Placenta Previa

DRG Category: 786

Mean LOS: 6.3 days

Description: Surgical: Cesarean Section Without Sterilization With Major Complication or Comorbidity

DRG Category: 787

Mean LOS: 4.0 days

Description: Surgical: Cesarean Section Without Sterilization With Complication or Comorbidity

DRG Category: 805

Mean LOS: 4.0 days

Description: Medical: Vaginal Delivery Without Sterilization or Dilation & Curettage With Major Complication or Comorbidity

DRG Category: 806

Mean LOS: 2.7 days

Description: Medical: Vaginal Delivery Without Sterilization or Dilation & Curettage With Complication or Comorbidity

Introduction ⬆ ⬇

Placenta previa occurs in 1.9 per 1,000 primiparous singleton pregnancies and 3.9 per 1,000 multiparous singleton pregnancies. Normally, the placenta implants in the body (upper portion) of the uterus. Implantation allows for delivery of the infant before the delivery of the placenta. With placenta previa, the placenta is implanted in the lower uterine segment over or near the internal os of the cervix. As the uterus contracts and the cervix begins to efface and dilate, the villi of the placenta begin to tear away from the uterine wall, and bright red, painless, vaginal bleeding occurs. The bleeding is facilitated by the poor ability of the myometrial fibers of the lower uterine segment to contract and constrict the torn vessels. Bleeding can occur antepartum or during labor and delivery. Hemorrhage from the placental site may continue into the postpartum period because the lower uterine segment contracts poorly, contrasted with the fundus and body of the uterus. Placenta previa is classified in four ways depending on the degree of placental encroachment on the cervical os (Box 1).

The degree of the previa depends largely on the cervical dilation. For example, a marginal previa at 2 cm may become a partial previa at 8 cm because the dilating cervix uncovers the placenta. Sometimes, a placenta may correct itself, especially if it is low lying; as the uterus enlarges, the placenta moves cephalad. Depending on the amount of blood loss and gestational age of the fetus, placenta previa may be life-threatening to both the birthing parent and the fetus. Complications for the birthing parent include infection, thromboembolic phenomenon, shock, and death. Complications for the fetus include slow fetal growth due to insufficient blood supply, anemia, and fetal distress due to hypoxemia.

Box 1 Classification of Placenta Previa

Low Lying

The placenta implants in the lower uterine segment but does not reach the cervical os; often this type of placenta previa moves upward as the pregnancy progresses, eliminating bleeding complications later.

Marginal

The edge of the placenta is at the edge of the internal os; the birthing parent may be able to deliver vaginally.

Partial

The placenta partially covers the cervical os; as the pregnancy progresses and the cervix begins to efface and dilate, bleeding occurs.

Total

The placenta covers the entire cervical os; this usually requires an emergency cesarean section.

Causes ⬆ ⬇

The cause of placenta previa is unknown. Risks include birthing parents of advanced age (over age 35 years); those who have a history of uterine surgeries (cesarean sections, dilation and curettage, abortions) and infections with endometritis, and those who have had a previous placenta previa. It is also more common in birthing parents with previous pregnancies and those who currently have a multiple gestation with a large placenta. Smoking and cocaine use are also contributing factors.

Genetic Considerations ⬆ ⬇

No clear genetic contributions to susceptibility have been defined.

Sex and Life Span Considerations ⬆ ⬇

Placenta previa is more common in birthing parents of advanced age and in patients with multiparity. It is more strongly associated with advanced age of birthing parent than placental abruption and occurs in approximately 1 of 1,500 deliveries of patients who are age 19 years and 1 in 100 deliveries of those over age 35 years. The incidence of placenta previa has increased over the past 30 years; this increase is attributed to the shift in older birthing parents having infants. Overall incidence is 1 in 200 deliveries; risk for recurrence may be as high as 10% to 15%. The birthing parent mortality rate from previas is 0.3%.

Health Disparities and Sexual/Gender Minority Health ⬆ ⬇

Nurses have a significantly higher risk of anemia, placenta previa, and pregnancy-associated hypertensive diseases and preeclampsia during the antenatal period than nonmedical working birthing parents. Ethnicity, race, and sexual/gender minority status have no known effect on the risk for placenta previa.

