Non protein bound iron concentrations in amniotic fluid

OBJECTIVES: To investigate whether amniotic fluid concentrations of non protein bound iron (NPBI) vary with growth in healthy fetuses and also offer a reference curve in the second trimester of pregnancy. DESIGN AND METHODS: Amniotic fluid concentrations of NPBI were measured by HPLC in 118 women with physiological singleton pregnancies, who underwent amniocentesis for fetal karyotype between weeks 15 and 18 of gestation. RESULTS: NPBI increased progressively from weeks 14--15 to weeks 15--16, peaking at 17--18 weeks of gestation. NPBI values regressed positively with gestational age (GA). Multiple linear regression analysis between NPBI, as dependent variable, and various fetal parameters, as independent variables, showed a statistically significant regression coefficient with GA, bi-parietal diameter and transverse cerebellar diameter. CONCLUSIONS: The present data constitutes the first quantification of NPBI concentrations in amniotic fluid under physiological conditions. Correlations with GA and ultrasound fetal biometry suggest that NPBI may play a role in fetal growth.     

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     

Correlation between fetal gastric size and amniotic fluid volume

PURPOSE: Since abnormal conditions of the fetal digestive tract may alter both amniotic fluid volume and fetal gastric volume, we sought to determine whether amniotic fluid volume is correlated with fetal gastric volume in normal pregnancy. METHODS: A total of 280 fetal gastric size measurements were made prospectively from routine sonographic examinations of women with normal singleton pregnancies between 16 and 42 weeks of gestation. The fetal stomach was defined as the largest area including the pyloric site on transverse or oblique real-time sonographic scans. Gastric volume was calculated according to the formula for a prolate ellipsoid. The amniotic fluid index (AFI) was used for the evaluation of amniotic fluid volume. RESULTS: Both fetal gastric volume and AFI were significantly correlated with gestational age (R2= 0.422 and R2= 0.128, respectively). Only a weak correlation was found between gastric volume and AFI (R2= 0.036, p <0.001). On multivariate linear regression analysis adjusting for gestational age and fetal biometric measurements, gastric volume was not an independent and significant predictor of AFI. CONCLUSIONS: Although sonographically determined fetal gastric volume measurements appear to be useful in the assessment of fetal digestive tract anomalies, fetal gastric volume has no clinically significant effect on the amniotic fluid volume in normal pregnancy.     

Amniotic fluid alpha-fetoprotein determination at the time of genetic amniocentesis: has it outlived its usefulness?

The purpose of this retrospective study was to evaluate the utility of routine measurement of amniotic fluid alpha-fetoprotein levels at the time of second trimester genetic amniocentesis (mean gestational age, 17.3 weeks +/- 2.5 weeks standard deviation; median, 16.8 weeks; range, 15 to 22 weeks). During the study period 7174 patients underwent second trimester genetic amniocentesis. Outcome data were available in all cases. In 79 (1.1%) cases the amniotic fluid alpha-fetoprotein level was > or = 2.0 multiples of the median. Thirty-three of the 79 (42%) patients had normal ultrasonograms, and in 31 of 33 (94%) the amniotic fluid alpha-fetoprotein level was between 2.0 and 3.0 multiples of the median. Forty-six of the 79 (58%) patients had abnormal ultrasonographic findings, and of these, 82% were neural tube defects, abdominal wall defects, or cystic hygromas. Acetylcholinesterase was positive in 37 cases, all of which had abnormal ultrasonographic findings. None of the fetuses with negative findings on sonographic screening had detectable abnormalities at birth. In this study, with over 7000 patients, amniotic fluid alpha-fetoprotein and acetylcholinesterase levels did not increase the detection of fetal abnormalities. On the basis of these results, routine measurement of amniotic fluid alpha-fetoprotein level at the time of routine genetic amniocentesis (15 to 22 weeks) does not appear justified.     

The 'Mickey Mouse' sign and the diagnosis of anencephaly in early pregnancy.

