Vasa previa in singleton pregnancies: diagnosis and clinical management based on an international expert consensus.

BACKGROUND: There are limited data to guide the diagnosis and management of vasa previa. Currently, what is known is largely based on case reports or series and cohort studies. OBJECTIVE: This study aimed to systematically collect and classify expert opinions and achieve consensus on the diagnosis and clinical management of vasa previa using focus group discussions and a Delphi technique. STUDY DESIGN: A 4-round focus group discussion and a 3-round Delphi survey of an international panel of experts on vasa previa were conducted. Experts were selected on the basis of their publication record on vasa previa. First, we convened a focus group discussion panel of 20 experts and agreed on which issues were unresolved in the diagnosis and management of vasa previa. A 3-round anonymous electronic survey was then sent to the full expert panel. Survey questions were presented on the diagnosis and management of vasa previa, which the experts were asked to rate on a 5-point Likert scale (from "strongly disagree"=1 to "strongly agree"=5). Consensus was defined as a median score of 5. Following responses to each round, any statements that had median scores of ≤3 were deemed to have had no consensus and were excluded. Statements with a median score of 4 were revised and re-presented to the experts in the next round. Consensus and nonconsensus statements were then aggregated. RESULTS: A total of 68 international experts were invited to participate in the study, of which 57 participated. Experts were from 13 countries on 5 continents and have contributed to >80% of published cohort studies on vasa previa, as well as national and international society guidelines. Completion rates were 84%, 93%, and 91% for the first, second, and third rounds, respectively, and 71% completed all 3 rounds. The panel reached a consensus on 26 statements regarding the diagnosis and key points of management of vasa previa, including the following: (1) although there is no agreement on the distance between the fetal vessels and the cervical internal os to define vasa previa, the definition should not be limited to a 2-cm distance; (2) all pregnancies should be screened for vasa previa with routine examination for placental cord insertion and a color Doppler sweep of the region over the cervix at the second-trimester anatomy scan; (3) when a low-lying placenta or placenta previa is found in the second trimester, a transvaginal ultrasound with Doppler should be performed at approximately 32 weeks to rule out vasa previa; (4) outpatient management of asymptomatic patients without risk factors for preterm birth is reasonable; (5) asymptomatic patients with vasa previa should be delivered by scheduled cesarean delivery between 35 and 37 weeks of gestation; and (6) there was no agreement on routine hospitalization, avoidance of intercourse, or use of 3-dimensional ultrasound for diagnosis of vasa previa. CONCLUSION: Through focus group discussion and a Delphi process, an international expert panel reached consensus on the definition, screening, clinical management, and timing of delivery in vasa previa, which could inform the development of new clinical guidelines.

Systematic screening for vasa previa at the 20-week anomaly scan.

INTRODUCTION: The presence of vasa previa carries a high risk for severe fetal morbidity and mortality due to fetal bleeding caused by injury to unprotected fetal vessels when rupture of membranes occurs. Previously, it has been shown that prenatal diagnosis significantly improves the outcome. However, systematic screening for vasa previa is not generally performed and clinical studies demonstrating the performance of systematic screening for vasa previa in routine clinical practice are rare. The objective of this study was to assess the performance of systematic screening for vasa previa by determining placental cord insertion at the 20-week anomaly scan. MATERIAL AND METHODS: This is a retrospective study of 6038 pregnant women between 18+0 and 24+0 gestational weeks who were prospectively screened for vasa previa by depiction of the site of placental cord insertion at the 20-week anomaly scan. Pregnancies with marginal or velamentous cord insertion underwent vaginal sonography for examination for vasa previa. In cases with succenturiate or bilobed placentas, the bridging vessels were depicted, and vaginal sonography was performed if necessary. RESULTS: There were 21 cases of vasa previa and all were diagnosed prenatally. In 18 cases, the cord insertion was marginal or velamentous. The remaining three cases had placental anomalies, which necessitated a detailed examination. All pregnancies with vasa previa were delivered at a mean of 35.2 (SD 1.8) gestational weeks by cesarean section. Among pregnancies affected by vasa previa, all fetuses survived. The median birthweight was 2390 g (range 1200-2990 g) and the mean umbilical artery pH 7.34 (SD 0.04). The median 5-min APGAR score was nine (range 7-10). None of the fetuses or neonates died or required blood transfusions. In all pregnancies of the whole cohort which were complicated by fetal or neonatal demise and in neonates with a 5-min APGAR score ≤5 and/or an umbilical artery pH ≤7.10, fetal blood loss was excluded as a cause of the poor obstetric outcome. CONCLUSIONS: Screening for vasa previa is feasible and efficient, taking into account the site of placental cord insertion in pregnancies not affected by placenta previa and bilobed and succenturiate placenta.

