Vasa Previa Research Articles

Vasa previa, too often a fatal presentation of intrapartum bleeding and fetal distress

Vasa previa, too often a fatal presentation of intrapartum bleeding and fetal distress

The association of abnormal α-fetoprotein and adverse pregnancy outcome: Does increased fetal surveillance affect pregnancy outcome?

Objective: Our purpose was to investigate whether adverse outcomes associated with elevated maternal serum α-fetoprotein levels may be prevented by intensive antenatal monitoring. Study Design: Records of patients with elevated maternal serum α-fetoprotein values of ≥2.0 multiples of the median between 1995 and 1999 were reviewed. Pregnancy histories were analyzed to determine whether intensive antenatal monitoring (twice-weekly nonstress tests and determinations of the amniotic fluid index) would have detected the adverse outcomes when routine obstetric care would have missed them. Women with elevations explained by multiple gestations, structural abnormalities, or a fetal death were excluded. Results: The study enrolled 136 patients. Twenty-three patients were excluded because of multiple gestations, structural or chromosomal abnormalities, or fetal death or for lack of available follow-up. Seventy-eight patients had no perinatal complications, but 12 of these patients underwent heightened surveillance. One of these patients was subjected to an induction of labor. Thirty-five pregnancies had complications (21 with preterm labor, 7 with pregnancy-induced hypertension, 6 with growth restriction or oligohydramnios, 1 with abruptio placentae, and 1 with vasa previa). Of these 35 pregnancies, 22 were followed up with routine obstetric care and 13 with heightened surveillance. Heightened surveillance did not achieve earlier or improved detection in this group. These results suggest that routine pregnancy management is an adequate strategy for providing care to pregnant patients with unexplained elevated maternal serum α-fetoprotein levels. Adverse outcomes were detected with routine pregnancy management or were undetectable even with intensive management. Conclusion: Increased risks of pregnancy-induced hypertension, preterm delivery, intrauterine growth restriction, intrauterine fetal death, oligohydramnios, and abruptio placentae are associated with elevated maternal serum α-fetoprotein levels. However, in our study, routine pregnancy management was an acceptable method of detecting these adverse outcomes when they were detectable. (Am J Obstet Gynecol 2001;184:1549-55.)

Prenatal Diagnosis of a Velamentous Cord Insertion Associated With a Vasa Previa

A vasa previa is associated with very high fetal mortality rates and is often not detected until catastrophic events occur. As was the case discussed in this report, a vasa previa is often associated with a velamentous insertion of the umbilical cord. In most cases, an abnormal insertion of the umbilical cord is not made until the placenta and the amniotic membranes are examined following delivery. Utilizing both gray-scale and color Doppler sonography, it is possible to diagnose both these conditions prenatally in order to provide clinical information pertinent to subsequent fetal outcome.

F76Patients undergoing three‐dimensional ultrasound: review of referrals for 111 patients

BackgroundThree‐dimensional ultrasound (3DUS) is a rapidly emerging imaging technology offering improved visualization of patient anatomy. The purpose of this project was to identify the distribution of patients referred for 3DUS on a clinical service and assess the potential impact on care and management strategies.MethodCharts from 111 patients having 3DUS studies in our clinical obstetrical and gynecological service were reviewed for indications. Patients were categorized as:1) 3DUS specific referrals based on 2DUS findings, 2) value added DUS studies to2) trouble shoot problems identified with 2DUS, 3) physician requested 3DUS studies to enhance patient reassurance and 4) patient initiated 3DUS studies for reassurance.ResultsIndication for 3DUS studies were: 3DUS specific referrals (30) (e.g. facial anomalies, sonohysterogams), trouble shoot problems identified with 2DUS (45) (e.g. club feet, vasa previa), physician requested studies to enhance patient reassurance (e.g. prior anomalies) and patient initiated 3DUS for reassurance (15) (e.g. prior anomalies, surrogate parents, hospice patients). Availability of 3DUS imaging resulted in new models of patient referral (internet, patient initiated, distant to the community).ConclusionAs new technology (e.g. 3DUS) enters the clinical arena, new pathways for patients to access technology develop (outside referrals, patient referrals, internet).Improved information alters and improves patient responses (comprehension, decision making, reassurance) to their medical situation.

