Biomedical subjects
W Sepulveda
Publications and source records attributed to W Sepulveda.
Glioependymal and arachnoid cysts: unusual causes of early ventriculomegaly in utero.
In this report we describe two cases of fetal midline intracranial cyst presenting with ventriculomegaly at routine detailed second-trimester scan. In the first case, additional findings included a banana-shaped hypoplastic cerebellum and macrocephaly; autopsy after termination of the pregnancy revealed a glioependymal cyst. In the second case, subsequent follow-up examination revealed a progressive increase in cyst size and worsening of ventriculomegaly; termination of pregnancy was performed at 24 weeks and autopsy confirmed an arachnoid cyst. These cases document interhemispheric cyst as a cause for early ventriculomegaly in utero.
Echogenic material in the fetal gallbladder in a surviving monochorionic twin.
Fetal gallstones or echogenic sludge in the fetal gallbladder have rarely been reported prenatally despite the increasing number of ultrasound scans performed during pregnancy. In this report we present a case in which diffuse echogenic material was detected in the fetal gallbladder in a surviving monochorionic twin. This report identifies another predisposing factor for fetal gallstones/sludge in the perinatal period.
Prevalence of cystic fibrosis mutations in pregnancies with fetal echogenic bowel.
OBJECTIVE: To determine the prevalence of the most common cystic fibrosis mutations in pregnancies complicated by fetal echogenic bowel by using DNA testing. METHODS: Forty-five pregnancies with fetal echogenic bowel were studied prospectively for cystic fibrosis mutations. Using polymerase chain reaction, DNA from fetal amniocytes (n = 21), fetal blood (n = 5), or parental blood (n = 19) was amplified and tested for delta F508, G551D, G542X, and 621 + 1G-->T cystic fibrosis mutations, which account for about 85% of the mutations in the British population. In selected cases, further mutations were tested according to the parental ethnic background. RESULTS: Only one of the 26 fetuses screened was heterozygous for cystic fibrosis mutations. Among 38 parental samples screened from the remaining 19 pregnancies, cystic fibrosis mutations were detected in two cases, only one of the parents being a carrier in each case. The prevalence of cystic fibrosis carrier status in fetal and parental samples (1:26 and 1:19, respectively) is within the expected prevalence in the British population (1:25). No fetuses were affected by cystic fibrosis in this series, but five were found to have growth restriction, two trisomy 21, two congenital infection, and two bowel obstruction. CONCLUSION: Our results suggest that ultrasonographic detection of fetal echogenic bowel is not associated with an increased prevalence of cystic fibrosis mutations in pregnancies at low risk for this disease.
Amniotic fluid culture failure: clinical significance and association with aneuploidy.
OBJECTIVE: To characterize clinical aspects associated with second-trimester amniotic fluid (AF) culture failure. METHODS: The reports of all amniocentesis samples received in our cytogenetic laboratory over a 9-year period were reviewed to identify cases in which culture failure of amniocytes occurred. Medical records were then reviewed for the prenatal ultrasonographic findings, karyotype when available, and clinical outcome. RESULTS: During the study period, 4134 second-trimester AF samples were processed, of which 42 (1%) failed to yield a result. Complete information was available in 41 pregnancies, which are the basis of this report. Karyotyping was done ultimately in 32 of the 41 cases (78%). The frequency of an abnormal karyotype was greater in those pregnancies in which AF culture failure occurred in comparison with those in which a cytogenetic result was obtained (six of 32 [19%] versus 149 of 4092 [4%], P < .001). There was also a greater prevalence of fetal abnormalities detected on prenatal ultrasonography, mainly oligohydramnios, hydrops, and fetal growth restriction, in the AF culture failure group compared with the successful AF culture group (17 of 41 [41%] versus 351 of 4092 [9%1, P < .001). All chromosomally abnormal fetuses had anomalies detected at ultrasonography. CONCLUSION: Our findings confirm the previously reported association between karyotype abnormality and AF culture failure, but suggest that this association is probably due to fetal anomalies, detectable on prenatal ultrasonography, that lead to decreased fetal cell shedding.
Fetal seizures: further observations.
BACKGROUND: Previous reports of ultrasonographically diagnosed seizure activity in utero have described fetuses with obvious, gross, tonic-clonic movements of trunk and extremities. CASES: Three fetuses with akinesia deformation sequence are described: two with arthrogryposis multiplex congenita and one with Pena-Shokeir syndrome. Each was demonstrated by serial real-time ultrasound examinations to have joint contractures, absent fetal breathing motions, and lack of gross movements other than sonographically evident subtle seizure activity. CONCLUSION: Fetal seizure activity can be subtle when seen in the presence of fetal anomalies that limit joint movement. The prognosis remains poor.