Screening for Open Spina Bifida in a Routine Clinical Setting at the First-Trimester Scan: A Prospective Multicentre Cohort Study.

OBJECTIVE: The aim of this study was to investigate the performance of screening for open spina bifida (OSB) integrated into the routine first-trimester screening. METHOD: This is a prospective multicentre study of 4,755 women undergoing first-trimester ultrasound scans over a 4-year period. Measurements of the brainstem (BS) diameter and brainstem-to-occipital-bone (BSOB) distance were performed. The cisterna magna (CM) was measured in the tilted axial view. RESULTS: Pregnancy outcome data were available for 4,658 fetuses included in this study. There were 5 fetuses with OSB, and in all of them, the BS/BSOB ratio and the CM measurements were abnormal. The sensitivity and specificity of a BS/BSOB ratio >1 were 100%. The sensitivity of a CM width <5th centile was 100%, and the specificity was 95.1%. In 4.6% of cases, the BS/BSOB ratio was between the 95th percentile and 1. In 87.1% of these cases, the CM was normal, and 12.9% had a CM below the 5th percentile. CONCLUSION: Screening for OSB is feasible in routine first-trimester scans. The BS/BSOB ratio shows a very good sensitivity and specificity. In cases with near-normal values for the BS/BSOB ratio, the CM width might be helpful for further assessment.

Diagnosis of Fetal Posterior Fossa Malformations in High-Risk Pregnancies at 12-14 Gestational Weeks by Transvaginal Ultrasound Examination.

OBJECTIVE: To demonstrate sonographic detectable abnormalities of the posterior fossa in fetuses with a crown-rump length of 45-84 mm in high-risk pregnancies. METHODS: This was a prospective, observational study including 47 fetuses with known outcome, whose mothers attended our centers for first trimester tests and showed an abnormal first trimester ultrasound scan. In these fetuses, we examined transvaginal acquired three-dimensional volume blocks for abnormalities of the fetal posterior fossa. In these fetuses, the measurements of the cerebellar vermis (VE) and of the anterior membranous area (AMA) were compared with published reference ranges. RESULTS: There were 8 fetuses with a ver-mian length below the 5th centile. In 5 of these fetuses, the AMA was also elongated and in 4 of these fetuses, pathology was confirmed. One case with a normal vermian length and normal AMA had a hypoplastic VE later on in the confirmatory test. CONCLUSION: Pathology of the posterior fossa can be directly diagnosed by assessing the VE and the AMA at the first trimester scan by examining transvaginal acquired volume blocks.

Cranial sonographic markers of fetal open spina bifida at 11 to 13 weeks of gestation.

OBJECTIVES: To compare the sonographic signs of spina bifida obtained on axial and sagittal views of the fetal head between 11 and 13+6 weeks of gestation. METHODS: This was a retrospective study including 27 cases of spina bifida and 1003 randomly selected controls. Indirect markers of spina bifida were evaluated on stored ultrasound images. Intracranial translucency (IT), ratio between the brainstem and the brainstem-occipital bone distance (BS/BSOB), and maxillo-occipital (MO) line were assessed on sagittal view, whereas biparietal diameter (BPD), BPD to abdominal circumference ratio (BPD/AC), and aqueduct to occipital bone (aqueduct of Sylvius [AoS]) distance were measured on the axial plane. Reference ranges were developed, and cases of spina bifida were examined in relation to the reference range. RESULTS: On the sagittal view, detection rates for IT below the fifth percentile, BS/BSOB above the 95th percentile, and an abnormal MO line were 52.3%, 96.3%, and 96.3%, respectively. On the axial view, detection rates for BPD, BPD/AC, and AoS below the fifth percentile were 66.7%, 70.4%, and 77.8%, respectively. CONCLUSION: The MO line and the BS/BSOB ratio appear to be the best indirect ultrasound markers of spina bifida and can be easily obtained during the routine first-trimester scan.

Reference Ranges for Transvaginal Examined Fossa Posterior Structures in Fetuses from 45 to 84 mm Crown-Rump Length.

