Placenta Previa, Placenta Accreta, and Vasa Previa

Abstract

Placenta previa, placenta accreta, and vasa previa are important causes of bleeding in the second half of pregnancy and in labor. Risk factors for placenta previa include prior cesarean delivery, pregnancy termination, intrauterine surgery, smoking, multifetal gestation, increasing parity, and maternal age. The diagnostic modality of choice for placenta previa is transvaginal ultrasonography, and women with a complete placenta previa should be delivered by cesarean. Small studies suggest that, when the placenta to cervical os distance is greater than 2 cm, women may safely have a vaginal delivery. Regional anesthesia for cesarean delivery in women with placenta previa is safe. Delivery should take place at an institution with adequate blood banking facilities. The incidence of placenta accreta is rising, primarily because of the rise in cesarean delivery rates. This condition can be associated with massive blood loss at delivery. Prenatal diagnosis by imaging, followed by planning of peripartum management by a multidisciplinary team, may help reduce morbidity and mortality. Women known to have placenta accreta should be delivered by cesarean, and no attempt should be made to separate the placenta at the time of delivery. The majority of women with significant degrees of placenta accreta will require a hysterectomy. Although successful conservative management has been described, there are currently insufficient data to recommend this approach to management routinely. Vasa previa carries a risk of fetal exsanguination and death when the membranes rupture. The condition can be diagnosed prenatally by ultrasound examination. Good outcomes depend on prenatal diagnosis and cesarean delivery before the membranes rupture.

Beyond maternal death: improving the quality of maternal care through national studies of ‘near-miss’ maternal morbidity

“…Placenta accreta, increta or percreta are associated with major pregnancy complications 58 and are thought to be becoming more common 59 owing to a number of factors including rising maternal age at delivery and an increasing proportion of deliveries by caesarean. 60,61 This finding is of particular concern in the context of increasing rates of caesarean delivery and older maternal age at childbirth.…”

A rare case report of hysterotomy for retained placenta accreta in bicornuate uterus

“…1 It is caused by defective decidua basalis resulting in abnormal invasive placental implantation, associated with significant maternal mortality and morbidity. 2 The invasion of superficial myometrium is placenta accreta, invasion into deeper myometrial layer is placenta increta, and invasion through the serosa and/ or adjacent pelvic organs is placenta percreta. 3 Most of the cases are diagnosed at the time of delivery when failed attempts during manual removal of placenta.…”

“…4 It may result in massive obstetric haemorrhage, leading to disseminated intravascular coagulopathy, may need hysterectomy, surgical injury to ureter, bladder, bowel or neurovascular structures, adult respiratory distress syndrome, acute transfusion reaction, electrolyte imbalance, renal failure, infectious morbidities and loss of fertility. 2,5 Maternal mortality is high up to 9%. 6 Ultrasonography is sufficient to diagnose placenta accreta with a sensitivity of 77-87% and 96-98% specificity.…”

Morbidly Adherent Placenta in Mid Trimester Abortion - A Case Report

“…The most influential variable on maternal outcome is not attempting to remove the placenta. A recent review also advised against attempts at placental removal before hysterectomy 15 . Hysterectomy has traditionally been advised in the management of placenta accrete but there has been a recent movement towards conservative management and preservation of fertility.…”