Absence of a relationship between umbilical cord thickness and coiling patterns.

OBJECTIVE: The purpose of this study was to evaluate a relationship between the umbilical cord thickness and cord coiling patterns during the fetal sonographic anatomic survey in the second trimester of pregnancy. METHODS: This was a prospective study of 470 patients with singleton pregnancies who had a fetal anatomic survey with recorded umbilical coiling patterns between 18 and 23 weeks' gestation. The umbilical cord thickness was assessed as an umbilical diameter at the level of the fetal abdominal cord insertion and compared with the antenatal umbilical coiling index (aUCI), calculated as a reciprocal value of the distance between a pair of umbilical cord coils. RESULTS: Three hundred twenty-one patients had adequate sonographic umbilical cord images and maternal demographic, antenatal, and labor data to meet inclusion criteria. The mean aUCI was 0.41 with 10th and 90th percentiles of 0.21 and 0.60, respectively. A total of 10.6% (34/321) and 9.3% (30/321) of patients were categorized as having hypocoiled and hypercoiled umbilical cords, respectively. The mean cord diameter +/- SD was 9.48 +/- 0.97 mm (range 7.0-12.5 mm). There was no statistically significant correlation between aUCI and umbilical cord thickness (P = .1164). CONCLUSIONS: An aUCI, or umbilical coiling pattern, does not correlate with umbilical cord thickness. It appears that a lesser amount of the umbilical supportive tissue, mainly Wharton jelly, is not related to an increased umbilical cord coiling pattern.     

UMBILICAL COILING INDEX: IS IT A MARKER FOR THE FOETUS AT RISK?

SUMMARY The aim of this study was to determine the relationship between the number of coils in the umbilical cord and perinatal outcome. The umbilical cords and delivery records of 147 liveborn neonates were prospectively studied. The umbilical coiling index (UCI) of each cord was calculated by dividing the total number of complete umbilical vascular coils by the umbilical cord length. Subjects with UCIs below the 10th percentile, above the 90th percentile, and between the 10th and 90th percentiles were defined as hypocoiled, hypercoiled, and normocoiled, respectively. Several different parameters were used to measure neonatal outcome. The mean UCI was 0.20 ± 10 (SD). No relationship was noted between UCI and maternal age, gravidity, parity, oligohydramnios, or birth weight. When we compared the hypocoiled group (n=30) with the normocoiled group (n=87), we detected a statistically significantly higher incidence of meconium staining, interventional delivery, apgar scores, fetal blood pH and intrapartum fetal heart rate disturbances. As a result, we concluded that the UCI has a strong relationship with perinatal outcome and may be used antenatally as a marker for identifying the fetus at risk.     

Antenatal umbilical coiling index and Doppler flow characteristics.

OBJECTIVE: To evaluate whether a relationship exists between the antenatal umbilical coiling index (UCI) and umbilical cord Doppler flow characteristics. METHODS: During the fetal anatomical survey in 200 consecutive pregnant patients at 18-23 weeks' gestation, we recorded umbilical coiling patterns and blood flow characteristics. The antenatal UCI, calculated as a reciprocal value of the distance between a pair of umbilical cord coils, was compared with Doppler parameters including umbilical vein blood flow volume (in mL/min/kg), and mean resistance index (RI) and peak systolic velocity (PSV in cm/s) averaged from both umbilical arteries. RESULTS: A total of 154 patients met the inclusion criteria of singleton pregnancy and having adequate sonographic umbilical cord images, Doppler flow indices, and all demographic, antenatal and labor data. The mean antenatal UCI was 0.40, with 10th and 90th centiles of 0.20 and 0.60, respectively. The mean +/- SD umbilical artery RI and PSV and umbilical vein blood flow volume were 0.74 +/- 0.07, 25.1 +/- 6.4 cm/s, and 264 +/- 106 mL/min/kg, respectively. All Doppler variables correlated significantly with antenatal UCI, with lower RI and higher PSV and umbilical vein blood flow volume values being associated with higher antenatal UCI (P = 0.016, P < 0.001, and P = 0.032, respectively). However, when stratified by antenatal UCI into hyper- (above 90th centile), normo- (10th-90th centile), and hypocoiled (below 10th centile) umbilical cord groups, a significant difference was observed for PSV only (P = 0.016). CONCLUSION: It appears that umbilical cord coiling modulates noticeably blood flow through the umbilical cord. We speculate that more prominent umbilical coiling (higher antenatal UCI values) has a protective effect on blood flow in terms of decreased arterial resistance and higher blood flow velocities, as well as increased venous blood flow. However, due to lack of significant differences between Doppler characteristics when stratified by antenatal UCI into hypo-, normo-, and hypercoiled groups, the clinical implications of this observation are uncertain.     