Outcome of pregnancies with vasa previa

Outcome of pregnancies with vasa previa

Antenatal diagnosis of velamentous umbilical cord insertion and vasa previa with color Doppler imaging.

To determine whether cord insertion can be consistently visualized and whether velamentous cord insertion and vasa previa can be consistently identified with color Doppler imaging during routine sonography in the mid-trimester. A prospective study. A total of 587 fetuses at 18-20 weeks' gestation. During routine ultrasound examinations, the sonographer was instructed to take additional time and to image the placental cord insertion with color Doppler imaging and classify this as normal, velamentous or 'not seen'. When the insertion was velamentous, the sonographer was instructed to indicate whether or not it was vasa previa. The sonogram obtained at 18-20 weeks' gestation was used for comparison with outcome data. Cord insertion was visualized by color Doppler imaging in 99.8% (586/587) of the fetuses in our study. The mean time required for examination was 20 s and, in 95% of the cases, cord insertion was visualized within 1 min. The sonographic identification of velamentous cord insertion had a sensitivity of 100% (5/5), a specificity of 99.8% (580/581), a positive predictive value of 83% (5/6) and a negative predictive value of 100% (580/580). In our study, vasa previa was diagnosed at 18 gestational weeks in two cases and, in one of the cases, vasa previa was confirmed at delivery. We could consistently identify cord insertion and velamentous cord insertion with color Doppler imaging during routine sonography in the mid-trimester. Transvaginal color Doppler imaging and serial scans were needed to identify vasa previa.

Risk Factors for Adverse Outcome in Peripartum Hemorrhagic Shock (HS). 1032

Rationale: Data in the perinatal animal and adult trauma patient suggest that the timing and severity of blood volume (BV) loss and rapidity and degree of BV replacement are important determinants of outcome in HS. Objective: To identify and analyze the importance of risk factors for adverse outcome. Methods: Retrospective data collection on 34 cases admitted from 1985-1994 (HSC) and 10 cases from 1988-1994 (MSH, WCH). Inclusion criteria: ≥34 wks gestation and HS at birth defined as severe pallor with reduced or absent pulses despite a HR of >100 bpm and a calculated BV loss of >25% (21 mls/kg). Exclusions: internal hemorrhage, chronic blood loss, or hemolysis. Adverse outcome included death or survival with severe neurological disability. Univariate analyses compared groups by adverse or good outcome. Results: Are expressed as median values(interquartile range). GA was 40 (37-40) wks, BW 3135 (2707-3535) g and the calculated BV loss was 48 (39-57) mls/kg. Five patients were lost to follow up and 19 of 39 (49%) had adverse outcomes: 11 died, 6 had severe CP and 2 had severe cognitive delay. Etiology of HS (cases with adverse outcome/total) included: placental abruption (5/14), fetomaternal hemorrhage (3/5), vasa praevia (4/4), umbilical cord tears (2/2), twin-to-twin transfusion (2/2), placenta praevia (1/2), tight nuchal cord (0/2), placental incision (0/2) and indeterminate (2/10). Group differences in Obstetrical factors (presence and timing of CTG abnormalities, occurrence of APH), and volume and timing of BV replacement were not statistically significant. Patients with adverse outcomes had greater blood losses of 54 vs. 44 mls/kg (p=0.03), a lower 5 minute Apgar score of 1 vs. 4 (p=0.006), greater base deficit of 21 vs. 12 mmol/l(p=0.006), and tended to have a longer interval from onset of HS to first volume replacement of 410 vs. 106 mins (p=0.19). Severe encephalopathy, seizures, DIC, myocardial ischemia, and severe renal dysfunction were strongly associated with adverse outcomes. Conclusions: Risk factors for adverse outcome included the magnitude of blood loss, severity of metabolic acidosis and depression at birth, and the presence of severe organ dysfunction. Length of time from onset of HS to first volume replacement, although not statistically significant, is likely to be a risk factor for adverse outcome.