Prenatal determination of chorionicity in triplet pregnancy by ultrasonographic examination of the ipsilon zone.
OBJECTIVE: To determine chorionicity in triplet pregnancies by ultrasonographic assessment of the ipsilon zone, the junction of the three interfetal membranes. METHODS: The thickness of the component membranes in the ipsilon zone was studied to determine chorionicity in 28 triplet pregnancies, by retrospective examination of the ultrasonographic images taken at 9-24 weeks' gestation, and in 20 consecutive triplet pregnancies followed prospectively by targeted ultrasonography at 8-21 weeks' gestation. Prenatal ultrasonographic findings were compared with those obtained from the records of the infertility centers or referring hospitals (the number of gestational sacs and live embryos in each sac seen by transvaginal scanning at 6-7 weeks' gestation). RESULTS: Of the 28 triplet pregnancies with appropriate images demonstrating the ipsilon zone, 22 were classified as trichorionic, five dichorionic, and one monochorionic. This classification was correct in all but one trichorionic pregnancy, which was misclassified as dichorionic. In the prospective subset (n = 20) there were 16 trichorionic and four dichorionic triplet pregnancies. The ipsilon zone was not present in one case in which the interfetal membrane did not intersect. In the remaining 19 pregnancies, there was a complete correlation between the findings at the ipsilon zone and transvaginal ultrasonography at 6-7 weeks. CONCLUSION: Ultrasonographic assessment of the ipsilon zone is useful for predicting chorionicity in triplet pregnancies.
High failure rate of postmortem karyotyping after termination for fetal abnormality.
OBJECTIVE: To determine the failure rate of karyotyping from samples taken after termination of pregnancy for fetal abnormality. METHODS: Perinatal autopsy reports over a 12-month period were reviewed to identify those with cytogenetic studies performed after termination of pregnancy for fetal abnormality. RESULTS: During the audit period, there were 104 terminations for fetal abnormality. In 89 fetuses, fetal skin (n = 85), placenta (n = 62), or other samples (n = 8) were obtained for postmortem cytogenetic analysis. In 24 (27%) fetuses, postmortem tissues did not yield a karyotype result. The failure rate of post-termination karyotyping was significantly influenced by delivery-sampling interval, but not by gestational age, type of tissue sampled, use of potassium chloride, or aneuploidy. Of the 24 cases for which no post-termination karyotype was obtained, 16 had had successful pre-termination karyotyping, resulting in only eight of 89 (9%) cases in the overall series not having a final karyotype. CONCLUSION: The high failure rate for post-termination karyotyping suggests that a pre-termination procedure is necessary if parents wish to have almost 100% certainty that cytogenetic information will be available for later genetic counseling.
Second-trimester echogenic bowel and intraamniotic bleeding: association between fetal bowel echogenicity and amniotic fluid spectrophotometry at 410 nm.
OBJECTIVE: Our purpose was to determine whether the presence of heme pigments in amniotic fluid is associated with the ultrasonographic findings of increased fetal bowel echogenicity in the second trimester. STUDY DESIGN: Spectrophotometric analysis of amniotic fluid for optical density at 410 nm was prospectively performed to study the presence of heme pigments in (1) 104 pregnancies undergoing second-trimester amniocentesis for routine cytogenetic indications and (2) in 14 pregnancies undergoing amniocentesis for prenatal karyotyping because of fetal strongly echogenic bowel. In the routine amniocentesis group the fetal small bowel echogenicity was assessed immediately before amniocentesis and classified as nonechogenic (n = 64), mildly echogenic (n = 36), or hyperechogenic (n = 4) with the fetal iliac wing and liver used as references. Only amniotic fluid specimens that were obtained at the first attempt and that were not blood-stained were included in this study, with the first milliliter being discarded in all samples. RESULTS: In the routine amniocentesis group abnormal amniotic fluid optical density readings were significantly more frequent in fetuses with increased bowel echogenicity compared with those with nonechogenic bowel (8/40 [20%] vs 3/64 [5%], respectively; p < 0.001). In the hyperchogenic bowel group abnormal amniotic fluid optical density readings were found in four samples (29%). Overall, 12 of 54 fetuses (22%) with increased bowel echogenicity had a detectable peak at 410 nm. Three of the 12 (25%) fetuses with echogenic bowel and positive readings for hemoglobin were chromosomally abnormal. CONCLUSIONS: Fetal small bowel echogenicity is associated with the presence of heme pigments in amniotic fluid as determined by amniotic fluid optical density at 410 nm. Swallowing of amniotic fluid after intraamniotic bleeding seems implicated in the etiology of second-trimester echogenic bowel in both euploid and aneuploid fetuses.