Second-trimester ultrasonographic assessment of the umbilical coiling index.

OBJECTIVE: To determine the relationship between gestational age and the ultrasonic measurement of umbilical coiling index (UCI), and to assess the ability of second-trimester ultrasonic measurements of UCI to predict the true UCI, determined at birth. SUBJECTS/METHODS: Five hundred and thirty-one consecutive women with uncomplicated pregnancies, booking for delivery with a singleton pregnancy, were recruited during a routine second-trimester fetal morphology scan. Multiple ultrasonographic measurements of the intercoil distance were performed between two to three coils of the umbilical cord, along its entire visible length. Three hundred and seventy-four patients (70%) were followed until delivery when the true UCI was measured. RESULTS: An adequate portion of umbilical cord for assessment of coiling was visualized in 99% of cases. Adequate ultrasonographic visibility rates for the fetal, middle and placental regions of the cord were different. All three regions of the umbilical cord could only be visualized adequately in 10% of cases, and two regions were visible in 75%. The UCI progressively decreased along the cord from the fetal insertion to the placental insertion. The mean decrease in UCI with increasing gestational age was similar in all parts of the cord before the 23rd week (160 days) of pregnancy, and plateaued off after this point, except in measurements performed near the fetal insertion. The sensitivity of second-trimester ultrasound examination for predicting hypercoiling at birth was 17.3% and for predicting hypocoiling was 9.1%. DISCUSSION: Whilst UCI can be measured easily and reliably in the second trimester these estimates do not accurately reflect the UCI at term. Our original assumption that umbilical coiling does not alter after the initial formation of coils in the first trimester is incorrect; mixed patterns occurred in about 25% of cases. These patterns develop during the second and third trimesters, presumably due to snarls in the cord, and influence the final coiling number and therefore the relationship between the two measurements of UCI.     

彩超评估脐带旋转指数与脐带异常附着的相关性研究

目的：观察脐带旋转指数异常与脐带附着异常是否相关。方法：超声检测350例孕晚期胎儿的脐带旋转指数（1／A）。该指数为脐动脉围绕脐静脉旋转1个周期后占脐静脉的长度的倒数,指数小于0．1考虑为少旋转。分娩后测量脐带附着点到胎盘边缘的距离,将结果分为正常附着、边缘性附着和帆状附着。结果：少旋转组的胎儿脐带约有76．5％为异常附着,正常旋转或高旋转约有2．2％的脐带异常附着,胎儿脐带旋转指数与脐带附着点到胎盘边缘距离之间的相关系数为r=0．953。结论：脐带少旋转与脐带异常附着有显著相关性,若存在脐带少旋转则可提示存在脐带异常附着。     

Sonographic evaluation of umbilical cord insertion with umbilical coiling index.