Prenatal ultrasonographic morphologic assessment of the umbilical cord: a review. Part II.

Ultrasonographic assessment, although not always possible throughout the entire length of the umbilical cord, may assist in the diagnosis of congenital and functional anomalies of this structure. In such fashion, prenatal ultrasound may outline normal anatomy or alternatively depict various congenital abnormalities of the umbilical cord including: cysts; pseudocysts umbilical vein varix; persistent right umbilical vein; angiomyxomas; aneurysm (arterial or venous); single, hypoplastic or fused umbilical artery; hematomas (spontaneous or iatrogenic); velamentous insertion; vasa previa. The umbilical cord coiling index, an additional ultrasonographic morphologic feature, may identify patients at risk for adverse perinatal outcome. Conditions of potential fetal compromise due to umbilical cord compression including nuchal cords, true knots, occult prolapse, cord presentation, fetal grasping, and cord entanglement in monoamniotic twins, may be detected prenatally; and impaired umbilical flow can be confirmed with Doppler flow velocimetry. Ultrasound has been widely used to guide invasive diagnostic and therapeutic procedures involving access to umbilical circulation. We conclude that the review of current literature supports that precise prenatal ultrasonographic depiction of the morphology of the umbilical cord may enhance perinatal management.

Prenatal diagnosis of vasa praevia: the impact of colour flow imaging

Prenatal diagnosis of vasa praevia: the impact of colour flow imaging

Intrapartum Haemorrhage due to Idiopathic Rupture of the Fetal Placental Artery

EDITORIAL COMMENT: We accepted this interesting case report to remind readers that cardiotocography may identify fetal distress and the need for immediate delivery in women with intrapartum haemorrhage, which in this case resulted from fetal haemorrhage. May we also remind readers that a fetal origin should be considered in all cases of intrapartum blood loss since an abnormal cardiotocograph can be a late (too late!) sign from a fetus bleeding to death. Since fetal haemoglobin is resistant to alkali denaturation, a sample of blood from the vagina, diluted in water, will remain pink on the addition of 10% sodium hydroxide if fetal in origin, whereas it will turn brown if maternal (Apt test). A bottle of 10% sodium hydroxide should be available in every delivery suite so that this test can be performed when indicated; this is very often since how else can an ‘excessive show’ be distinguished from haemorrhage from a vasa praevia? The solution has a shelf‐life of only 1 month; a time‐expired solution may fail to turn maternal blood brown and thus give a false positive test for fetal blood.

Ultrasound of the Placenta and Membranes

Normal development and imaging characteristics of the placenta and membranes are discussed. Commonly observed placenta abnormalities are reviewed including placenta previa, abruption, placenta accreta, macroscopic lesions, primary neoplasms, and developmental variations, i.e. succenturiate lobes/ placenta membranacea. The umbilical cord and membranes are discussed in the second portion of this article with emphasis on two-vessel cords, umbilical cord masses, and amniotic sheets. Some of the newer sonographic techniques (translabial and transvaginal scanning) have led to improved diagnostic accuracy in several placental, uterine, and fetal conditions, and those approaches are discussed in this article, primarily with respect to placenta previa. Color and duplex Doppler sonography can often be used to increase the sonologist's confidence in a diagnosis and narrow the list of possibilities. Additionally. Doppler sonography may be helpful to improve sonographic sensitivity in the difficult diagnoses of placenta accreta or vasa previa.

