Placenta previa research pdf

Objectives: Describe the risk factors for placenta previa. Describe the pathophysiology of placenta previa. Describe the management of patients with placenta previa and how this varies with gestational age, presentation, and stability of the patient. Explain the importance of improving care coordination, collaboration, and communication amongst an interprofessional team to enhance the delivery of care and improve outcomes for patients with placenta previa.

Access free multiple choice questions on this topic. Uncontrolled postpartum hemorrhage from placenta previa or PAS may necessitate a blood transfusion, hysterectomy thus leaving the patient infertile, admission to the ICU, or even death. The underlying cause of placenta previa is unknown. There is, however, an association between endometrial damage and uterine scarring.

The outer layer of the dividing zygote, blastocyst, is made up of trophoblast cells which develops into the placenta and fetal membranes. The trophoblast adheres to the decidua basalis of the endometrium, forming a normal pregnancy. Prior uterine scars provide an environment that is rich in oxygen and collagen.

The trophoblast can adhere to the uterine scar leading to the placenta covering the cervical os or the placenta invading the walls of the myometrium.

Placenta previa affects 0. Placenta previa is the complete or partial covering of the cervix. A low-lying placenta is where the edge is within 2 to 3. The risks factors for placenta previa include a history of advanced maternal age age greater than 35 years old , multiparity, smoking, history of curettage, use of cocaine, and history of cesarean section s. However, it may also represent an altered hormonal or implantation environment. Painless vaginal bleeding during the second or third trimester of pregnancy is the usual presentation.

The bleeding may be provoked from intercourse, vaginal examinations, labor, and at times there may be no identifiable cause. Sometimes the placenta can be visualized on speculum examination if the cervix is dilated. A digital examination should be avoided to prevent massive hemorrhage. Routine sonography in the first and second trimester of pregnancy provides early identification of placenta previa.

It is important to realize that the earlier the diagnosis of placenta previa is, the more likely it is to resolve at delivery secondary to placental migration. A patient presenting with vaginal bleeding in the second or third trimester should receive a transabdominal sonogram before a digital examination.

If there is a concern for placenta previa, then a transvaginal sonogram should be performed to confirm the location of the placenta. Transvaginal sonogram has been shown to be superior to a transabdominal sonogram and is safe.

At the time of sonography, evaluation for PAS is also necessary. High suspicion for placenta accreta should be a consideration early on in diagnosis. Placenta accreta is the attachment of the placenta beyond the normal boundary of the myometrium that is established by the Nitabuch fibrinoid layer. Placenta accreta spectrum diagnosis is via ultrasonography with very high sensitivities and specificities. However, they are costly and have not been shown to improve diagnosis or outcomes compared to ultrasonography alone.

The plan should be to leave the placenta in situ to avoid massive hemorrhage. With the diagnosis of placenta previa, the patient is scheduled for elective delivery at 36 to 37 weeks via cesarean section. Patients who present with a known history of placenta previa and vaginal bleeding should have vitals performed, and should have electronic fetal monitoring initiated.

The patient should receive two large-bore intravenous lines with a complete blood count, type and screen, and have coags drawn. If she presents with substantial bleeding, then units of blood should be crossed and matched. Patients with excessive or continuous vaginal bleeding should be delivered via cesarean section regardless of gestational age.

If bleeding subsides then expectant management is permissible if the gestational age is less than 36 weeks. If at or greater than 36 weeks of gestation then cesarean delivery is recommended. Bedrest, reduced activity, and avoidance of intercourse are commonly mandated, though there is no clear benefit.

Inpatient vs. A cesarean section should optimally occur under controlled conditions. A discussion with the patient should take place during prenatal care of the diagnosis, possible complications, and the plan for cesarean section and possible hysterectomy if there is uncontrolled postpartum hemorrhage or PAS.

Management and maternal outcome In the management of our cases Fetal outcome There were boys Table 3 Factors associated with severe maternal morbidity as defined with admission to ICU 26 patients out of Footnotes Disclosure. References 1. Massive or recurrent antepartum haemorrhage. Current Obstet Gynaecol. Impact of multiple cesarean deliveries on maternal morbidity: a systematic review. Am J Obstet Gynecol. Etiology and risk factors for placenta previa: an overview and meta-analysis of observational studies.