OBJECTIVES: To assess the sonographic screening for anencephaly in the first trimester in a low-risk obstetric population. METHODS: Since 1994, 5388 women attended our clinic for a first-trimester scan (11-14 weeks of gestation) and screening for structural and chromosomal abnormalities. The patients underwent transabdominal scanning, and transvaginal scanning if necessary. RESULTS: The ultrasonographic appearances of anencephaly in the first trimester are different from the familiar second-trimester signs. The cerebral hemispheres are present and exposed to the surrounding amniotic fluid. The ultrasound appearances in the coronal section of the head are best described as 'Mickey Mouse face'. There were six cases of anencephaly (incidence 1.1:1000). All cases were diagnosed in the first trimester and five demonstrated this sign. There were no false-positive diagnoses. The crown-rump length was significantly reduced in all affected fetuses. CONCLUSION: First-trimester ultrasonographic diagnosis of anencephaly is accurate, but sonographers should be familiar with the ultrasound appearances that are different from those in the second trimester.     

Transvaginal sonography (TVS) of the fetal urinary tract

Examination of the fetal urinary tract is an integral part of routine sonographic examination in the second trimester of pregnancy. Malformations of the urinary tract are being detected at an ever-increasing rate, mostly because they are associated with two easily visualized sonographic markers: the cystic accumulation of fluid and a change of the amniotic fluid volume. Detailed evaluation of the fetal urinary tract and identification of anomalies were considered to be difficult before the 18th week from the last menstrual period (LMP) before the use of transvaginal sonography (TVS). Transvaginal sonography (TVS), owing to its proximity to the maternal pelvic organs at early gestation, enables earlier determination of both normal and abnormal findings in the fetal urinary system such as: renal agenesis, polycystic and multicystic kidneys, hydronephrosis, and bladder extrophy. The TVS enables earlier and more accurate diagnosis and identification of fetal urinary tract anomalies as compared with abdominal ultrasound.     

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.     

Umbilical cord cyst detected in the first trimester by two- and three-dimensional sonography

A case of umbilical cord cyst was identified via 2-dimensional and 3-dimensional sonographic examination at 8 weeks' menstrual age. The cyst was solitary, measuring 18.0 mm, and it was located close to the placental insertion on the umbilical cord. The gestational sac and yolk sac diameters and the fetal heart rate were within normal ranges for menstrual age. Follow-up 3-Dimensional sonographic examination in the second trimester showed complete resolution of the cyst. Amniocentesis revealed a normal karyotype, and a normal infant was delivered at term.     

孕早、中期人体鱼序列征胎儿超声表现

目的 观察孕早、中期人体鱼序列征胎儿超声表现。方法 回顾性分析22胎经引产证实的人体鱼序列征胎儿超声表现，对比观察孕早、中期差异。结果 22胎中，9胎于孕早期诊断，超声表现为羊水量正常或略少，胎儿双下肢融合、足缺如或发育不良及单脐动脉起自高位腹主动脉，其中5胎双足并腿畸形、1胎单足并腿畸形，3胎无足并腿畸形，8胎(8/9,88.89%)合并其他结构畸形；13胎于孕中期诊断，超声表现为无羊水或羊水过少，胎儿双下肢融合、单脐动脉起自高位腹主动脉、肾脏发育不良，膀胱均未显示，其中4胎双足并腿畸形、3胎单足并腿畸形，6胎无足并腿畸形，9胎(9/13,69.23%)合并其他结构畸形。结论 人体鱼序列征胎儿孕早、中期典型超声表现包括并腿畸形及单脐动脉起自高位腹主动脉；孕早期羊水充足，为最佳诊断时机。     

羊水量正常时胎儿肾发育不良的超声诊断及临床意义

目的 探讨产前超声检查对于羊水量正常时胎儿肾发育不良的诊断价值和临床意义.方法 于孕中晚期对羊水量正常胎儿中发现的单侧或双侧肾超声表现异常(包括大小、回声、形态异常,出现囊肿等)病例进行系统二维超声检查、孕期及生后随访观察、病理学检查等,并进行总结分析.仅有肾盂增宽的胎儿不包括在本组研究中.结果 发现羊水量正常但单侧或双侧肾发育不良的胎儿11例.其中单侧多囊性肾发育不良5例,4例不合并其他异常,1例合并同侧手缺如;单侧肾缺如2例,其中1例不合并其他畸形,另1例合并多发畸形包括脑积水、骶尾部脊柱裂、同侧桡骨缺失及单脐动脉,符合VACTERL综合征;盆腔.肾1例,马蹄肾1例,生后超声证实;常染色体显性遗传多囊肾1例,胎儿一侧肾可见多发囊肿,合并心脏横纹肌瘤,孕妇为双侧多囊肾;双侧肾发育不良1例,产前超声表现为双侧肾回声增强.结论 单侧多囊性肾发育不良是羊水量正常时产前超声最常检出的胎儿肾发育不良性疾病.根据产前超声表现并结合家族史,能在大多数胎儿肾发育不良病例中进行病因学诊断并帮助判断预后.     

