PDF | Recopilacion y actualizacion | ResearchGate, the Una barrera placentaria completa está formada por seis capas que desde la sangre. PDF | On Aug 28, , Alexander Heazell and others published Abnormalities of the placenta. madurez placentaria (IMP), calculado dividiendo el número de membranas vásculo sinciciales alteraciones en la placenta con frecuencia se han asociado a.

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Today, the main cause of placenta accreta spectrum is uterine surgery and, myometrium, and placenta percreta where the villi invade the full. Read the latest articles of Placenta at, Elsevier's leading In Press, Accepted Manuscript, Available online 12 July ; Download PDF. Retroviruses are often expressed in the placenta. Placental expression probably evolved to facilitate retroviral transmission from mother to.

The usefulness of rotational thromboelastometry specifically in placenta accreta spectrum is uncertain but has recently been shown to reduce mortality in trauma surgery and other surgical specialties. Should uncontrolled pelvic hemorrhage ensue, a few procedural strategies are worthy of consideration. Hypogastric artery ligation may decrease blood loss, but its efficacy has not been proved and it may be ineffective because of collateral circulation.

In addition, hypogastric artery ligation can be difficult and time consuming, although it can be easily performed by experienced surgeons. The use of interventional radiology to embolize the hypogastric arteries in cases of persistent or uncontrolled hemorrhage may be useful.

Interventional radiology is especially helpful when there is no single source of bleeding that can be identified at surgery. However, it can be difficult to safely perform in unstable patients and the equipment and expertise are not available in all centers.

Other methods to address severe and intractable pelvic hemorrhage include pelvic pressure packing and aortic compression or clamping. Pelvic packing, although not standard management, can be highly effective for patient stabilization and product replacement when experiencing acute uncontrolled hemorrhage. Packing may be left in for 24 hours with an open abdomen and ventilatory support to allow for optimization of clotting and hemostasis.

Aortic clamping is likely best reserved for experienced surgical consultants or heroic measures given the potential risk of vascular-related complications from this approach. Several other factors should be considered in the setting of hemorrhage and placenta accreta spectrum. Patients should be kept warm because many clotting factors function poorly if the body temperature is less than 36oC.

Acidosis also should be avoided. If blood loss is excessive, often defined as estimated blood loss of 1, mL or greater, prophylactic antibiotics should be re-dosed Laboratory testing is critical to the management of obstetric hemorrhage. Baseline assessment at the initiation of bleeding should include platelet count, prothrombin time, partial thromboplastin time, and fibrinogen levels, which are normally elevated in pregnant women.

Rapid and accurate results can facilitate transfusion management, although the massive transfusion protocol is not based on laboratory studies. Thus, developing a protocol that allows for rapid results from a centralized laboratory or having point of care testing on the labor and delivery unit or in the general operating room is desired.

As with any case of uncontrolled hemorrhage, the following are key concepts to remember: treat the patient based on clinical presentation initially and do not wait for laboratory results, keep the patient warm, rapidly transfuse, and when transfusing in the setting of acute hemorrhage, be sure to transfuse packed red blood cells, fresh frozen plasma, and platelets in a fixed ratio.

Postoperative Considerations and Management Given the extensive surgery, placenta accreta spectrum patients require intensive hemodynamic monitoring in the early postoperative period.

This often is best provided in an intensive care unit setting to ensure hemodynamic and hemorrhagic stabilization. Close and frequent communication between the operative team and the immediate postoperative team is strongly encouraged. Postoperative placenta accreta spectrum patients are at particular risk of ongoing abdominopelvic bleeding, fluid overload from resuscitation, and other postoperative complications given the nature of the surgery, degree of blood loss, potential for multiorgan damage, and the need for supportive efforts.

Continued vigilance for ongoing bleeding is particularly important. Obstetricians and other health care providers should have a low threshold for reoperation in cases of suspected ongoing bleeding. Pelvic vessel interventional radiologic strategies may be useful, but not all cases are amenable to these less invasive approaches and their use should be considered on a case-by-case basis.

Clinical vigilance for complications such as renal failure; liver failure; infection; unrecognized ureteral, bladder, or bowel injury; pulmonary edema; and diverse intravascular coagulation is warranted. Lastly, attention to the small but real possibility of Sheehan syndrome also known as postpartum pituitary necrosis is warranted given the clinical scenario and the potential for hypoperfusion.