PURPOSE: The aim of this study was to investigate the association between umbilical cord hypocoiling and abnormal placental insertion of the umbilical cord. METHODS: Umbilical coiling was measured by sonography in 253 pregnant women in their second or third trimester. An umbilical coiling index, defined here as the reciprocal of the length of 1 umbilical vascular coil, of less than 0.1 was considered hypocoiled. The distance from the placental edge to the insertion of the umbilical cord was measured after delivery, and the results were used to classify cord insertion as normal, marginal, or velamentous. RESULTS: Cord insertion was abnormal in 66.7% of the fetuses with umbilical hypocoiling but in only 1.3% of those whose coiling index was > or = 0.1 (p < 0.05). CONCLUSIONS: Hypocoiling of the umbilical cord was highly associated with abnormal cord insertion. The presence of a hypocoiled umbilical cord may indicate the presence of abnormal cord insertion and thus may be useful for obstetric management.     

Prenatal ultrasonographic prediction of the umbilical coiling index at birth and adverse pregnancy outcome.

OBJECTIVES: To evaluate whether the antenatal umbilical coiling index (aUCI) as measured by ultrasonography predicts the postnatal umbilical coiling index (pUCI) and adverse pregnancy outcome. METHODS: In a prospective study in 117 pregnancies, the aUCI was measured between 28 weeks and term by ultrasonography. The aUCI was calculated as the reciprocal value of the mean pitch of one complete coil. The pUCI was calculated as the number of coils divided by the cord length in cm. The correlation between aUCI and pUCI was assessed and likelihood ratios for adverse pregnancy outcome were calculated. RESULTS: We had complete data on 81 subjects. Mean aUCI +/- SD was 0.30 +/- 0.09 and mean pUCI +/- SD was 0.17 +/- 0.08. The correlation coefficient between aUCI and pUCI was 0.66, P < 0.001. Limits of agreement were 0-0.28 coils/cm. The positive likelihood ratio for small-for-gestational-age infants was 2.6 (95% confidence interval (CI) 0.6-11.6) for ultrasound hypocoiling, and 5.7 (95% CI 1.3-24.8) for ultrasound hypercoiling. The positive likelihood ratio for interventional delivery for non-reassuring fetal status was 1.2 (95% CI 0.2-9.0) for ultrasound hypocoiling, and 10.3 (95% CI 2.1-50.2) for ultrasound hypercoiling. CONCLUSIONS: Strong correlation coefficients comparing the aUCI and pUCI do not reflect agreement. Since the limits of agreement were almost as wide as the full range for the pUCI, the aUCI does not predict the pUCI with sufficient precision. Larger prospective studies are required to confirm the predictive potential of the aUCI for adverse pregnancy outcome.     

Early second-trimester low umbilical coiling index predicts small-for-gestational-age fetuses.

OBJECTIVE: To evaluate the role of the early second-trimester Doppler velocimetric studies of the umbilical coiling index and umbilical cord cross-sectional area as tests for the prediction of small-for-gestational age infants. METHODS: Doppler blood flow studies in 147 singleton pregnancies at risk for delivery of a small-for-gestational-age neonate were performed at 15 +/- 1 (SD) weeks' gestation from the uterine artery, umbilical artery, middle cerebral artery, inferior vena cava, and ductus venosus. Pulsatility index values were calculated for the arteries, and preload index values and systolic-atrial contraction ratios were calculated for the veins. The sonographic cross-sectional area of the umbilical cord was measured in a plane adjacent to the insertion into the fetal abdomen. The umbilical coiling index was calculated by using sonographic longitudinal views of cord vessels from several segments antenatally and by dividing the total number of helices by cord length (centimeters) postnatally. Small-for-gestational-age neonates were identified when the birth weight was below the 10th percentile for gestational age. RESULTS: Among 147 pregnancies studied, 124 fulfilled the study criteria. Thirty-nine of the neonates were small for gestational age at birth (31.5%). The mean +/- SD gestational age at delivery of the appropriate-for-gestational-age neonates was 39.7 +/- 1.28 weeks, and that of the small-for-gestational-age neonates was 36.4 +/- 2.9 weeks (range, 28-40 weeks). The best single predictor of a small-for-gestational-age infant was the coiling index, with sensitivity of 79%, specificity of 86%, a positive predictive value of 72%, and a negative predictive value of 90%. CONCLUSIONS: The umbilical coiling index measured in the second trimester is useful in predicting the birth of a small-for-gestational-age infant and may serve as a marker for subsequent growth restriction.     