The cocoon sign: a potential sonographic pitfall in the diagnosis of twin - twin transfusion syndrome.

OBJECTIVES: To investigate the frequency and clinical importance of the cocoon sign in twin-twin transfusion syndrome (TTTS). METHODS: Charts and ultrasound images of all pregnancies with TTTS that underwent selective laser photocoagulation of communicating vessels at our institution over a 1-year period were retrospectively reviewed for a cocoon sign. TTTS had been diagnosed and prospectively staged if monochorionicity was suspected and the maximum vertical pocket (MVP) of amniotic fluid in one gestational sac was >/=8 cm, while the MVP in the other gestational sac was 相似文献   

Sonographic visualization of normal-size ovaries during pregnancy.

OBJECTIVE: To assess the ability of ultrasound to detect ovaries of normal size during pregnancy METHODS: A prospective study of 329 women with a normal pregnancy course was undertaken; 68 were excluded from analysis because of an enlarged, cystic ovary. Of the remainder, 60 pregnancies were examined in the first trimester and 201 in the second or third trimester. The first group underwent transvaginal (TVS) and transabdominal (TAS) scanning. The second group underwent TAS examination only. RESULTS: In the first-trimester group, TVS identified both ovaries in 57 patients (95%) and transabdominal ultrasound in 20 (33.3%). In the second- and third-trimester patients, TAS visualized both ovaries in 33 patients (16.4%), and neither ovary in 120 (59.7%). Both ovaries were less visible with advancing gestational age. The right ovary showed a significant change in position during pregnancy, from about 1 cm (at 15-24 weeks) to 2.5 cm (at 30-41 weeks) cranial to the iliac spine. The left ovary was found 1 cm above the iliac spine throughout pregnancy. CONCLUSIONS: Transvaginal sonography is adequate for the visualization of both ovaries in the first trimester of pregnancy. With advanced gestational age, the ovaries were significantly less visible by TAS. Sonographic scanning of the ovaries in second and third trimester should be concentrated mainly at the level of the iliac spine. Poor sonographic visualization of both ovaries in late gestation may mandate the use of other imaging modalities.     

The potential of multivariate discriminant analysis in the antenatal detection of neural tube defects

A method is described which improves the ability to distinguish between normal and neural tube-defective fetuses in utero. Early second trimester amniotic fluid is classified by stepwise discriminant analysis based upon biochemical analysis for alpha-fetoprotein and eight other easily assayed variables; classification is more reliable than using alpha-fetoprotein and gestational age alone.     

Prenatal diagnosis of a lean umbilical cord: a simple marker for the fetus at risk of being small for gestational age at birth.