Lecture - Placenta Development

Despite antenatal diagnosis of placenta accreta spectrum and extensive delivery planning, it is possible that a patient may develop unexpected complications that may or may not be related to placenta accreta spectrum and that require an unscheduled delivery. It is also possible to make the diagnosis of placenta accreta spectrum after vaginal delivery.

The level and capabilities of the response will vary depending on local resources, timing, and other factors. It is important, however, that all facilities performing deliveries have considered the possibility of a case of placenta accreta spectrum and have plans in place to manage or rapidly stabilize patients in anticipation of transfer to a higher level facility per established institutional agreements 3.

With these caveats, a few general principles apply. If placenta accreta spectrum is suspected based on uterine appearance and there are no extenuating circumstances mandating immediate delivery, the case should be temporarily paused until optimal surgical expertise arrives.

In addition, the anesthesia team should be alerted and consideration given to general anesthesia, additional intravenous access should be obtained, blood products should be ordered, and critical care personnel should be alerted.

If available, cell salvage technologies should be brought into the operative suite. Patience on the part of the primary operative team is key, and they should not proceed until circumstances are optimized.

If mobilization of such a team is not possible, consideration of stabilization and transfer is appropriate, assuming maternal and fetal stability.

Many of the same principles apply when placenta accreta spectrum is inadvertently discovered with the uterus already open immediately after delivery. Once the diagnosis of placenta accreta spectrum is established and it is clear that placental removal will not occur with usual maneuvers, then rapid uterine closure and proceeding to hysterectomy as judiciously as possible should be considered.

Mobilization of appropriate resources should occur concurrently with ongoing hysterectomy in conjunction with the operating room nursing staff and anesthetic team. If the patient is stable after delivery of the fetus and the center is unable to perform the hysterectomy under optimal conditions, transfer should be considered. Temporizing maneuvers, packing the abdomen, tranexamic acid infusion, and transfusion with locally available products should be considered.

Comparative aspects of trophoblast development and placentation

Uterine Preservation and Expectant Management Uterine preservation, referred to here as conservative management, is usually defined as removal of placenta or uteroplacental tissue without removal of the uterus. Expectant management is defined as leaving the placenta either partially or totally in situ. Because placenta accreta spectrum is potentially life threatening, hysterectomy is the typical treatment. Consideration of conservative or expectant approaches should be rare and considered individually.

Major complications of treatment of placenta accreta spectrum are loss of future fertility, hemorrhage, and injury to other pelvic organs.

To reduce these complications, some have advocated conservative or expectant management in patients with placenta accreta spectrum 83 , As defined previously, conservative management is removal of the placenta or uteroplacental tissue without removing the uterus.

For patients with focal placental adherence, removal of the placenta by either manual extraction or surgical excision followed by repair of the resulting defect has been associated with uterine preservation in some cases Although randomized trials that compared hysterectomy to this approach are not available, it is apparent that blood loss is significantly less in a patient with a small defect using this approach.

In patients with too large a defect to subsequently repair, there are data that suggest that en bloc removal of the entire uteroplacental defect followed by uterine closure results in reduced blood loss and maintains potential fertility It is noteworthy that these conservative approaches have been reported only in small numbers of cases and it is unclear that all the patients included actually had placenta accreta spectrum.

Accordingly, efficacy remains uncertain. In patients with more extensive placenta accreta spectrum, expectant management is considered an investigational approach.

With expectant management, the cord is ligated near the placenta and the entire placenta is left in situ, or only the placenta that spontaneously separates is removed before uterine closure. Data are limited to case series when evaluating expectant management.

In the larger series, those with successful expectant management had a median time to placental involution of Of the 36 patients who required hysterectomy, 18 were primary failures, occurring within 24 hours of primary cesarean, and 18 were delayed failures, occurring more than 24 hours after delivery All early failures and the majority of secondary failures were secondary to increased bleeding. The degree of success with expectant management, defined as leaving the placenta in situ, of placenta accreta spectrum appears to correlate with the degree of placental attachment abnormality.

Although these outcomes with expectant management are promising, it is unclear that these women truly had placenta accreta spectrum because successful cases had no histologic confirmation; in general, case series of expectant management included far fewer women with traditional risk factors such as previa and prior cesarean deliveries than cases reported using planned cesarean hysterectomy Thus, the chance of favorable outcomes may be overestimated.

