Vasa praevia: Should we routinely screen high-risk women for this rare but serious condition?

Vasa praevia is described as the unprotected fetal vessels traversing through the placental membranes over the cervical os, below the fetal presenting part and unprotected by placental tissue or the umbilical cord. It is often not detected antenatally and presents with painless bleeding and rapid fetal compromise after spontaneous or artificial rupture of the membranes, which causes trauma to these vessels. It is a rare condition affecting one in 2500 pregnancies and has a reported perinatal mortality rate of up to 60%. More than 80% of cases of vasa praevia have at least one risk factor for the condition and it has been shown that identification of vasa praevia antenatally results in fetal survival rates of up to 97%. Risk factors include placenta praevia, velamentous cord insertion, bi-lobed placenta, succenturiate lobe, assisted reproduction and multiple pregnancy. Screening for vasa praevia with transvaginal ultrasound has been shown to be sensitive and cost effective when used in a targeted population where risk factors are present. Here, we present the antenatal assessment and management of a case of vasa praevia detected during the routine 20-week anatomy scan of a healthy primigravida, which resulted in elective caesarean section delivery of a healthy baby at 36 weeks' gestation. The pathophysiology of vasa praevia is discussed and the methods and role of screening for this rare but serious condition are appraised.

Bilateral absence of adrenal glands: a case series that expands the spectrum of associations and highlights the difficulties in prenatal diagnosis.

Adrenal agenesis (AA) defined by the complete absence of development of adrenals is a rare anomaly, which is documented mainly in experimental animals and less frequently in human subjects in the literature. This study was aimed at describing the varied phenotype of this condition in two stillborn and one termination of pregnancy fetuses and two neonates, the associated abnormalities and the difficulties encountered to achieve the prenatal diagnosis. Five cases with AA diagnosed at post-mortem examination were selected and their characteristics were analyzed. The detection of this unusual condition has usually been made as an incidental discovery at post-mortem examination. None of the cases described in this series had been diagnosed at prenatal ultrasonography. Respiratory distress was the commonest clinical presentation in the liveborn. Maternal diabetes was associated with one case. Anomalies of kidneys, lungs, spleen, and blood vessels were associated with two of the cases. No gonadal abnormalities were detected in any of the cases. These cases illustrate the varied clinical presentation of this rare condition and confirm the difficulty in achieving a prenatal diagnosis.

Cranial vault defects: the description of three cases that illustrate a spectrum of anomalies.

Three cases of cranial vault defects in fetuses are described. All 3 cases underwent postmortem examination, and in 2 of them postmortem magnetic resonance imaging was also performed. The phenotypical differences between the cases illustrate a spectrum of cranial vault defects, associated anomalies, and pathogenic mechanisms involved in the etiology of this rare malformation. All 3 cases were male, and the cranial vault defects corresponded to exencephaly with acrania/acalvaria caused by amniotic band syndrome, acalvaria, and acrania presenting in a chorangiopagus parasiticus twin.