OBJECTIVE: The purpose of this study was to investigate whether the prenatal diagnosis of a 'lean' umbilical cord in otherwise normal fetuses identifies fetuses at risk of being small for gestational age (SGA) at birth and of having distress in labor. The umbilical cord was defined as lean when its cross-sectional area on ultrasound examination was below the 10th centile for gestational age. METHOD: Pregnant women undergoing routine sonographic examination were included in the study. Inclusion criteria were gestational age greater than 20 weeks, intact membranes, and singleton gestation. The sonographic cross-sectional area of the umbilical cord was measured in a plane adjacent to the insertion into the fetal abdomen. Umbilical artery Doppler waveforms were recorded during fetal apnea and fetal anthropometric parameters were measured. RESULTS: During the study period, 860 patients met the inclusion criteria, of whom 3.6% delivered a SGA infant. The proportion of SGA infants was higher among fetuses who had a lean umbilical cord on ultrasound examination than among those with a normal umbilical cord (11.5% vs. 2.6%, p < 0.05). Fetuses with a lean cord had a risk 4.4-fold higher of being SGA at birth than those with a normal umbilical cord. After 25 weeks of gestation, this risk was 12.4 times higher when the umbilical cord was lean than when it was of normal size. The proportion of fetuses with meconium-stained amniotic fluid at delivery was higher among fetuses with a lean cord than among those with a normal umbilical cord (14.6% vs. 3.1%, p < 0.001). The proportion of infants who had a 5-min Apgar score < 7 was higher among those who had a lean cord than among those with normal umbilical cord (5.2% vs. 1.3%, p < 0.05). Considering only patients admitted in labor with intact membranes and who delivered an appropriate-for-gestational-age infant, the proportion of fetuses who had oligohydramnios at the time of delivery was higher among those who had a lean cord than among those with a normal umbilical cord (17.6% versus 1.3%, p < 0.01). CONCLUSION: We conclude that fetuses with a lean umbilical cord have an increased risk of being small for gestational age at birth and of having signs of distress at the time of delivery.     

COL2A1基因突变所致先天性脊柱骨骺发育不良的产前分子诊断

目的：对COL2A1基因（typeⅡcollagen gene）G504S突变导致的先天性脊柱骨骺发育不良（SEDC）家系的2例中期妊娠患者进行产前分子诊断。方法：分别对患者于19＋3孕周和18＋6孕周进行羊膜囊穿刺术抽取羊水,提取羊水脱落细胞DNA,对COL2A1基因的第23外显子扩增,对其产物测序。同时第1例胎儿从17＋3孕周～27＋3孕周、第2例胎儿从16＋1孕周～19＋1孕周对股骨长度进行B超动态检测。结果：COL2A1的23外显子测序结果显示第1例胎儿带有与母亲同样的COL2A1基因G504S突变。第2例胎儿COL2A1基因无突变。B超的追踪检测显示2例胎儿颅骨双顶径都与孕龄相符。第1例患病胎儿股骨增长随孕龄的增加而逐渐减慢,但孕23周前减慢不十分明显。病例2的胎儿股骨长度与孕龄相符,现继续妊娠观察。于第27＋5孕周对第1例患病胎儿行引产术后,影像学检测显示胎儿脊柱扁平、长骨明显短小,证实胎儿患有SEDC。结论：对于有SEDC风险的胎儿进行基因检测非常重要,可以在B超诊断前了解胎儿基因型并明确诊断。B超对胎儿股骨长度的动态检测有助于SEDC的诊断。     

Two-dimensional and M-mode echocardiography of the fetal coronary sinus.

OBJECTIVE: To document fetal coronary sinus dimensions in normal pregnancy. METHODS: Two hundred and sixty-five normal fetuses in which congenital cardiac defects had been excluded were examined cross-sectionally between 21 and 38 weeks of gestation. From the apical or basal four-chamber view the transducer was tilted towards the inferior cardiac surface in order to visualize the coronary sinus by real-time ultrasound. Maximum systolic and diastolic diameters were measured using M-mode. Reference ranges were constructed and the ratio of systolic and diastolic diameters calculated. Data from two fetuses, one with supraventricular tachycardia and a second one with hydrops secondary to anemia, were also compared. RESULTS: Visualization and measurement of the coronary sinus were successful in 258 (97.4%) patients. The coronary sinus systolic and diastolic diameters increased significantly with gestational age (maximum systolic diameter, 1.6 mm at 21 weeks to 4 mm at 38 weeks; maximum diastolic diameter, 0.9 mm at 20 weeks to 2.2 mm at 38 weeks). The ratio of systolic to diastolic diameters remained relatively constant (range, 1.7-2.1) and therefore was unrelated to gestational age. In the fetuses with supraventricular tachycardia and hydrops, both diameters of the coronary sinus were increased and diminished fluctuation in size during the cardiac cycle was observed. CONCLUSIONS: The described sonographic approach provides an effective method for measurement of coronary sinus dimensions. The normative data may facilitate the detection of coronary sinus dilation as an indirect marker for abnormalities in venous return to the heart.     

Effect of amniotic fluid volume on ultrasonic fetal weight estimation.