Taking these limited published data together, and the accepted approach of hysterectomy to treat placenta accreta spectrum, conservative management or expectant management should be considered only for carefully selected cases of placenta accreta spectrum after detailed counseling about the risks, uncertain benefits, and efficacy and should be considered investigational.

Adjuncts to Conservative and Expectant Management In addition to leaving the placenta in situ, investigators have used adjunctive measures to diminish blood loss, hasten placental reabsorption, or both. Techniques have included uterine devascularization with uterine artery balloon placement, embolization or ligation, and postdelivery methotrexate administration 87— Methotrexate use in expectant management of placenta accreta spectrum is advocated by some authors who contend that it will hasten placental involution and resorption The biologic plausibility of this premise may be questioned because methotrexate targets rapidly dividing cells and division of third trimester placental cells is limited.

Further, methotrexate has the potential for maternal hematologic and nephrologic toxicities and is contraindicated in breastfeeding because of neonatal morbidity 83, In a large case series of expectant management of placenta accreta spectrum, there was one maternal death, which was ascribed to severe methotrexate toxicity and subsequent septic shock Given the unproven benefit and possible harm, methotrexate to hasten placental resorption is not recommended For expectantly managed patients with persistent placental tissue with or without substantial bleeding, hysteroscopic resection of the placental remnants has been proposed as an adjunctive treatment.

In the largest series in which specific outcomes were delineated, 12 women with persistent placental tissue underwent hysteroscopic resection with only one requiring a subsequent hysterectomy One half of the women required more than one procedure and one third required more than two procedures.

Of the 11 successful cases, nine women resumed normal menstruation. High-intensity focused ultrasonography has also been used in conjunction with hysteroscopic resection. The procedure was deemed a success in all 25 patients, but 9 required more than one hysteroscopic resection Two patients had uterine perforations at the time of resection, which was attributed to the thinning of the uterine wall by the high-intensity focused ultrasonography; one had hemorrhagic shock and required emergent uterine repair.

Given these limited data, the frequency of adverse events, and the proportion of patients who needed a repeat procedure, routine hysteroscopic resection with or without antecedent high-intensity focused ultrasonography is not recommended. Delayed Interval Hysterectomy Delayed interval hysterectomy is a derivative of an expectant approach to placenta accreta spectrum, except that future fertility is not a consideration, and minimizing blood loss and tissue damage are the primary goals.

Patients with placenta percreta are optimal candidates for this procedure because they have an increased risk of blood loss and tissue damage if hysterectomy is performed at the time of cesarean delivery In the largest series to date, 13 women with suspected placenta percreta underwent delayed hysterectomy at a median of 41 days after elective cesarean delivery Total blood loss for the primary cesarean delivery was mL and mL for the delayed hysterectomy, which is lower than the median 3, mL blood loss reported for primary removal in the largest review With regard to organ damage, incidental cystotomy was reported in two patients and ureteral injury in one.

No patient required bladder resection. Although these preliminary data are encouraging, use of this method warrants caution. The reported cases are small in number and were performed at one academic medical center. Accordingly, counseling should acknowledge significant uncertainty regarding efficacy and significant potential risks, and this approach should be considered investigational without additional data.

Future Fertility Expectant management of placenta accreta spectrum appears to have minimal effect on subsequent fertility but does carry a high recurrence risk of placenta accreta spectrum.

Three women had been attempting pregnancy for approximately 1 year, and 24 women had 34 pregnancies. Of the 32 continuing pregnancies, 10 were miscarriages, 1 was an ectopic pregnancy, and 21 gave birth after 34 weeks of gestation. Of the third trimester deliveries, 6 out of 21 women Other series reported similar rates of pregnancy success and also described increased placenta accreta spectrum recurrence rates ranging from Summary Placenta accreta spectrum is becoming increasingly common and is associated with significant morbidity and mortality.

Knowledge of risk factors and antenatal imaging expertise can help guide the diagnosis. Preparation for delivery and postpartum care should involve a multidisciplinary team and early antepartum consultations guided by the levels of maternal care 3.

Cesarean hysterectomy can be challenging and should be performed by the most experienced surgeons. Because of intrapartum and postpartum bleeding risk for women with placenta accreta spectrum, centers caring for these patients should have the ability to rapidly mobilize blood products for transfusion. When placenta accreta spectrum is encountered at the time of delivery without a prior suspicion or diagnosis and there are no extenuating circumstances mandating immediate delivery, anesthesia staff should be alerted, and the case should be temporarily paused until optimal surgical expertise can be garnered.