Umbilical vein blood flow in fetuses with normal and lean umbilical cord.

OBJECTIVE: To evaluate whether umbilical vascular coiling is correlated with the umbilical vein blood flow profile and to investigate if this is different between fetuses with a lean and those with a normal umbilical cord. METHODS: Consecutive women with a singleton gestation who delivered at term and who underwent an ultrasound examination within 24 h from delivery were studied. Umbilical cord and vessel areas were calculated. Umbilical vein blood flow parameters were obtained by digital color Doppler velocity profile integration. After delivery, the umbilical coiling index was calculated. RESULTS: One hundred and sixteen women were studied. Twelve (10.3%) had a lean umbilical cord (area < 10th centile). A significant correlation was found between the umbilical coiling index and the umbilical vein blood flow (r = 0.67, P < 0.001). A significant difference between fetuses with and without a lean cord was found in terms of: umbilical coiling index (0.18 +/- 0.08 vs. 0.29 +/- 0.09, P < 0.005), cord area (87.6 +/- 5.1 mm2 vs. 200.6 +/- 34.6 mm2, P < 0.001), Wharton's jelly amount (25.7 +/- 10.3 mm2 vs. 122.1 +/- 33.4 mm2, P < 0.001), umbilical vein blood flow (93.7 +/- 17.8 ml/kg per min vs. 126.0 +/- 23.4 ml/kg per min, P < 0.001), and umbilical vein blood flow mean velocity (6.6 +/- 2.7 cm/s vs. 9.0 +/- 3.6 cm/s, P < 0.05). The proportion of fetuses with an umbilical vein blood flow < 80 ml/kg per min was higher when the cord was lean than when it was normal (25% vs. 1.9%, P < 0.01). CONCLUSIONS: Lean umbilical cords differ from normal cords not only from a structural point of view but also in the umbilical vein blood flow characteristics. This could explain the increased incidence of intrapartum complications and fetal growth restriction among fetuses with a lean and/or hypocoiled cord.     

Large cross-sectional area of the umbilical cord as a predictor of fetal macrosomia.

OBJECTIVE: To determine whether a large cross-sectional area of the umbilical cord is a predictor of fetal macrosomia. METHODS: Consecutive patients of > 34 weeks' gestation, who presented for sonographic examination and who delivered within 4 weeks of the examination, were included in the study. The sonographic cross-sectional areas of the umbilical cord, the umbilical vessels and the Wharton's jelly were measured in a free loop of the umbilical cord. Logistic regression analysis was used to determine significant predictors of macrosomia (actual birth weight > 4000 g and > 4500 g). Fetal biometric parameters (biparietal diameter, abdominal circumference and femur length), sonographic estimated fetal weight and umbilical cord area > 95(th) centile for gestational age were used as covariates. RESULTS: During the study period, 1026 patients were enrolled. Fifty-three (5.2%) newborns had a birth weight > 4000 g, and 22 (2.1%) weighed > 4500 g. The proportion of cases with a large umbilical cord was significantly higher in the group of macrosomic compared with non-macrosomic infants (54.7% vs. 8.7%, P < 0.0001). Multiple regression models demonstrated an independent contribution of the large cord in the prediction of birth weight > 4000 g and > 4500 g (odds ratio (95% CI), 20.6 (9.2-45.9) and 4.2 (1.2-17.7), respectively). The sensitivity, specificity and positive and negative predictive values of a sonographic large umbilical cord were 54.7%, 91.3%, 25.4%, and 97.4%, respectively. The combination of abdominal circumference > 95(th) centile and large cord predicted 100% of macrosomic infants. The proportion of umbilical cords with a Wharton's jelly area > 95(th) centile for gestation was significantly higher in macrosomic fetuses of diabetic compared with non-diabetic mothers. CONCLUSIONS: Sonographic assessment of umbilical cord area may improve the prediction of fetal macrosomia.     

