester of pregnancy, or else they do not present nomograms related to gestational age.
The aim of this prospective cross-sectional study was to construct normal reference ranges of four ultrasound parameters for the evaluation of amniotic fluid volume which could be applied in the second trimester. For these parameters we calculated normal curve limits suitable for use in clinical practice.
From a population of normal pregnant women between the 12th and the 24th weeks of gestation undergoing a routine ultrasound examination during 1997 at our institute, 273 were found to be suitable for the study, after the exclusion of all cases which presented any feto-maternal pathology or complications up to the 24th week.
The largest 'amniotic pocket' in a vertical direction, free of small fetal parts and umbilical cord, was measured: the maximum vertical and transverse diameters were measured on the same scan; the mean diameter and the product of the two diameters were calculated. The 'mean amniotic fluid diameter', the 'two-diameter pocket', the 'largest vertical pocket' and the 'largest transverse pocket' were the four sonographic parameters considered.
The four parameters correlated well with gestational week and with the biparietal diameter; the normal reference intervals and normal curve were then calculated. All these parameters were found to have good intra- and interoperative reproducibility.
We conclude that the use of an ultrasound semiquantitative method based on the measurement of a single amniotic fluid pocket and involving normal reference intervals according to gestational age could improve the early diagnosis of amniotic fluid variations during the second trimester, although this has yet to be confirmed by extensive clinical trials.
目前，大多数超声评估羊水量的方法在妊娠中期不可靠，或者没有给出与孕周相关的列线图。
这项前瞻性横断面研究的目的是构建可用于妊娠中期评估羊水量的四个超声参数的正常参考范围。对于这些参数，我们计算了适用于临床实践的正常曲线限值。
在1997年于我们研究所接受常规超声检查的12至24周妊娠的正常孕妇群体中，排除所有直至24周出现任何母胎病理或并发症的病例后，发现273例适合该研究。
测量垂直方向上最大的“羊水暗区”，避开胎儿小部分和脐带：在同一扫描上测量最大垂直和横径；计算平均直径和两个直径的乘积。“平均羊水直径”、“双径暗区”、“最大垂直暗区”和“最大横向暗区”是所考虑的四个超声参数。
这四个参数与孕周和双顶径相关性良好；然后计算正常参考区间和正常曲线。发现所有这些参数在术内和术间均具有良好的可重复性。
我们得出结论，使用基于测量单个羊水暗区并根据孕周设置正常参考区间的超声半定量方法，可改善妊娠中期羊水变化的早期诊断，尽管这还有待大规模临床试验证实。