If the delivering center lacks the expertise to perform a hysterectomy and the patient is stable after delivery of the fetus, the patient should be transferred to a facility that can perform the necessary level of care.

For More Information The American College of Obstetricians and Gynecologists has identified additional resources on topics related to this document that may be helpful for ob-gyns, other health care providers, and patients. You may view these resources at www. These resources are for information only and are not meant to be comprehensive. The resources may change without notice. Placenta previa-accreta: risk factors and complications.

Am J Obstet Gynecol ;—9. The frequency and complication rates of hysterectomy accompanying cesarean delivery. Obstet Gynecol ;—9. Levels of maternal care. Obstetric Care Consensus No. American College of Obstetricians and Gynecologists.

Obstet Gynecol ;— Abnormal placentation: twenty-year analysis. Am J Obstet Gynecol ;— Placenta accreta: changing clinical aspects and outcome. Obstet Gynecol ;—4. Clinical risk factors for placenta previa-placenta accreta. Am J Obstet Gynecol ;—4.

Recent trends in placenta accreta in the United States and its impact on maternal-fetal morbidity and healthcare-associated costs, J Matern Fetal Neonatal Med ;— Placenta accreta: risk factors, perinatal outcomes, and consequences for subsequent births.

Am J Obstet Gynecol ; Risk factors for placenta accreta: a large prospective cohort. Am J Perinatol ;— Impact of multiple cesarean deliveries on maternal morbidity: a systematic review. Garmi G, Salim R. Epidemiology, etiology, diagnosis, and management of placenta accreta. Obstet Gynecol Int ; Antecedents of abnormally invasive placenta in primiparous women: risk associated with gynecologic procedures.

Maternal morbidity associated with multiple repeat cesarean deliveries. Placenta accreta is associated with elevated maternal serum alpha-fetoprotein. Maternal serum markers, characteristics and morbidly adherent placenta in women with previa. J Perinatol ;—4. Elevated first trimester PAPP--a is associated with increased risk of placenta accreta. Prenat Diagn ;— Can venous ProBNP levels predict placenta accreta?

J Matern Fetal Neonatal Med ;—4. Placenta ;—5. Effects of maternal smoking on the placental expression of genes related to angiogenesis and apoptosis during the first trimester.

PLoS One ;9:e Cell-free placental mRNA in maternal plasma to predict placental invasion in patients with placenta accreta. Int J Gynaecol Obstet ;—3. Placenta accreta spectrum: pathophysiology and evidence-based anatomy for prenatal ultrasound imaging. Pathophysiology of placenta creta: the role of decidua and extravillous trophoblast. Placenta ;— Optimal management strategies for placenta accreta. BJOG ;— Maternal morbidity in cases of placenta accreta managed by a multidisciplinary care team compared with standard obstetric care.

Obstet Gynecol ;—7. Effect of predelivery diagnosis in 99 consecutive cases of placenta accreta. Maternal morbidity in patients with morbidly adherent placenta treated with and without a standardized multidisciplinary approach. Prenatal diagnosis of placenta accreta: is sonography all we need?

J Ultrasound Med ;— The antenatal diagnosis of placenta accreta. BJOG ; Prenatal identification of invasive placentation using ultrasound: systematic review and meta-analysis. Ultrasound Obstet Gynecol ;— Interobserver variability of sonography for prediction of placenta accreta. J Ultrasound Med ;—8. Proposal for standardized ultrasound descriptors of abnormally invasive placenta AIP. Ultrasound Obstet Gynecol ;—5. Methods to induce labour: a systematic review, network meta-analysis and cost-effectiveness analysis.

Abnormally invasive placenta-prevalence, risk factors and antenatal suspicion: results from a large population-based pregnancy cohort study in the Nordic countries.

Cesarean scar pregnancy is a precursor of morbidly adherent placenta. Natural history of early first-trimester pregnancies implanted in Cesarean scars. Perinatal outcome of pregnancies complicated by placenta accreta. Diagnosis and morbidity of placenta accreta. Ultrasound Obstet Gynecol F1;—7.

Magnetic resonance imaging is often misleading when used as an adjunct to ultrasound in the management of placenta accreta spectrum disorders. Lead and trace element levels in placenta, maternal and cord blood: a cross-sectional pilot study. J Obstet Gynaecol Res ;— Serial change in cervical length for the prediction of emergency cesarean section in placenta previa. PLoS One ;e Cervical length and risk of antepartum bleeding in women with complete placenta previa. Ultrasonographic cervical length and risk of hemorrhage in pregnancies with placenta previa.