OBJECTIVE: The study aimed to describe reference values for structures of the posterior fossa in fetuses with a crown-rump length (CRL) between 45 and 84 mm. MATERIALS AND METHODS: This was a prospective, cross-sectional study including 216 normal appearing fetuses. In transvaginal acquired 3-dimensional volume blocks, the longest diameter of the vermis (VE), posterior membranous area (PMA), medulla-oblongata-pons angle (MOPA), diameters of the medulla oblongata (MO) and pons (PO), and the area of Blake's pouch (BP) were measured. Polynomial or linear regression analysis were performed to calculate the mean, 5th and 95th centile according to CRL. In 20 fetuses, intra- and interobserver repeatability were calculated. RESULTS: There is a curvilinear correlation between CRL and PO (PO [mean] = 1.3893 + 0.004356 × CRL + 0.000002610 × CRL3; SD = 1.6818 - 0.03765 × CRL + 0.000003831 × CRL3; R2 = 0.489); CRL and MO (MO [mean] = 1.5959-0.001905 × CRL + 0.000003362*CRL3; SD = -0.1417 + 0.005404 × CRL + 0.0000004988 × CRL3; R2 = 0.525); CRL and VE (VE [mean] = -0.3640 + 0.04302 × CRL+ 0.000001486 × CRL3; SD = 0.5854 - 0.004812 × CRL + 0.0000005896 × CRL3; R2 = 0.643); CRL and PMA (PMA [mean] = 0.6901 + 0.04307 × CRL - 0.0000008459 × CRL3; SD = -0.4232 + 0.02026 × CRL - 0.000001320 × CRL3; R2 = 0.272); CRL and BP (mm2; BP [mean] -12.2067 + 0.3334 × CRL - 0.00001262 × CRL3; SD = -1.6431 + 0.06380 × CRL+ 0.0000003257 × CRL3; R2 = 0.289). The relation between CRL and MOPA (°) is best described by a linear regression (MOPA [mean] = 79.6332 + 0.6122 × CRL; SD = 4.8453 + 0.07333 × CRL; R2 = 0.318). CONCLUSION: We provide reference values for anatomical structures of the posterior fossa of fetuses between 45 and 84 mm CRL. The established reference values might ease the diagnosis of fetal malformations in early pregnancy.

Sonoembryology of the fetal posterior fossa at 11 + 3 to 13 + 6 gestational weeks on three-dimensional transvaginal ultrasound.

OBJECTIVE: To describe the sonographic appearance and temporal changes of the structures of the posterior cranial fossa in fetuses at a crown-rump length (CRL) between 45 and 84 mm in transvaginal acquired three-dimensional volume blocks. METHODS: This was a prospective, cross-sectional, observational study including 80 fetuses, whose mothers attended Kepler University Hospital Linz or the Ambulatorium für Fetalmedizin Feldkirch for first-trimester sonography. Three-dimensional volume blocks were acquired in a standardized way and after processing the sonographic characteristics of the brainstem, cerebellar vermis, choroid plexus, anterior membranous area (AMA) and Blake's metapore were described. Measurements of the length of the cerebellar vermis, the length of the AMA and the medulla-oblongata-pons angle (MOPA) were performed. In 20 fetuses the intra- and interobserver repeatability was calculated. RESULTS: The sonomorphologic characteristics of posterior fossa structures as cerebellar vermis, AMA, Blake's metapore, choroid plexus, pons and medulla oblongata were described. There is a significant correlation between CRL and vermis length, CRL and MOPA and CRL and AMA. CONCLUSIONS: Transvaginal three-dimensional sonography allows a detailed depiction of the structures of the posterior fossa and their temporal course in early pregnancy. © 2016 John Wiley & Sons, Ltd.

Prenatal sonographic diagnosis of intrahepatic portosystemic shunts.

The incidence of fetal portosystemic anastomoses is unknown, and it is presumed that many cases remain undetected, as visualization of the hepatic vasculature is not part of the routine 20-week sonographic scan in pregnancy. However, portosystemic anastomoses are associated with fetal growth restriction due to a diminished oxygen supply to hepatocytes and, hence, downregulation of liver function. In these cases, uteroplacental perfusion might be normal.

Doppler evaluation of the posterior cerebral artery in normally grown and growth restricted fetuses.

