羊水量异常的超声诊断与胎儿畸形的关系

目的 探讨羊水量异常与胎儿畸形的关系.方法 回顾分析2004年3月至2006年11月在本院进行二维及三维超声检查34 900例20周以上的胎儿,其检出羊水量异常160例,并研究分析羊水量多少与胎儿畸形的关系.结果 160例羊水量异常中,羊水过多100例,羊水过少60例,二者畸形的发生率分别为37%、31.6%.结论 超声是诊断羊水量异常的首选方法,而且还能发现胎儿畸形,进一步证明羊水量异常与胎儿畸形的发生密切相关.     

Effect of fetal movement on the amniotic fluid index in diamniotic twin gestations

Fetal movement changes the size and location of amniotic fluid pockets during measurement of the amniotic fluid index. In singleton gestations, the effect of redistributing the fixed intrauterine fluid volume on the amniotic fluid index is clinically insignificant. In this study, we tested the hypothesis that the index in twin pregnancies is unaffected by fetal movement. A single examiner prospectively determined the amniotic fluid index before and after three discrete episodes of movement by both fetuses of 82 diamniotic twin pregnancies referred for obstetric sonograms between 20 and 38 weeks' menstrual age. A reliable blinded examiner provided a second post-movement measurement as a control. Data were analyzed by the paired t-test. The mean change in the amniotic fluid index after fetal movement was 2.1 ± 0.2 cm and 3.7 ± 0.3 cm for post-movement determinations by the same and blinded examiners, respectively (p < .001). Interobserver variation was 3.5 cm. Intraobserver variation was 1.8 cm for the first examiner and 2.2 cm for the second examiner. Therefore, interobserved and intraobserver variation can account for the observed change in the amniotic fluid index following movement of both diamniotic twins. © 1997 John Wiley & Sons, Inc. J Clin Ultrasound 25:255–257, 1997     

Association of amniotic fluid index with estimated fetal weight.

OBJECTIVE: The relationship between amniotic fluid volume and gestational age has been described previously. The association of body weight and urine output has been observed in human neonates. Our goal was to assess the correlation of the amniotic fluid index (AFI) with estimated fetal weight (EFW) in the third trimester. METHODS: We conducted a retrospective observational study on 426 pregnant women with singleton gestations who were referred to our unit for sonographic evaluation in the third trimester. The AFI, EFW, and EFW percentile corrected for gestational age were evaluated. The sonographic examinations were stratified into 3 gestational age categories: 28 through 33.9 weeks, 34 through 37.9 weeks, and 38 weeks and later. Maternal and fetal outcome variables were collected from medical records. Linear regression, Mann-Whitney U, and Kruskal-Wallis tests were used for statistical analysis. RESULTS: There was no significant relationship between the AFI and EFW in the entire group of patients (R = 0.08; P = .096). There was a significant relationship between the AFI and EFW after 38 weeks' gestation (R = 0.30; P = .003). In addition, in female fetuses the EFW percentile correlated with higher AFI values at all gestational ages (R = 0.31; P < .001); this, however, was not observed in male fetuses. CONCLUSIONS: There is no relationship between the AFI and EFW during the third trimester, although a positive relationship between the AFI and EFW was noted late in gestation. In pregnancies with female fetuses, the AFI was positively associated with EFW percentile before 38 weeks' gestation.     

Amniotic fluid and the clinical relevance of the sonographically estimated amniotic fluid volume: oligohydramnios