A non-hemorrhagic manifestation of vasa previa: A clinicopathologic case report

A non-hemorrhagic manifestation of vasa previa: A clinicopathologic case report

Fetal Death Due to Spontaneous Rupture of Vasa Praevia with Intact Membranes

Fetal Death Due to Spontaneous Rupture of Vasa Praevia with Intact Membranes

Color flow Doppler-A useful instrument in the diagnosis of vasa previa

Vasa previa is associated with an increased perinatal mortality rate and rarely is diagnosed in the antepartum period. We present a case in which vasa previa was correctly diagnosed by use of color flow Doppler imaging. This modality is a valuable adjunct in the evaluation of patients suspected to have vasa previa. (Am J Obstet Gynecol 1990;163:1566-8.)

Sinusoidal fetal heart rate pattern associated with the twin to twin transfusion syndrome

Sinusoidal fetal heart rate pattern (FHR) is regarded by most authors as signifying a compromised fetus. In most cases, this is secondary to fetal anemia of different causes, usually Rh isoimmunization, more rarely to fetomaternal transfusion, bleeding vasa previa, placental chorioangioma, or traumatic amniocentesis. A case is described which to our knowledge is the first reported of a sinusoidal FHR pattern occurring in the relatively anemic donor twin in a case of the twin to twin transfusion syndrome. The importance of separate antepartum biophysical evaluation of each member of a twin pregnancy is emphasized.

Vasa Praevia—Report of Three Cases and Review of Literature

Vasa Praevia—Report of Three Cases and Review of Literature

Antepartum testing for vasa previa: Current standard of care

Vasa previa is a rare accident in obstetrics with high fetal mortality. There are simple tests available to distinguish fetal from maternal blood. Recently it has been called into medicolegal question whether patients with third-trimester bleeding need to be tested for fetal bleeding. We surveyed 100 community hospitals and all the medical schools in the United States in an attempt to answer the question. It appears that the standard of care in the United States does not require such testing.

Morphological anomalies in the placentae of IVF pregnancies: preliminary report of a multicentric study.

Macroscopic characteristics of 100 fetal adnexae from pregnancies obtained by in-vitro fertilization and embryo transfer (IVF-ET) were compared with data for normal pregnancies taken from the literature. Material was obtained from 63 singleton, 15 twin, one triplet and one quadruplet pregnancies. The fetal and placental weights as well as the fetal:placental weight ratio were within the normal range for gestational age. Whilst placental morphology was normal, the insertion of the umbilical cord was frequently abnormal. Marginal (15%) and velamentous (14%) insertions of the umbilical cord were found more frequently than in a general obstetrical population (6% and 1% respectively). Excluding placentae from multiple pregnancies (which are known to have a higher incidence of abnormal cord insertion) the frequency did not decrease and remained significantly higher than in a normal population (P less than 0.01 and P less than 0.001, for marginal and velamentous insertion respectively). Abnormal insertion of the cord is of major clinical importance because of its association with vasa praevia and fetal haemorrhage (Benkiser Syndrome). Since this condition is thought to be caused by disturbed orientation of the blastocyst at implantation it is probably related to the IVF-ET procedure.

Velamentous insertion of the umbilical cord and vasa previa

We report 31 cases with velamentous insertion of the umbilical cord of whom two had coexistent vasa previa. The prevalence of the former was 0.22% and of the latter 0.014%. Perinatal mortality was low, 3.2%, but there was a high rate of complications during pregnancy, such as threatened abortion, antepartum and intrapartum bleeding, premature delivery and fetal distress. Fifteen patients underwent caesarean section. Four of the term infants were small for gestational age. One infant had congenital malformations. The two cases with vasa previa are described in detail. We conclude that velamentous insertion of the umbilical cord should be kept in mind in the differential diagnosis of fetal distress accompanied with antepartum or intrapartum vaginal bleeding.

Vasa previa

An active obstetric service can expect to have one perinatal death each year due to vasa previa. Unfortunately, little has been done to improve the diagnosis and treatment of this condition, which presents no risk to the mother but is often fatal to the fetus. The various clinical pictures which can be associated with vasa previa are presented, along with a discussion of the techniques readily available for making the diagnosis: palpation and visualization, amnioscopy, fetal heart monitoring, and various tests for the presence of fetal hemoglobin.