OBJECTIVE: To evaluate Doppler parameters of the two segments of the posterior cerebral artery (PCA) in normally grown and growth restricted (IUGR) fetuses. METHODS: Normal reference values of the pulsatility index (PI), peak systolic velocity, end-diastolic velocity, and time-averaged maximum velocity from the two segments of the PCA (segment one, PCA-S1; segment two, PCA-S2) were constructed in 350 pregnant women from 20 to 40 weeks of gestation. The association of the two PCA segments with the middle cerebral artery (MCA), and with the umbilical artery was evaluated in 50 IUGR fetuses. RESULTS: In normal fetuses, Doppler parameters from PCA-S1 and PCA-S2 showed similar behavior throughout gestation. In IUGR fetuses, the PI of the two PCA segments was significantly reduced with no differences between them. PCA-S2 PI showed a higher correlation with the MCA-PI (r = 0.73) than PCA-S1 PI (r = 0.63; p = 0.001). IUGR fetuses showed vasodilatation in the PCA earlier than in the MCA disregarding the umbilical artery-PI value. CONCLUSION: In IUGR fetuses, the two segments of the PCA show signs of vasodilatation earlier than the MCA. As IUGR fetuses deteriorate, the two segments of the PCA and the MCA behave similarly.

Perinatal mortality and advanced maternal age.

OBJECTIVE: To investigate the impact of advanced maternal age on the rate of perinatal mortality. DESIGN: Retrospective cohort study including all 56,517 singleton hospital deliveries between 1999 and 2008. METHODS: Data were analyzed according to maternal age at delivery in 3 groups of women, 25-34 years, 35-39 years and ≥ 40 years, using the youngest as the reference group. RESULTS: Odds ratios (ORs) for antenatal deaths were 0.98 (CI: 0.67-1.43) and 2.57 (CI: 1.57-4.22) for age groups 35-39 years and ≥ 40 years, respectively. Significant differences in neonatal mortality rates between the age groups were not found. Significant amendable risk factors were attendance of <4 health care visits (OR = 15.55, CI: 9.47-25.51 in age group 35-39 years; OR = 16.38, CI: 9.78-27.43 in the age group ≥ 40 years) and obesity (OR = 1.85, CI: 1.27-2.70 in age group 35-39 years; OR = 1.83, CI: 1.22-2.74 in the age group ≥ 40 years). In the multivariate regression analysis, the adjusted ORs for perinatal mortality were 1.03 (95% CI: 0.77-1.39) and 1.66 (95% CI: 1.03-2.66) for age groups 35-39 and ≥ 40, respectively. CONCLUSIONS: Women older than 40 years carry an increased risk for stillbirth. Important amendable risk factors are obesity and poor antenatal care.

Outcome of twin reversed arterial perfusion sequence following treatment with interstitial laser: a retrospective study.

OBJECTIVES: To determine the outcome of twin reversed arterial perfusion (TRAP) sequence treated with or scheduled for treatment with interstitial laser therapy. METHODS: This is a retrospective study on ten pregnancies diagnosed with TRAP sequence. Seven of the ten pregnancies were treated with interstitial laser therapy, and two pregnancies were scheduled for later treatment. One pregnancy was treated with fetoscopic laser ablation and excluded from analysis. The delivery reports of all pregnancies were collected, the neonatal health status recorded and the median time of delivery and the treatment to delivery interval calculated. RESULTS: Six of seven pump fetuses in TRAP pregnancies treated with interstitial laser therapy at a median of 16+2 (range 13+1 to 20+3) gestational weeks were born healthy at a median of 38+0 (range 34+3 to 40+6) gestational weeks. One fetus treated with interstitial laser died after the procedure at 20+3 weeks. Two pump twins scheduled for later treatment died before the gestational age of 16 weeks. The median treatment to delivery interval for the surviving fetuses was 153 days (range 128-194). CONCLUSION: Treatment of TRAP sequence by interstitial laser therapy is feasible from the 13th week of gestation and has a good outcome.

Changes in central and peripheral circulation in intrauterine growth-restricted fetuses at different stages of umbilical artery flow deterioration: new fetal cardiac and brain parameters.