The amniotic fluid volume (AFV) is regulated by several systems, including the in-tramembranous pathway, fetal production (fetal urine and lung fluid) and uptake (fetal swallowing), and the balance of fluid movement via osmotic gradients. The normal AFV across gestation has not been clearly defined; consequently, abnormal volumes are also poorly defined. Actual AFVs can be measured by dye dilution techniques and directly measured at cesarean delivery; however, these techniques are time-consuming, are invasive, and require laboratory support, and direct measurement can only be done at cesarean delivery. As a result of these limitations, the AFV is estimated by the amniotic fluid index (AFI), the single deepest pocket, and subjective assessment of the AFV. Unfortunately, sonographic estimates of the AFV correlate poorly with dye-determined or directly measured amniotic fluid. The recent use of color Doppler sonography has not improved the diagnostic accuracy of sonographic estimates of the AFV but instead has led to overdiagnosis of oligohydramnios. The relationship between the fixed cutoffs of an AFI of 5 cm or less and a single deepest pocket of 2 cm or less for identifying adverse pregnancy outcomes is uncertain. The use of the single deepest pocket compared to the AFI to identify oligohydramnios in at-risk pregnancies seems to be a better choice because the use of the AFI leads to an increase in the diagnosis of oligohydramnios, resulting in more labor inductions and cesarean deliveries without any improvement in peripartum outcomes.     

正常足月产妇羊水组织因子水平与妊娠高凝状态、羊水栓塞的关系研究

目的探讨正常足月产妇羊水中的组织因子(TF)水平与妊娠高凝状态及羊水栓塞的关系。方法选取2013年1月至2014年12月该院待产的正常足月妊娠产妇158例,检测产妇血浆、羊水、羊水上清液及羊水沉渣中的TF和组织因子途径抑制物(TFPI)水平。结果羊水沉渣TF水平为(1 409.36±120.34)ng/L,明显高于血浆、羊水及羊水上清液水平,差异有统计学意义(P0.05);血浆TF水平为(30.17±6.49)ng/L,明显低于羊水各标本水平,差异有统计学意义(P0.05);羊水沉渣TFPI水平为(9.46±1.77)g/L,明显低于血浆、羊水及羊水上清液水平,差异有统计学意义(P0.05);血浆TFPI水平为(22.19±5.16)g/L,明显高于羊水各标本(P0.05);羊水及羊水上清液TF和TFPI水平差异无统计学意义(P0.05);羊水、羊水上清液、羊水沉渣中TF与TFPI呈负相关关系(P0.05),其中羊水沉渣相关性最强(r=-0.903,P0.05),血浆标本TF与TFPI无相关性(P0.05)。结论正常足月产妇羊水TF含量较高,而TFPI较低,可能在羊水栓塞的发生机制中起一定的临床作用。     

The fetal gastrointestinal tract is exposed to melatonin and superoxide dismutase rich amniotic fluid throughout prenatal development

Amniotic fluid (AF) is the first fluid to enter the gastrointestinal tract. Preterm birth is leading to a sudden interruption of AF swallowing. Understanding the composition of amniotic fluid is crucial to implement strategies preventing intestinal injury in preterm infants. We hypothesized that the fetal gastrointestinal tract (GIT) is exposed to melatonin and antioxidant enzymes via amniotic fluid throughout prenatal development. Amniotic fluid samples from 76 pregnant women with a median (range) gestational age of 38.0 (14.3–40.1) weeks have been collected. Immediately after birth blood samples were collected from the umbilical vein (n = 53). Median (Interquartile range) melatonin concentration was 30.5 pg/ml (12.7–118.3) and superoxide dismutase 1 (SOD1) concentration was 84 ng/ml (59–123). Extracellular glutathione peroxidase concentration was either not detectable or exceptionally low. We found a positive correlation between melatonin concentration in amniotic fluid and gestational age (Spearman’s correlation coefficient, r = 0.570, p<0.001), while SOD1 concentration in amniotic fluid was inversely correlated with gestational age (r = −0.246, p = 0.032). Compared to serum samples, melatonin concentration was statistically significantly higher in amniotic fluid (p<0.001). Our results indicate that the fetal gastrointestinal system is continuously exposed to melatonin and SOD1 via the amniotic fluid throughout prenatal development.     

Use of the amniotic fluid index combined with estimated fetal weight within 10 days of delivery for prediction of macrosomia at birth.