Hydrostatic and osmotic pressure gradients produce manifestations of fetofetal transfusion syndrome in a computerized model of monochorial twin pregnancy.
OBJECTIVE: In spite of recent advances in the assessment and treatment of fetofetal transfusion syndrome, its underlying mechanism remains controversial. We aimed to determine whether the clinical features of fetofetal transfusion syndrome could be explained by unidirectional or bidirectional intertwin transfusion along placental vascular anastomoses. STUDY DESIGN: We constructed a dynamic computerized model of monochorial twin fetoplacental units on the basis of numerous interrelated hemodynamic, osmotic, and metabolic physiologic variables. The circulations were then linked by various combinations of direction and number of arteriovenous anastomoses. RESULTS: With unidirectional anastomoses disease severity, characterized by disparity in blood solids, depended on donor arterial pressure but not on the number of anastomoses. In the chronic state water movement resulting from raised osmotic pressure in the recipient and reduction in the donor produced hydroosmotic pressure equilibrium, reducing anastomotic flow to near zero. Atrial natriuretic peptide-driven urine production was markedly increased in the recipient because of the raised vascular hydrostatic pressure component. With bidirectional anastomoses recirculation between twins reduced discordancy in colloids and hematocrit, and the clinical picture was determined by the degree of asymmetry in the number of connections. CONCLUSIONS: Severe manifestations of fetofetal transfusion syndrome can be explained by unidirectional intertwin transfusion and lesser degrees by asymmetric bidirectional transfusion.
Reverse end-diastolic flow in the middle cerebral artery: an agonal pattern in the human fetus.
Serial Doppler ultrasonography in a severely growth-restricted fetus revealed progressive reduction in pulsatility index of the middle cerebral artery, consistent with brain-sparing effect. At 29 weeks, 1 week before fetal death, the pulsatility index in the middle cerebral artery returned to normal values and became reversed the day before fetal death. This report suggests that reverse flow in the middle cerebral artery is one of the terminal hemodynamic events preceding fetal death.
Is isolated second-trimester hyperechogenic bowel a predictor of suboptimal fetal growth?
Hyperechogenic bowel has been described as a normal variant in second-trimester fetuses, but also in association with cystic fibrosis, chromosomal abnormalities, congenital infection, intestinal obstruction and intra-amniotic bleeding. These fetuses are also at risk for poor perinatal outcome, mainly due to intrauterine growth retardation. In this report we examine the potential of ultrasonographic detection of isolated fetal hyperechogenic bowel in the second trimester as a marker of subsequent suboptimal fetal growth. Second-trimester fetuses with hyperechogenic bowel in comparison to controls had a greater incidence of birth weight below the 10th centile (6/48, 12.5% vs. 4/149, 2.7%, respectively; p = 0.01) and lower mean birth weight (3176 g (SD 741 vs. 3499 g (SD 493)), respectively; p = 0.001). There was no difference in the prevalence of preterm delivery in both groups (3/48, 6.3% vs. 8/149, 5.4%, respectively; p = 0.7). This study suggests that second-trimester fetuses normally-grown with isolated hyperechogenic bowel are at risk for suboptimal fetal growth.
The lambda sign at 10-14 weeks of gestation as a predictor of chorionicity in twin pregnancies.
Chorionicity was prospectively determined in 369 twin pregnancies by ultrasound at 10-14 weeks of gestation. Pregnancies were classified as monochorionic if there was a single placental mass in the absence of the lambda sign at the inter-twin membrane-placental junction, and dichorionic if there was a single placental mass but the lambda sign was present, or the placentas were not adjacent to each other. In 81 (22%) cases, the pregnancies were classified as monochorionic and in 288 (78%) as dichorionic. Pregnancy outcome was available in 279 cases and all 63 of these pregnancies classified as monochorionic resulted in the delivery of same-sex twins. Similarly, all 100 different-sex pairs were correctly classified as dichorionic. These findings demonstrate the high reliability of ultrasound examination at 10-14 weeks of gestation in determining chorionicity in twin pregnancies.