J Matern Fetal Neonatal Med. Rates of caesarean section: analysis of global, regional and national estimates. Paediatr Perinat Epidemiol.

Epidemiology and trends for Caesarean section births in New South Wales, Australia: a population-based study. BMC Pregnancy Childbirth. Blackwell SC. Timing of delivery for women with stable placenta previa. Semin Perinatol. Placenta previa and the risk of delivering a small-for-gestational-age newborn. Obstet Gynecol. Oyelese Y, Smulian JC. Placenta previa, placenta accreta, and vasa previa. Conservative management of placenta previa-accreta by prophylactic uterine arteries ligation and uterine tamponade.

Fetal Diagn Ther. Maternal and neonatal outcomes of placenta previa and placenta accreta: three years of experience with a two-consultant approach. Int J Womens Health. Risk factors and pregnancy outcome in different types of placenta previa. J Obstet Gynaecol Can. This is clearly demonstrated in elective caesarean section when this distance is 1 cm or less.

Table 3 and is illustrated in Fig. Knowledge of the placental significant postpartum haemorrhage remains high. Cases location, which was available to the clinicians managing where the placenta is more than 2 cm from the internal os the case, would probably have played an important part in have a high chance of vaginal delivery and should be defined the decision to perform an operative delivery.

Clinicians may have been happier to conduct a trial of labour if they had sufficient scientific evidence to support an expectant management strategy. Acknowledgements When evaluating the likelihood of vaginal delivery, it is clear from the data that placenta praevia reaching or over- Dr Prefumo was supported by a Marie Curie Fellowship lapping the internal cervical os requires elective caesarean of the European Community programme Quality of Life delivery.

In Group 2, where the placental edge to internal os distance was 0. References However, all women with a placental edge to internal os distance of 1 cm or less required a caesarean delivery. Figure 1. Bleeding in late pregnancy. High Risk Pregnancy: Man- 1 also demonstrates a trend for decreasing caesarean section agement Options, 2nd edition. Philadelphia: Saunders, Oyelese Y. Placenta praevia and vasa praevia: time to leave the dark Given the retrospective nature of the study and the likely ages.

Ultrasound Obstet Gynecol ; — A prospective ford J, Fairbanks LA. What is a low-lying placenta? Am J Obstet Gynecol ; — It may be Translabial ultrasonography and placenta previa: does measurement appropriate to allow these women a trial of labour with of the os — placenta distance predict outcome?

J Ultrasound Med ; suitable precautions to manage emergency operative deliv- — Obstetric hemorrhage. Gant NF, et al. Williams Obstetrics, 20th edition. Stamford, The data of this study demonstrate that the likelihood for Connecticut: Appleton and Lange, — It is important to note that a assessment, progress and outcome. These data are supported ment. Radiology ; — Transvaginal ultrasonography in predicting placenta previa praevia was made on clinical grounds Ultrasound Obstet Gynecol ; All the cases of postpartum haemorrhage in the present — The use of second- series occurred in women who had undergone a caesarean trimester transvaginal sonography to predict placenta previa.

Pietro Beretta. Ilaria Follesa. A short summary of this paper. Placenta previa: distance to internal os and mode of delivery. Research www. Am J Obstet Gynecol ; During the third trimester, mea- proximity of the internal os. There is However, the optimal mode of delivery previa distance between 1 and 20 mm consensus that a placenta previa that to- for cases with a distance from placental from the cervical os and to examine the tally or partially overlies the internal os edge to internal os between 1 and 20 mm rates of cesarean section delivery at dif- requires delivery by cesarean section.

More controversial is the optimal mode city of data. All women who were regis- ; accepted June 1, Gerardo, Via Solferino, 16, Monza, Italy. There was ing on clinical circumstances. All rights reserved.

Clinical Expert Series report concluded all women with antepartum hemorrhage doi: All cases that were followed be- cesarean. The diagnosis of delivery among cases with a distance be- placenta previa was made when the Postpartum nancies, 3 viable offspring with a examination.

The not migrate at follow-up scans. She never the center of the internal cervical os and study was approved on April 13, experienced bleeding episodes during the leading edge of the placenta was mea- protocol no.