OBJECTIVE: To evaluate changes in central and peripheral circulation, including new and standard parameters of the fetal brain and heart in fetuses with intrauterine growth restriction (IUGR) in relation to progressive deterioration of the umbilical artery (UA). METHODS: Seventy-two IUGR fetuses were studied longitudinally. IUGR was defined as an estimated fetal weight <10th centile for gestational age. Fetuses were classified according the UA pulsatility index (PI) as: group 1, normal UA-PI (<95th centile; <1.645 z-scores), group 2, UA-PI (≥95th centile and <99th centile; ≥1.645 and <3 z-scores), group 3, UA absent end-diastolic flow, and group 4, UA reversed end-diastolic flow. Middle cerebral artery (MCA), anterior cerebral artery segments 1 (ACA1) and 2 (ACA2), aortic isthmus blood flow index (IFI), modified myocardial performance index (Mod-MPI), ductus venosus (DV), renal artery (RA), femoral artery (FA) and amniotic fluid index (AFI) were weekly evaluated until delivery. RESULTS: A total of 263 scans were performed (median, 3 (range: 1-23) per patient). There were 6 intrauterine and 2 neonatal deaths. Although all cerebral arteries showed a reduction in the PI, ACA1 showed the earliest vasodilatation. From group 2 onwards, all cerebral vessels had a similar pattern of vasodilatation. Mod-MPI became abnormal at group 1 with no further changes. IFI and DV became constantly abnormal starting from group 2. No changes in the RA-PI or FA-PI were documented. CONCLUSION: The process of hemodynamic deterioration in IUGR fetuses seems to be earlier represented by the ACA1 and the Mod-MPI. Signs of further deterioration were observed in the DV, IFI and MCA. The peripheral blood in the RA and FA did not show any change. AFI showed a late deterioration process.

Oxygen utilization in newborns at delivery.

AIMS: To evaluate the arteriovenous (AV) pH difference in cord blood as a possible indicator of fetal O(2)-utilization at delivery. Furthermore to examine which maternal, fetal and obstetrical factors lead to elevated O(2)-utilization. METHODS: In this retrospective study all singleton live births, delivered within a four-month period at the University Hospital in Innsbruck, Austria, were analyzed. In total 491 deliveries were evaluated. Arterial and venous cord blood samples were collected at birth and analyzed by using a Radiometer ABL 510. RESULTS: Spontaneous deliveries showed a highly significant elevation in AV-difference (pH 0.10) as compared to cesarean sections (pH 0.05). In spontaneous births, the AV-difference was high in the case of low arterial cord blood pH (P<0.01), as well as in nuchal cord (P<0.01), high parity (P<0.01), very short labor (P<0.05) and elevated birth size and weight (P<0.05). CONCLUSIONS: As a result of increased fetal stress at birth, spontaneous delivery leads to higher O(2)-utilization than cesarean section, which is detectable in an elevated AV-difference. The AV-difference in combination with absolute pH-values can be used for the objective evaluation of fetal O(2)-utilization and consecutively the fetal stress at birth.

Congenital fibrosarcoma as cause for fetal anemia: prenatal diagnosis and in utero treatment.

OBJECTIVES: To discuss diagnosis and management of a case of a rare fetal tumor complicated by fetal anemia due to intratumoral hemorrhage. CASE REPORT: We report on a 29-week-old fetus with a tumor in the posterior left shoulder region. The morphologic aspect of the tumor, lack of fetal movements and an increased middle cerebral artery (MCA) peak systolic velocity (PSV) were indicative of fetal anemia caused by intratumoral bleeding. Following intravascular blood transfusion the pregnancy was safely prolonged for 15 days, during which lung maturity was induced. After delivery the neonate underwent surgical excision. Histological examination revealed an infantile congenital fibrosarcoma. CONCLUSION: Anemia must be ruled out in cases with fetal tumors. MCA PSV is useful in diagnosis and surveillance in these fetuses.

Prediction of severe fetal anemia in red blood cell alloimmunization after previous intrauterine transfusions.

OBJECTIVE: This study was undertaken to determine the detection of fetal anemia and false-positive rates by fetal middle cerebral artery peak systolic velocity (MCA-PSV) and the estimated daily decrease of hemoglobin (Hb) in red blood cell alloimmunized pregnancies that had previous fetal transfusions. STUDY DESIGN: We examined the relation between MCA-PSV measured before cordocentesis, and fetal Hb at the time of the second (n = 42) and third (n = 31) intrauterine blood transfusions. In addition, the daily Hb drop between the transfusions was calculated. RESULTS: The MCA-PSV provided significant prediction of severe anemia (Hb deficit > or = 6 g/dL) for the second but not for the third transfusion. Detection of 95% of severely anemic fetuses was achieved with a false-positive rate of 37% for the second transfusion and 90% for the third, compared with 14% in our previous study for the first transfusion. In patients who had received 2 previous transfusions, the only significant predictor of fetal anemia was the estimation of the Hb from the measured posttransfusion Hb after the second transfusion and the assumption that the rate of decrease in fetal Hb is 0.3 g/dL per day. CONCLUSION: Prediction of severe fetal anemia after one transfusion is less accurate than in nontransfused fetuses. The MCA-PSV is not useful in predicting severe anemia in fetuses that already had 2 previous transfusions.