Characteristics of blood flow in intrauterine growth-restricted fetuses with hypercoiled cord.

OBJECTIVE: To clarify the characteristics of fetoplacental blood flow of growth-restricted fetuses with hypercoiled umbilical cord. SUBJECTS: Eight growth-restricted fetuses with hypercoiled cord. METHODS: Flow velocity waveforms of the umbilical cord artery and vein, fetal abdominal aorta and fetal inferior vena cava were analyzed. RESULTS: The resistance index in the umbilical artery in the hypercoiled cases was lower than that in normal fetuses. Early-diastolic reversed flow was observed in the abdominal aorta in some cases. In all cases, umbilical venous pulsation was observed in the entire cord until delivery. In one case, fetal heart failure occurred, resulting in pre-mature delivery. An atrophic type of single umbilical artery was observed in four cases. CONCLUSION: Fetal blood flow disturbance caused by a hypercoiled umbilical cord may be a cause of growth restriction.     

First-trimester sonographic umbilical cord diameter and the growth of the human embryo.

OBJECTIVES: Experimental and clinical evidence have shown that the morphometry of the umbilical cord in the second half of gestation might be useful in predicting adverse perinatal outcome. The purposes of this study were to generate a nomogram for the umbilical cord diameter in the first trimester and, in an observational study, to investigate whether the sonographic measurement of the umbilical cord diameter early in gestation has the same clinical value as that late in gestation. METHODS: The sonographic umbilical cord diameter, crown-rump length and biparietal diameter were measured in 439 fetuses at between 8 and 15 weeks of gestation. The perinatal outcome was recorded for all patients. RESULTS: The umbilical cord diameter increased steadily from 8 to 15 weeks of gestation. A significant correlation was found between umbilical cord diameter and gestational age (r = 0.78; P < 0.001), umbilical cord diameter and crown-rump length (r = 0.75; P < 0.001) and umbilical cord diameter and biparietal diameter (r = 0.81; P < 0.001). No correlation was found between umbilical cord diameter values and either birth weight or placental weight. Among patients who had a miscarriage (n = 7) and pre-eclampsia (n = 8) the umbilical cord diameter was below 2 standard deviations from the mean in three cases (42.9%) and three cases (37.5%), respectively. CONCLUSION: The measurement of the umbilical cord diameter in the first trimester is correlated with the growth of the embryo and may be a marker for identifying a subset of fetuses at risk of spontaneous miscarriage and pre-eclampsia.     

Three-dimensional power Doppler sonography in the prenatal diagnosis of a true knot of the umbilical cord: value and limitations.

OBJECTIVE: The purpose of this study was to examine the value of 3-dimensional power Doppler sonography in the prenatal diagnosis of a true knot of the umbilical cord. METHODS: Cases in which the diagnosis of a true knot of the umbilical cord was suspected by prenatal 2-dimensional sonography were reviewed. The presumably affected segment of the cord was examined with 3-dimensional power Doppler sonography for further characterization. Confirmation of the prenatal diagnosis was sought by reviewing the delivery records and contacting the referring obstetrician and the patients themselves. RESULTS: Eight consecutive cases were studied. Three-dimensional power Doppler sonography displayed a vascular spatial configuration pattern consistent with a true knot of the umbilical cord in all of them. However, the prenatal diagnosis was confirmed at delivery in only 5 cases (62.5%). Although there were no cases of a false knot mimicking a true knot of the umbilical cord, all incorrect diagnoses in this series were associated with multiple loops of the umbilical cord in the third trimester. CONCLUSIONS: Three-dimensional power Doppler sonography seems to be helpful in determining the presence of a true knot of the umbilical cord in utero, especially in the second trimester. However, this should not be considered a definitive method for the diagnosis because multiple loops of the umbilical cord lying close to each other can generate a sonographic image that can be undistinguishable from a true knot of the umbilical cord prenatally, especially when located in a small pocket of amniotic fluid. Therefore, the presumable diagnosis of a true knot of the umbilical cord in utero should be taken with caution.     