We evaluated the relationship between the amniotic fluid index and the accuracy of fetal weight estimation using ultrasonography. Six hundred and sixty-four patients, between 20 and 42 weeks' gestational age, who were delivered within 1 week of a sonographic examination were studied. Five formulas for estimating fetal weight also were studied. Systematic and random errors in predicting birth weight were analyzed relative to birth weight and amniotic fluid index. The accuracy of sonographic fetal weight estimation was independent of amniotic fluid index across all gestational ages and birth weights. Each of the five formulas had similar error percentages, and no significant differences were detected. Predicted fetal weight was significantly underestimated with each of the formulas studied, a finding that was also independent of birth weight and amniotic fluid index. We conclude that ultrasonography can be used reliably to estimate fetal weight in patients with altered amniotic fluid volumes.     

Sonographic measurement of amniotic fluid volume in the first trimester of pregnancy.

The sonographic estimate of amniotic fluid volume from 7 to 13 weeks of gestation in 95 pregnancies was calculated. Amniotic fluid volume increased from 1.5 ml at 7 weeks to 25 ml at 10 weeks and 100 ml at 13 weeks. The nomograms constructed may be used in the objective evaluation of the fetal condition in the first trimester.     

Reactivity of amniotic fluid alpha-fetoprotein with concanavalin A-sepharose in pre-natal diagnosis of fetal malformations

The proportion of concanavalin A-non-reactive alpha-fetoprotein was determined in 215 amniotic fluid samples from second trimester pregnancies. the median percentage for concanavalin A-non-binding alpha-fetoprotein was 35.5% at the 15th week and 32.2% at the 18th gestational week. Nineteen of the 23 pregnancies with various fetal malformations showed highly elevated total alpha-fetoprotein levels. In this group, the value for non-reactive alpha-fetoprotein was below the normal range in 12 out of 13 samples collected at 15-17 weeks of pregnancy and in four out of six samples at 18-19 weeks. Four pathological pregnancies had only moderately elevated total alpha-fetoprotein levels (5.3-7.9 SD above the mean) and two of these samples had a low percentage of the concanavalin A-non-binding fraction. The amniotic fluid alpha-fetoprotein concentration was between 3 and 5 SD and over 5 SD above the mean in four and seven normal pregnancies, respectively. The concanavalin A-fractionation classified correctly 10 out of these 11 cases. The results indicate that the determination of the proportion of concanavalin A-non-binding alpha-fetoprotein is a useful supplementary test to the total alpha-fetoprotein assay.     

Prenatal diagnosis of diastematomyelia: presentation of eight cases and review of the literature.

OBJECTIVES: Diastematomyelia is a rare form of spinal dysraphism. We present eight cases of diastematomyelia diagnosed prenatally in our institution as well as a review of the literature in order to determine the prognosis of isolated cases of this very unusual condition. METHODS: Records of fetuses with diastematomyelia diagnosed in our institution between January 2000 and June 2005 were collected. All liveborn fetuses were examined by a pediatric neurologist. Pre- and postnatal data were analyzed. A search was then conducted using PubMed to review previously reported cases in the literature. RESULTS: Eight cases of diastematomyelia were diagnosed during the study interval. The mean (range) gestational age at diagnosis was 21 (13-25) weeks. The main sonographic findings were widening of the spinal canal in the coronal view and an additional echogenic focus in the posterior part of the spinal column in the axial view. The diagnosis of associated open spina bifida was made in one fetus with elevated levels of amniotic fluid alpha-fetoprotein (AF-AFP) and acetylcholinesterase (AF-AChE) and the pregnancy was terminated. The other seven cases of diastematomyelia had normal levels of AF-AFP and AF-AChE and were considered isolated. One pregnancy miscarried spontaneously 1 week following amniocentesis and the remaining six were delivered at term. Review of the literature revealed 14 reports involving 26 cases of prenatally diagnosed diastematomyelia. Twelve cases had normal biochemistry and/or no additional abnormalities and all had a favorable outcome. CONCLUSIONS: When diastematomyelia is not associated with other spinal anomalies, the prognosis is favorable. Prenatal diagnosis is generally made in the second trimester but sonographic signs may be recognized as early as the first trimester. Intrauterine diagnosis of diastematomyelia should facilitate appropriate management of affected cases.