Global Health Considerations ⬆ ⬇

While no global data are available, placenta previa occurs around the world.

Assessment ⬆ ⬇

ASSESSMENT

History

Although many patients who develop placenta previa have an unremarkable obstetric or gynecologic history, some have had previous uterine surgeries or infections. The prenatal course of the current pregnancy is often uneventful until the patient experiences a bout of bright red, painless bleeding. Question the patient as to the onset and amount of bleeding first noticed. The initial bleeding in placenta previa is often scant because few uterine sinuses are exposed.

Physical Examination

The classic sign of placenta previa is painless, bright red bleeding; assess the amount and character of blood loss. Most often this bleeding occurs between 28 and 34 weeks when the lower uterine segment thins and the low implantation site is disrupted, but it may occur as early as 16 to 24 weeks. If heavy bleeding occurs at this point, there is over a 50% chance of pregnancy loss. With a marginal or low-lying placenta previa, the bleeding may not start until the patient is in labor. Assess the uterus for contractions; unless the patient is in labor, the uterus is relaxed and nontender. A vaginal examination should not be performed because even the gentlest examination can cause immediate hemorrhage.

Check the vital signs; note any symptoms of hypovolemic shock (restlessness; agitation; increased pulse; delayed capillary blanching; increased respirations; pallor; cool, clammy skin; hypotension; and oliguria). Monitor the baseline fetal heart rate and the presence or absence of accelerations, decelerations, and variability in the electronic fetal monitoring (EFM).

Ask if the patient feels the fetus move. Assess the fetal position and presentation by using Leopold maneuvers. Monitor the patient's contraction status, and palpate the fundus to determine the intensity of contractions. View the fetal monitor strip to assess the frequency and duration of the contractions; more often, the uterus is soft and nontender, unless the patient is in labor. Throughout the patient's hospitalization, continue to monitor for signs of hypovolemic shock and the amount and character of bleeding. Maintain continuous EFM until bleeding ceases; then, if hospital policy permits, monitor the fetus for 30 minutes every 4 hours.

Psychosocial

The heavy, bright red bleeding that often accompanies placenta previa is anxiety producing for the patients and significant others. The patients are concerned not only for themselves but also for the well-being of the infant. Determine the patients' support system because many of these patients have been on complete bedrest for an extended period of time. Assess the effect of prolonged bedrest on the patients' job, childcare, interpersonal, financial, and social responsibilities.

Diagnostic Highlights

General Comments: Vaginal examinations are contraindicated for a pregnant patient who is bleeding until a previa is ruled out by ultrasound visualization.

Test	Normal Result	Abnormality With Condition	Explanation
Transvaginal ultrasound (preferred); transabdominal ultrasound is also done	Placental implantation visualized in fundus of uterus	Placental implantation visualized in lower uterine segment	Visualization of placenta determines location and can rule out other causes of bleeding (e.g., abruption, cervical lesion, excessive show); transvaginal ultrasound can diagnose a placenta previa with 100% accuracy
Red blood cell count	3.6–5.8 mL/mm³	Decreases several hours after significant blood loss has occurred	Active bleeding causes decrease
Hemoglobin	11.7–17.3 g/dL	Decreases several hours after significant blood loss has occurred	Active bleeding causes decrease
Hematocrit	36%–52%	Decreases several hours after significant blood loss has occurred	Active bleeding causes decrease

Other Tests: Blood type and crossmatch; coagulation studies if bleeding is excessive

Primary Nursing Diagnosis ⬆ ⬇

Diagnosis

DiagnosisRisk for bleeding as evidenced by frank or occult hemorrhage, hypotension, and/or tachycardia

Outcomes

OutcomesBlood loss severity; Fluid balance; Hydration; Circulation status; Symptom severity; Symptom control; Vital signs

Interventions

InterventionsBleeding reduction; Blood product administration; Fluid resuscitation; Fluid monitoring; IV therapy; Shock management: Volume; Vital signs monitoring