OBJECTIVE: The purpose of this study was to assess the value of combining the sonographically estimated fetal weight (EFW) and amniotic fluid index (AFI) measured within 10 days of term delivery for prediction of macrosomia at birth. METHODS: Prospective sonographic fetal biometric measurements and delivery ward data of a single center, uploaded separately over a 4-year period, were retrospectively linked to yield an unselected sample of nondiabetic pregnancies with live-born term neonates. RESULTS: Of the 1925 pregnancies evaluated, 140 (7.2%) were macrosomic (birth weight > or =4000 g). The AFI was significantly higher in the macrosomic group (P < .001). On receiver operating characteristic curve analysis, the area under the curve was larger for predictions based on the EFW alone than on the AFI. An EFW of 4000 g or higher had a positive predictive value of 46.6% for macrosomia at birth. Use of the previously suggested combined EFW and AFI cutoffs of 3689 g and 119 mm, respectively, yielded a positive predictive value of 30.3%. CONCLUSIONS: Combined use of the EFW and AFI rather than the EFW alone does not improve prediction of macrosomia at birth.     

The accuracy of ultrasound evaluation of amniotic fluid volume in singleton pregnancies: The effect of operator experience and ultrasound interpretative technique

The objective of this study was to evaluate the effect of operator experience and ultrasound interpretation technique on the accuracy of ultrasound estimates of amniotic fluid volume. Ultrasound evaluation was carried out by an obstetric resident, a nurse sonographer, a maternal-fetal medicine fellow, and a maternal-fetal medicine staff member to subjectively estimate (visual interpretation without sonographic measurements) amniotic fluid volume in 63 pregnancies. Amniotic fluid volume was also evaluated using ultrasound measurements based on the largest vertical pocket technique, the amniotic fluid index, and the two-diameter pocket method. The accuracy of these ultrasound estimates was assessed by comparing the ultrasound results to actual amniotic fluid volume as determined by a dye-dilution technique. For analysis, amniotic fluid volumes were classified as oligohydramnios, normal, or hydramnios using established volumetric criteria for singleton pregnancies. Subjective estimates ranged from 65% to 70% correct and did not differ by operator experience except for the more accurate diagnosis of hydramnios by the maternal-fetal medicine staff. The three sonographic measurements were similar in overall accuracy (59–67%). The two-diameter pocket method was, however, significantly more accurate in identifying oligohydramnios. It appears that neither operator experience nor sonographic technique greatly affects the accuracy of ultrasound estimates of amniotic fluid volume. © 1997 John Wiley & Sons, Inc. J Clin Ultrasound 25:249–253, 1997     

Prostate-specific antigen in amniotic fluid of normal and abnormal pregnancies

Objective: To examine if prostate-specific antigen (PSA) is present in amniotic fluid or maternal serum during pregnancy and if its presence is associated with fetal abnormalities.

Methods: Samples tested included amniotic fluids from 853 pregnant women for whom amniocentesis was performed; 312 nonpregnant women who donated blood; 259 pregnant women who donated blood at various gestational ages. Amniotic fluid or serum PSA was measured with an ultrasensitive time-resolved immunofluorometric procedure. 372 pregnancies were studied for the presence of genotypic or phenotypic fetal abnormalities.

Results: PSA was present in most amniotic fluids; the median PSA concentration increased from gestational week 11 to 22 and stabilized thereafter until delivery. The most prominent PSA concentration change occurred during gestational weeks 13–14. Pregnant women had significantly higher serum PSA concentrations than nonpregnant women; the pattern of serum fSA concentration change during pregnancy was similar to that of amniotic fluid; however, serum PSA concentrations were lower by a factor of 20–40. No association existed between amniotic fluid F'SA and maternal age, gender of fetus, or length of abstinence of mother from sexual intercourse. After gestational week 15, fetuses with trisomy 21 or 18, anencephaly, or renal disorders were associated with low amniotic fluid PSA levels.