Umbilical vein to artery ratio in fetuses with single umbilical artery.
In fetuses with single umbilical artery (SUA) the entire blood flow to the placenta is transported through only one umbilical artery, resulting in a compensatory increase of the arterial diameter. In order to establish whether umbilical vessel size could be used as an additional ultrasonographic criterion for prenatal diagnosis of SUA, we measured umbilical vein and umbilical artery diameters in 55 fetuses with SUA and in 55 with a normal three-vessel cord matched for gestational age. In all but one fetus with SUA, the diameter of the umbilical artery was greater than 50% of that of the umbilical vein, resulting in an umbilical vein to umbilical artery ratio of < or = 2. In contrast, none of the fetuses with a three-vessel cord had a ratio of < or = 2. Increasing diameter of the umbilical artery with no modification of the diameter of the vein is a characteristic prenatal ultrasonographic feature of SUA, making this observation a useful technique for the detection of this vascular anomaly in utero.
The lambda sign in twin pregnancies.
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Screening for trisomy 21 in twin pregnancies by maternal age and fetal nuchal translucency thickness at 10-14 weeks of gestation.
OBJECTIVE: To determine the prevalence of increased fetal nuchal translucency thickness in twin pregnancies and to evaluate screening for trisomy 21 by a combination of translucency thickness and maternal age. DESIGN: Prospective screening study at 10 to 14 weeks of gestation. SETTING: Fetal Medicine Centre. POPULATION: 22,518 self-selected pregnant women at 10 to 14 weeks of gestation, including 21,477 singleton and 448 twin pregnancies with live fetuses. METHODS: Fetal nuchal translucency thickness was measured by ultrasound examination at 10-14 weeks. Sensitivity and false positive rates of screening for trisomy 21 by a combination of fetal nuchal translucency thickness and maternal age were calculated. MAIN OUTCOME MEASURES: Prevalence of increased nuchal translucency thickness and detection of trisomy 21. RESULTS: In the 448 twin pregnancies the nuchal translucency thickness was above the 95th centile of the normal range (for crown-rump length in singletons) in 65/896 fetuses (7.3%), including 7/8 (88%) with trisomy 21. Increased translucency was also present in four fetuses with other chromosomal abnormalities. In the chromosomally normal twin pregnancies the prevalence of increased nuchal translucency was higher in fetuses from monochorionic (8.4%; 16/190) than in those with dichorionic pregnancies (5.4%; 37/688). The minimum estimated risk for trisomy 21, based on maternal age and fetal nuchal translucency thickness, was 1 in 300 in 19.5% (175/896) of the twins including all eight of those with trisomy 21. CONCLUSIONS: In twin pregnancies the sensitivity of fetal nuchal translucency thickness in screening for trisomy 21 is similar to that in singleton pregnancies, but the specificity is lower because translucency is also increased in chromosomally normal monochorionic twin pregnancies.
Fetal telemedicine: six month pilot of real-time ultrasound and video consultation between the Isle of Wight and London.
DESIGN: Prospective audit of first six months. SETTING: Referral from a district general hospital on the Isle of Wight to a comprehensive tertiary referral service, the Centre for Fetal Care at Queen Charlotte's Hospital 120 km away in London. PARTICIPANTS: Women whose pregnancy was suspected, or at risk, of fetal abnormality. INTERVENTIONS: Remote consultation by transmitting ultrasound and video in real-time over ISDN 30 telephone lines. Contemporaneous questionnaire to referring practitioner and patient. MAIN OUTCOME MEASURES: Frequency, indication, technical success and duration of consultation. Qualitative and semi-quantitative image quality. Effect of teleconsultation on need for physical referral. RESULTS: Twenty-nine women underwent 39 teleconsultations, and image quality was sufficient for diagnosis in all but one. Fetal abnormalities were present in 76%. Referral in person was required for only four women, significantly fewer than the 13 the referring hospital indicated would have been physically referred in the absence of this service (P < 0.001). Most mothers were counselled by the specialist "face-to-face' over the link, and 80% felt teleconsultation reduced their anxiety. CONCLUSIONS: A fetal telemedicine service is technically and clinically feasible. This demonstration suggests that such a service reduces the need for physical referral while increasing the rate of consultation, allowing better selection of patients who might benefit from referral. Further evaluation in a variety of clinical settings is now indicated, along with cost-benefit analysis.
Vasa praevia: second trimester diagnosis using colour flow imaging.
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