Prenatal diagnosis and postnatal outcome of Type-III vasa previa: systematic review of literature.

OBJECTIVE: Type-III vasa previa (VP) is a rare form of VP, not necessarily associated with other placental or vascular anomalies, in which aberrant vessels run from the placenta to the amniotic membranes, near the internal cervical os, before returning to the placenta. Early diagnosis of Type-III VP is important but technically challenging. The objective of this study was to gather the current available evidence on the perinatal diagnosis and outcome of Type-III VP. METHODS: A systematic review of the literature on the perinatal diagnosis of atypical Type-III VP was carried out in PubMed, MEDLINE and EMBASE accordingto PRISMA guidelines from inception to March 2023. Data extraction and tabulation were performed by two operators and checked by a third senior author. The quality of the included studies was evaluated using the National Institutes of Health tool for the quality assessment of case-series studies. Our local ultrasound database was searched for previously unreported recent cases. Characteristics of prenatally and postnatally diagnosed Type-III VP, including clinical features and perinatal outcomes, were summarized using descriptive statistics. RESULTS: Eighteen cases of Type-III VP were included, of which 16 were diagnosed prenatally (14 cases were retrieved from 10 publications and two were unpublished cases from our center) and two were diagnosed postnatally (retrieved from two publications). All prenatal cases were diagnosed on transvaginal ultrasound at a mean gestational age of 29 weeks (median, 31 weeks; range, 19-38 weeks). Conception was achieved with in-vitro fertilization in 4/16 (25.0%) cases. There were no prenatal symptoms in 15/18 (83.3%) cases, while in two (11.1%) cases there was vaginal bleeding and in one (5.6%) preterm labor occurred. In 15/18 (83.3%) cases, at least one placental abnormality was observed, including low-lying insertion (9/17), succenturiate or accessory lobe (1/17), velamentous cord insertion (3/18) and marginal insertion (9/18). All prenatally diagnosed cases were liveborn and were delivered by Cesarean section before rupture of membranes at a median gestational age of 35 weeks (range, 32-38 weeks) without neonatal complications. Emergency Cesarean section was performed in 2/16 (12.5%) cases with a prenatal diagnosis and 1/2 (50.0%) cases with a postnatal diagnosis (P = 0.179). Among those with data available, an Apgar score of ≤ 7 was observed in the prenatally vs postnatally diagnosed group in 5/13 vs 1/1 cases, respectively, at the 1-min evaluation and 3/13 vs 1/1 cases, respectively, at the 5-min evaluation. CONCLUSIONS: The prenatal diagnosis of Type-III VP is challenging, with few cases reported in the literature; however, it is crucial for minimizing the risk of adverse outcome by enabling early-term elective Cesarean delivery prior to rupture of membranes. Given that clinical manifestations and risk factors are non-specific, and that Type-III VP cannot be excluded when there is a normal cord insertion or a singular placental mass, systematic screening by transvaginal ultrasound in the general pregnant population is recommended, particularly in those with a low-lying or morphologically abnormal placenta and those who conceived using assisted reproductive technology. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Emergencies associated with pregnancy and delivery: peripartum hemorrhage.

INTRODUCTION: Peripartum hemorrhage is one of the leading causes of maternal death worldwide (25%). METHODS: Selective literature review, including international guidelines, for assessment of the causes and optimal management of this condition. RESULTS: The major causes of hemorrhage are uterine atony, placenta previa, and abruptio placentae. The diagnosis of hemorrhage is suspected from its clinical manifestations and confirmed by ultrasonography. In placenta previa, the placenta is implanted in the lower uterine segment and may cover the internal cervical os. Placenta previa is more common in older and multiparous mothers, as well as in mothers who have previously undergone a cesarean section. Placental abruption is defined as separation of the placenta from the uterine wall before delivery of the infant. The risk factors for this condition include preeclampsia, advanced maternal age, and trauma. When it presents with manifestations of acute blood loss, premature abruption placentae must be diagnosed rapidly and treated without delay to save the life of the mother and child. A rare, but highly lethal, cause of bleeding is amniotic fluid embolism, which manifests itself with sudden and unexplained peripartum respiratory distress and cardiovascular collapse. Amniotic fluid embolism is associated with high fetal and maternal mortality (20% and 60% to 80%, respectively) even when it is optimally treated. DISCUSSION: Peripartum hemorrhage is an important source of maternal and fetal morbidity and mortality. The prognosis for both mother and child can be markedly improved if the risk factors for hemorrhage are recognized and the problem is treated rapidly and appropriately when it arises.