Cervical length in patients at risk for placenta accreta. J Ultrasound Med ;—6. Center of excellence for placenta accreta. Am J Obstet Gynecol ;—8. Placenta accreta spectrum: accreta, increta, and percreta. Obstet Gynecol Clin North Am ;— Regionalization of care for obstetric hemorrhage and its effect on maternal mortality. Second-trimester abortion. Practice Bulletin No. Effectiveness of timing strategies for delivery of individuals with placenta previa and accreta.

Placenta accreta. Surgical management of placenta accreta: a cohort series and suggested approach.

Gyamfi-Bannerman C. Am J Obstet Gynecol ;B2—8.

Antenatal corticosteroid therapy for fetal maturation. Committee Opinion No. Obstet Gynecol ;e—9. Multidisciplinary team learning in the management of the morbidly adherent placenta: outcome improvements over time.

Hypogastric artery ligation for obstetric hemorrhage. Obstet Gynecol ;—6. Practice guidelines for obstetric anesthesia: an updated report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia and the Society for Obstetric Anesthesia and Perinatology. Anesthesiology ;— Outcomes of planned compared with urgent deliveries using a multidisciplinary team approach for morbidly adherent placenta.

Predictors for emergency cesarean delivery in women with placenta previa. A score to predict the risk of emergency caesarean delivery in women with antepartum bleeding and placenta praevia. Cardiovasc Intervent Radiol ;— Temporary balloon occlusion of the common iliac artery: new approach to bleeding control during cesarean hysterectomy for placenta percreta.

Prophylactic balloon occlusion of the internal iliac arteries to treat abnormal placentation: a cautionary case. Preoperative intravascular balloon catheters and surgical outcomes in pregnancies complicated by placenta accreta: a management paradox. Prophylactic use of intravascular balloon catheters in women with placenta accreta, increta and percreta. Case-control comparison of cesarean hysterectomy with and without prophylactic placement of intravascular balloon catheters for placenta accreta.

Precesarean prophylactic balloon catheters for suspected placenta accreta: a randomized controlled trial. Obstet Gynecol ;—8. Multiple complications following the use of prophylactic internal iliac artery balloon catheterisation in a patient with placenta percreta. Int J Obstet Anesth ;—3. Use of prophylactic antibiotics in labor and delivery. A standardized approach for transfusion medicine support in patients with morbidly adherent placenta.

Anesth Analg ;—8. Postpartum hemorrhage. Obstet Gynecol ;e— In the present scope authors reported new findings in the field of placental angiogenesis, discussed the advancements made in the diagnosis of pathologies reported to be associated with placental angiogenesis, and brought new insights into the processes of vasculogenesis and angiogenesis occurring throughout pregnancy in the placenta.

More importantly, regulators of the key protagonists of vascular and angiogenic processes have been reported and their roles discussed.

The reviews by M. Dakouane-Giudicelli et al. Pavlov et al. Alfaidy et al. Netrin-1 and netrin-4 have been found to be either proangiogenic or antiangiogenic factors in the human placenta. These opposite effects appear to be related to the endothelial cell phenotype studied and seem also to depend on the type of receptor to which each netrin binds. The review by N. More importantly, this article argues for EG-VEGF clinical relevance as a potential biomarker of the onset of pregnancy pathologies and discusses its potential usefulness for future therapeutic directions.

In a second set of reviews of the scope Dr. Pereira et al. In the same context, S. Cvitic et al.

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In relation to immune placental pathologies that affect placental vascularization and angiogenesis, J. Haumonte et al.Abnormal placentation: twenty-year analysis. Examination of these tissues in egg-laying and other independently evolved live bearing vertebrates has shown us that many of these signalling molecules are expressed widely in vertebrate species and were probably expressed in the ancestral amniote vertebrate.

Methotrexate use in expectant management of placenta accreta spectrum is advocated by some authors who contend that it will hasten placental involution and resorption Abruptio Placenta - a retroplacental blood clot formation, abnormal hemorrhage prior to delivery. In lizards and snakes[ edit ] As placentation often results during the evolution of live birth, the more than origins of live birth in lizards and snakes Squamata have seen close to an equal number of independent origins of placentation.

Proposal for standardized ultrasound descriptors of abnormally invasive placenta AIP.