Abnormal ductus venosus blood flow: a clue to umbilical cord complication.

We report a case of umbilical cord complication causing, fetal hypoxemia and acidemia. At 30 weeks of gestation, the patient was referred because of slightly increased amniotic fluid volume and a non-reactive cardiotocogram. Biometry was appropriate for gestational age. Umbilical artery and fetal aortic Doppler findings were normal, whereas diastolic blood flow velocities in the middle cerebral artery were increased and the ductus venosus showed severely abnormal flow velocity waveforms with reversal of flow during atrial contraction. Since other reasons for fetal hypoxemia could be excluded, careful examination of the umbilical cord was performed. Traction of the hypercoiled umbilical cord due to its course around the fetal neck and shoulders was suspected. Cesarean section confirmed the sonographic findings and fetal blood gases revealed fetal acidemia. This case indicates that investigation of fetal venous blood flow may also help to identify fetal jeopardy due to reasons other than increased placental vascular resistance.     

Umbilical cord morphologic characteristics and umbilical artery Doppler parameters in intrauterine growth-restricted fetuses.

OBJECTIVE: To compare prenatal morphometric changes of umbilical cord components in intrauterine growth-restricted fetuses with and without abnormal umbilical artery Doppler parameters. METHODS: Consecutive singleton intrauterine growth-restricted fetuses at a gestational age of older than 20 weeks were compared with matched appropriate-for-gestational-age fetuses. Intrauterine growth restriction was defined in the presence of a sonographic abdominal circumference below the 5th percentile for gestational age at the time of sonography and a birth weight below the 10th percentile. The sonographic examination included pulsed Doppler measurements of the umbilical artery resistance index and measurements of the umbilical cord cross-sectional area and the umbilical cord vessel area. RESULTS: A total of 84 intrauterine growth-restricted fetuses and 168 appropriate-for-gestational-age fetuses were included in the study. All umbilical cord components (umbilical cord cross-sectional area, vein area, artery area, and Wharton jelly area) were smaller in the intrauterine growth-restricted fetuses. The prevalence of lean umbilical cords (cross-sectional area < 10th percentile for gestational age) was significantly higher in intrauterine growth-restricted fetuses compared with appropriate-for-gestational-age fetuses (73.8% versus 11.3%; P < .0001). A significant and progressive reduction of the umbilical vein area corresponding to the degree of umbilical artery Doppler parameter abnormality was found. The umbilical artery area was not related to the hemodynamic changes of the blood flow in the umbilical arteries. CONCLUSIONS: The proportion of lean umbilical cords was higher in intrauterine growth-restricted fetuses than in appropriate-for-gestational-age fetuses. Umbilical vein caliber decreases significantly with worsening of umbilical artery Doppler parameters.     

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.     

Megacystis Associated With an Umbilical Cord Cyst

Objective. The purpose of this series was to report the first‐trimester sonographic findings, antenatal course, and outcome in fetuses with a patent urachus. Methods. We conducted a review of ultrasound reports and medical charts from 3 pregnancies complicated by a congenital patent urachus detected in the first trimester. Results. All 3 fetuses had megacystis and an umbilical cord cyst close to the fetal abdominal insertion that was detected in the first trimester. In 2 cases, the megacystis resolved spontaneously while the umbilical cord cyst worsened in appearance; among them, massive edema of the umbilical cord was documented in 1, and evidence of partial bladder exstrophy was detected in the third trimester in the other. Both cases required neonatal surgery with no complications. In the remaining case, the fetus died in the early second trimester. Postmortem examination confirmed the diagnosis of a patent urachus, an allantoic cyst, and thrombosis of the umbilical vessels. Conclusions. Megacystis is a warning sign of a patent urachus in the first trimester. The prognosis of this condition is generally good; however, fetal death can occur secondary to compression of umbilical vessels due to the expanding allantoic cyst.     

Ductus venosus blood flow velocity characteristics of fetuses with single umbilical artery.