Conclusion: Our data suggest that PSA may play a role in fetal development, especially at gestational ages between 13–20 weeks. The diagnostic usefulness of PSA in identifying fetal abnormalities remains to be determined.     

Maternal serum and amniotic fluid levels of human placental lactogen in gestational diabetes

Abstract. Human placental lactogen (hPL) levels were measured radioimmunologically in maternal serum and in amniotic fluid between the 37th and 39th weeks of gestation in sixteen gestational diabetic and thirty normal pregnant women. There was no significant difference in maternal serum hPL levels between diabetic (6.1 μ g/ml) and normal pregnant women (6.4 μ g/ml). In contrast, the diabetic group was found to have significantly ( P< 0.001) higher concentrations of amniotic fluid hPL (1.2 μ g/ml) than normal pregnant women (0.8 μ g/ml).     

Maternal serums and amniotic fluid levels of human placental lactogen in gestational diabetes.

Human placental lactogen (hPL) levels were measured radioimmunologically in maternal serum and in amniotic fluid between the 37th and 39th weeks of gestation in sixteen gestational diabetic and thirty normal pregnant women. There was no significant difference in maternal serum hPL levels between diabetic (6.1 microgram/ml) and normal pregnant women (6.4 microgram/ml). In contrast, the diabetic group was found to have significantly (P less than 0.001) higher concentrations of amniotic fluid hPL (1.2 microgram/ml) than normal pregnant women (0.8 microgram/ml).     

PCR-SSP技术对羊水细胞ABO血型的基因鉴定

目的通过PCR-SSP基因技术检测胎儿羊水细胞ABO血型基因型,产前诊断胎儿ABO血型。方法选取了6名孕16 W以上的孕妇,抽取羊水细胞并进行分离,提取羊水细胞DNA,运用PCR-SSP技术分析其ABO血型基因型,并通过出生后的脐带血的血型鉴定进行确认。结果 6例羊水标本均通过PCR-SSP方法检测出了ABO血型的基因型;该6名胎儿的脐带血的ABO血型与羊水细胞的血型一致。结论 PCR-SSP技术可以准确地检测胎儿羊水细胞的ABO血型。     

Polymerase chain reaction in the detection of microbes in amniotic fluid

Intra-amniotic infection during pregnancy can be caused by bacteria, viruses or protozoa, Toxoplasma gondii for example. Bacterial intrauterine infections are connected with premature birth, premature rupture of fetal membranes, and infective complications of both the mother and the newborn. Viral infections and Toxoplasma gondii can cause fetal malformations and illness with serious sequelae to the infant or fetal death in utero. Determining the causative agent is important and often greatly affects the prognosis of the newborn. Amniotic fluid is in most cases easily and safely obtainable during the second and third trimester and can be used in several microbiological assays. These include bacterial and viral cultures, Gram staining, quantitative assays for immunoglobulins or cytokines, and polymerase chain reaction (PCR) for detecting microbial DNA. This review concentrates on broad-spectrum or universal bacterial PCR for detection of bacterial DNA in amniotic fluid and on PCR assays for certain clinically important viruses and for Toxoplasma gondii.     

The effects of maternal position on the amniotic fluid index.

OBJECTIVE: We investigated the influence of maternal positioning on the measurement of the amniotic fluid index (AFI) in third-trimester pregnancies. We wanted to determine whether a change in the position of the women, from supine-flat to supine-elevated, would influence the measurement of the AFI. METHODS: Each patient had AFI measurements obtained in both positions by the same investigator. RESULTS: We determined the values of the amniotic fluid index to be consistent in both positions for pregnancies with normal AFI measurements. CONCLUSIONS: Measurements of the amniotic fluid did not appear to be influenced by maternal position in the third trimester when the AFI was in the normal range.     