Planning and Implementation ⬆ ⬇

PLANNING AND IMPLEMENTATION

Collaborative

Management of a patient with placenta previa depends on the admission status of the birthing parent and the fetus, the amount of blood loss, the likelihood that the bleeding will subside on its own, and the gestational age of the fetus. If both the birthing parent and the fetus are stable and the fetus is immature (less than 37 weeks), delivery may be put off and an IV infusion started with lactated Ringer solution. In addition, the patient is maintained on bedrest with continuous EFM. Closely monitor the fetal heart rate. If any signs of fetal distress are noted (flat variability, late decelerations, bradycardia, tachycardia), turn the patient to the left side, increase the rate of IV infusion, administer oxygen via face mask at 10 L/min, and notify the physician. Once the bleeding has ceased for 24 to 48 hours, the patient may be discharged to home on bedrest before delivery. This conservative treatment gives the preterm fetus time to mature. If the patient is in labor and a marginal placenta previa that is at least 10 mm from the cervical os is present, the practitioner allows the patient to labor and deliver vaginally, with careful surveillance of patient and fetal status throughout the labor. Postpartum, the patient will require oxytocics to prevent hemorrhaging, owing to the poor ability of the lower uterine segment to contract.

If fetal distress is present or if the patient has lost a significant amount of blood, an immediate cesarean section and, possibly, blood transfusions are indicated. If the patient delivers (vaginally or by cesarean), monitor the patient for postpartum hemorrhage because contraction of the lower uterine segment is sometimes not effective in compressing the uterine vessels that are exposed at the placental site. Although medication is not given to treat a previa, pharmacologic treatment may be indicated to stop preterm labor (if it is occurring and if bleeding is under control), enhance fetal lung maturity if delivery is expected prematurely, or prevent Rh disease, if the patient delivers. Patients with placenta previa have an increased chance of complications and hysterectomy.

Pharmacologic Highlights

Medication or Drug Class	Dosage	Description	Rationale
Magnesium sulfate	4–5 g IV loading dose, 1–2 g/hr of IV maintenance	Central nervous system depressant	Effective tocolytic, has fewer side effects than beta-adrenergic drugs; administered only if bleeding is under control and preterm labor is evident
Betamethasone (Celestone)	12 mg IM q 24 hr × two doses	Glucocorticoid	Hastens fetal lung maturity; given if delivery is anticipated between 24 and 34 wk
RhD immunoglobulin (RhoGAM)	1,500 IM within 72 hr (prepared by the blood bank)	Immune serum	Prevents Rh isoimmunizations in future pregnancies; given if birthing parent is Rh-negative and infant is Rh-positive

Independent

If the patient is actively bleeding and patient and fetus are stable, maintain the patient on bedrest in the lateral position (preferably left lateral) to maximize venous return and placental perfusion. Because the patient may be on bedrest for an extended period of time, comfort can be increased with back rubs and positioning with pillows. Provide diversional activities and emotional support. The nurse should make every attempt to explain the condition, treatment, and potential outcomes to the patient. Often, if a preterm delivery is unavoidable, a special care nursery nurse comes in and discusses what the birthing parent can expect to happen to the infant on admission to the neonatal intensive care unit.

Evidence-Based Practice and Health Policy

Chen, M., Liu, X., You, Y., Wang, X., Li, T., Lua, H., Qu, H., & Xu, L. (2020). Internal iliac artery balloon occlusion for placenta previa and suspected placenta accreta: A randomized controlled trial. Obstetrics & Gynecology, 135, 1112–1119.

The authors aimed to study the effect of intraoperative balloon occlusion of the internal iliac arteries in women with placenta previa and antenatally diagnosed with placenta accreta. Placenta accreta occurs when all or part of the placenta attaches abnormally to the uterine wall and is associated with placenta previa. They used a single center, randomized control design with 100 women, 50 assigned to a usual care group and 50 with intraoperative balloon catheter placement and occlusion of bilateral internal iliac arteries. The primary outcome was the number of packed red blood cell units transfused.
The numbers of packed red blood cells that were transfused were not significantly different in the two groups. Hospitalization costs and the number of postoperative fevers were significantly higher in the balloon group. The authors concluded that the balloon procedures did not improve outcomes for women with placenta previa and suspected placenta accreta.

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DRG Information ⬇