OBJECTIVES: Sonographic Doppler evaluation of the fetal ductus venosus has been proved to be useful in the evaluation of fetal cardiac function. The aim of this study was to investigate the ductus venosus blood flow profile in fetuses with single umbilical artery and to correlate it with the umbilical cord morphology. METHODS: Fetuses at >20 weeks' gestation with single umbilical artery who were otherwise healthy were consecutively enrolled into the study. The sonographic examination included evaluation of the following Doppler parameters: umbilical artery resistance index, maximum blood flow velocity of the ductus venosus during ventricular systole (S-peak) and atrial contraction (A-wave), ductus venosus time-averaged maximum velocity (TAMXV), and pulsatility index for veins (PIV). The cross-sectional area of the umbilical cord and its vessels were measured in all cases. The Doppler and morphometric values obtained were plotted on reference ranges. RESULTS: A total of 88 fetuses with single umbilical artery were scanned during the study period. Of these 52 met the inclusion criteria. The S-peak velocity, A-wave velocity, and TAMXV were below the 5th centile for gestational age in 57.7%, 59.6%, and 57.7% of cases, respectively. The PIV was within the normal range in 80.1% of cases. The umbilical vein cross-sectional area of fetuses with single umbilical artery was above the 95th centile for gestational age in 34.6% cases. CONCLUSIONS: The ductus venosus blood flow pattern is different in fetuses with single umbilical artery from that in those with a three-vessel cord. This difference may be caused in part by the particular morphology of umbilical cords with a single artery.     

Sirenomelia sequence: first-trimester diagnosis with both two- and three-dimensional sonography.

OBJECTIVE: To describe the sonographic findings of sirenomelia during the first trimester on both two-dimensional sonography with color Doppler imaging and three-dimensional sonography. METHODS: Two cases of sirenomelia in primiparous patients with histories of infertility are described. The diagnosis was made on the basis of two-dimensional sonography, and three-dimensional sonography was used to further characterize the findings. RESULTS: Both fetuses had size-date discrepancies, increased nuchal translucency, large intra-abdominal vessels, and 2-vessel umbilical cords. Both pregnancies were terminated by dilation and curettage after the patients viewed the three-dimensional pictures of the fetuses. CONCLUSIONS: During the first trimester of pregnancy, rare and lethal anomalies can be diagnosed with a high degree of confidence if a thorough, age-dependent anatomic survey of the fetus is performed.     

Ultrasonographic diagnosis of trisomy 18: is it practical in the early second trimester?

The objective of this paper was to determine the rate of prenatal detection of ultrasonographic abnormalities in fetuses with trisomy 18 during the early second trimester. Our prenatal diagnosis database (encompassing January 1987 to June 1996) was searched for all patients referred for prenatal genetic evaluation between 14 and 22 weeks of gestation and who were found to have a fetus with a trisomy 18 karyotype. The sonographic reports and films were evaluated for the presence or absence of fetal anatomic abnormalities. Thirty-five fetuses were identified with a mean age of 17.3+/-2.0 (standard deviation) weeks. Thirty of the 35 (86%) had at least one detected abnormality. Most fetuses had more than one abnormality, with the mean number of abnormalities per fetus being three (range, 0 to 6). The most common abnormalities noted were persistent abnormal position of fetal fingers (89%); choroid plexus cysts (43%); abnormally shaped fetal head (strawberry or lemon) (43%); two-vessel umbilical cord (40%); cardiac defects (37%); intrauterine growth restriction (29%); omphalocele (20%); neural tube defects (9%); and cystic hygroma or lymphangiectasia (14%). Abnormalities of amniotic fluid volume (12%) and renal defects (9%) were seen less frequently. These data suggest that in the early second trimester, the time of most routine screening ultrasonographic examinations, most but not all fetuses with trisomy 18 have sonographically detectable anatomic abnormalities. The fetal hand appears to be abnormal in most early second trimester fetuses with trisomy 18, but the abnormality may be subtle and or unilateral.