Three-dimensional sonographic volume measurement of the fetal cerebellum

Purpose The objective of this longitudinal study was to evaluate the growth of the fetal cerebellum in normal pregnancy by using three-dimensional ultrasound. Methods Three-dimensional sonographic examinations were performed for 13 appropriate-for-gestational-age fetuses. Fetal cerebellar volume was measured every 2 to 3 weeks after 20 weeks of gestational age until delivery. The common multiplanar technique was used to calculate the fetal cerebellar volume. Results A curvilinear relationship was found between gestational age and cerebellar volume (R² = 78.6%, P < 0.0001), and normal ranges of cerebellar volume measurements for estimating the growth of the fetal cerebellum during normal pregnancy were generated. The data gathered in this study were fairly comparable with previous data obtained using three-dimensional ultrasound. However, the normal ranges of cerebellar volume that we determined were relatively wide throughout pregnancy. Conclusions Our findings suggest that a standard curve for fetal cerebellar volume using three-dimensional ultrasound can play a role in the evaluation of normal cerebellar growth in the fetus. However, we do cast doubt on the reliability and reproducibility of cerebellar volume measurement using three-dimensional ultrasound. Further studies involving a larger sample size and another technique (the rotational method with VOCAL) would be needed to confirm these findings.     

Catalytic ferrous iron in amniotic fluid as a predictive marker of human maternal-fetal disorders

Amniotic fluid contains numerous biomolecules derived from fetus and mother, thus providing precious information on pregnancy. Here, we evaluated oxidative stress of human amniotic fluid and measured the concentration of catalytic Fe(II). Amniotic fluid samples were collected with consent from a total of 89 subjects in Nagoya University Hospital, under necessary medical interventions: normal pregnancy at term, normal pregnancy at the 2nd trimester, preterm delivery with maternal disorders but without fetal disorders, congenital diaphragmatic hernia, fetal growth restriction, pregnancy-induced hypertension, gestational diabetes mellitus, Down syndrome and trisomy 18. Catalytic Fe(II) and oxidative stress markers (8-hydroxy-2''-deoxyguanosine, 8-OHdG; dityrosine) were determined with RhoNox-1 and specific antibodies, respectively, using plate assays. Levels of 8-OHdG and dityrosine were higher in the 3rd trimester compared with the 2nd trimester in normal subjects, and the abnormal groups generally showed lower levels than the controls, thus suggesting that they represent fetal metabolic activities. In contrast, catalytic Fe(II) was higher in the 2nd trimester than the 3rd trimester in the normal subjects, and overall the abnormal groups showed higher levels than the controls, suggesting that high catalytic Fe(II) at late gestation reflects fetal pathologic alterations. Notably, products of H₂O₂ and catalytic Fe(II) remained almost constant in amniotic fluid.     

Three-dimensional sonographic measurement of fetal renal volume

Objective The objective of this longitudinal study was to evaluate the growth of the fetal kidney in normal pregnancies using three-dimensional ultrasound. Methods Three-dimensional sonographic examinations were performed on 13 appropriate-for-gestational-age fetuses. Fetal renal volume was measured every 2 to 3 weeks after 20 weeks gestational age until delivery. Results There was a good linear correlation between left and right renal volumes (r = 0.9614, P < 0.0001). Curvilinear relationships were found between gestational age and left and right renal volume (left: R² = 79.1%, P < 0.0001; right: R² = 74.2%, P < 0.0001), and normal ranges of left and right renal volume measurements for estimating the growth of the fetal kidney during normal pregnancy were generated. There was a difference for each predicted value of the fetal renal volume in the third trimester of pregnancy in our study and in two other previous studies. The left and right fetal renal volume to estimated fetal weight ratios were constant during the pregnancies studied. Conclusion Our findings suggest that fetal renal volume measurement plays a role in assessment of the growth of fetal kidneys. However, we are doubtful about the reproducibility of fetal renal volume measurements made by using three-dimensional ultrasound in utero. Further studies involving larger sample sizes are needed to reevaluate the usefulness and reproducibility of fetal renal volume measurements.