Perinatal outcome of pregnancies with prenatal diagnosis of vasa previa: systematic review and meta-analysis.

OBJECTIVES: To derive accurate estimates of perinatal survival in pregnancies with and without a prenatal diagnosis of vasa previa based on a systematic review of the literature and meta-analysis. METHODS: A search of MEDLINE, EMBASE and The Cochrane Library was performed to review relevant citations reporting on the perinatal outcomes of pregnancies with vasa previa. We included prospective and retrospective cohort and population studies that provided data on pregnancies with a prenatal diagnosis of vasa previa or cases diagnosed at birth or following postnatal placental examination. Meta-analysis using a random-effects model was performed to derive weighted pooled estimates of perinatal survival (excluding stillbirths and neonatal deaths) and intact perinatal survival (additionally excluding hypoxic morbidity). Incidence rate difference (IRD) meta-analysis was used to estimate the significance of differences in pooled proportions between cases of vasa previa with and those without a prenatal diagnosis. Heterogeneity between studies was estimated using Cochran's Q and the I2 statistic. RESULTS: We included 21 studies reporting on the perinatal outcomes of 683 pregnancies with a prenatal diagnosis of vasa previa. There were three stillbirths (1.01% (95% CI, 0.40-1.87%)), five neonatal deaths (1.19% (95% CI, 0.52-2.12%)) and 675 surviving neonates, resulting in a pooled estimate for perinatal survival of 98.6% (95% CI, 97.6-99.3%). Based on seven studies that included cases of vasa previa with and without a prenatal diagnosis, the pooled perinatal survival in pregnancies without a prenatal diagnosis (61/118) was 72.1% (95% CI, 50.6-89.4%) vs 98.6% (95% CI, 96.7-99.7%) in cases with a prenatal diagnosis (224/226). Therefore, the risk of perinatal death was 25-fold higher when a diagnosis of vasa previa was not made antenatally, compared with when it was (odds ratio (OR), 25.39 (95% CI, 7.93-81.31); P < 0.0001). Similarly, the risk of hypoxic morbidity was increased 50-fold in cases with vasa previa without a prenatal diagnosis compared with those with a prenatal diagnosis (36/61 vs 5/224; OR, 50.09 (95% CI, 17.33-144.79)). The intact perinatal survival rate in cases of vasa previa without a prenatal diagnosis was significantly lower than in those with a prenatal diagnosis (28.1% (95% CI, 14.1-44.7%) vs 96.7% (95% CI, 93.6-98.8%)) (IRD, 73.4% (95% CI, 53.9-92.7%); Z = -7.4066, P < 0.001). CONCLUSIONS: Prenatal diagnosis of vasa previa is associated with a high rate of perinatal survival, whereas lack of an antenatal diagnosis significantly increases the risk of perinatal death and hypoxic morbidity. Further research should be undertaken to investigate strategies for incorporating prenatal screening for vasa previa into routine clinical practice. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Vasa Previa Diagnosis, Clinical Practice, and Outcomes in Australia.

OBJECTIVE: To estimate the incidence of women with vasa previa in Australia and to describe risk factors, timing of diagnosis, clinical practice, and perinatal outcomes. METHODS: A prospective population-based cohort study was undertaken using the Australasian Maternity Outcomes Surveillance System between May 1, 2013, and April 30, 2014, in hospitals in Australia with greater than 50 births per year. Women were included if they were diagnosed with vasa previa during pregnancy or childbirth, confirmed by clinical examination or placental pathology. The main outcome measures included stillbirth, neonatal death, cesarean delivery, and preterm birth. RESULTS: Sixty-three women had a confirmed diagnosis of vasa previa. The estimated incidence was 2.1 per 10,000 women giving birth (95% CI 1.7-2.7). Fifty-eight women were diagnosed prenatally and all had a cesarean delivery. Fifty-five (95%) of the 58 women had at least one risk factor for vasa previa with velamentous cord insertion (62%) and low-lying placenta (60%) the most prevalent. There were no perinatal deaths in women diagnosed prenatally. For the five women with vasa previa not diagnosed prenatally, there were two perinatal deaths with a case fatality rate of 40%. One woman had an antepartum stillbirth and delivered vaginally and the other four women had cesarean deliveries categorized as urgent threat to the life of a fetus with one neonatal death. The overall perinatal case fatality rate was 3.1% (95% CI 0.8-10.5). Two thirds (68%) of the 65 neonates were preterm and 29% were low birth weight. CONCLUSION: The outcomes for neonates in which vasa previa was not diagnosed prenatally were inferior with higher rates of perinatal morbidity and mortality. Our study shows a high rate of prenatal diagnosis of vasa previa in Australia and associated good outcomes.