Core Nursing Explanation
Key Concept Analysis: This question tests the priority nursing action for a patient presenting with a classic sign of
Placenta previa in the third trimester. The key features are
sudden, painless, bright red vaginal bleeding after 20 weeks of gestation. The pathophysiological mechanism is that the placenta implants in the lower uterine segment, covering or lying near the internal cervical os. Any cervical change or uterine activity can cause the placenta to separate from the uterine wall, leading to painless hemorrhage. The priority is always to assess and stabilize the mother first, as maternal well-being is essential for fetal survival.
Answer Rationale:
Key Point! The priority nursing assessment is to
Assess the amount and characteristics of vaginal bleeding. This is the first step in the nursing process (Assessment) for any bleeding emergency. Quantifying the blood loss (e.g., saturating how many pads per hour) and noting the color (bright red indicates active, arterial bleeding) provides critical data to determine the severity of the hemorrhage, guide immediate interventions (e.g., IV fluids, oxygen, preparing for possible cesarean delivery), and establish a baseline for ongoing monitoring. The patient's stable vital signs and reassuring fetal heart rate (FHR) are positive signs, but they do not negate the need for immediate and continuous bleeding assessment.
Distractor Analysis:
Watch out for confusion! Option ①, performing a sterile vaginal examination (SVE), is
contraindicated when placenta previa is suspected. A digital exam can cause catastrophic hemorrhage by further disrupting the implanted placenta. Diagnosis is confirmed by ultrasound, not physical exam.
Option ③, obtaining a urine specimen, is a routine prenatal assessment but is not the priority in an acute bleeding scenario. While a urinary tract infection (UTI) can cause bleeding, the presentation of sudden, painless bright red bleeding is far more characteristic of an obstetric cause.
Option ④, measuring fundal height and fetal position, is an important part of antenatal assessment but is secondary to assessing active bleeding. Furthermore, in placenta previa, the fundus is often soft and non-tender, and the fetus may be in a breech or transverse lie due to the placenta occupying the lower uterine segment.
Related Concepts: This scenario must be differentiated from
Abruptio placentae (placental abruption), which typically presents with
painful dark red bleeding, a rigid/tender uterus, and signs of fetal distress. The nursing priority in abruption is also maternal stabilization, but the clinical presentation is distinct. The management for both conditions involves maternal resuscitation, continuous FHR monitoring, and preparation for possible emergency delivery.
Concept Summary
| Condition | Key Feature | Priority Nursing Action | Critical Contraindication |
|---|
| Placenta Previa | Painless, bright red bleeding in 2nd/3rd trimester | Assess bleeding; Monitor VS & FHR; Prepare for possible C-section | NO vaginal exam |
| Abruptio Placentae | Painful, dark red bleeding; rigid/tender uterus | Assess bleeding & pain; Monitor for concealed hemorrhage & shock; Prepare for emergency delivery | Delay can lead to DIC (Disseminated Intravascular Coagulation) |
Side-by-Side Comparison!
| Assessment | Placenta Previa | Abruptio Placentae |
|---|
| Bleeding | Bright red, painless, visible | Dark red, painful, may be concealed |
| Uterine Tone | Soft, non-tender | Firm, board-like, very tender |
| Fetal Presentation | Often malpresentation (breech/transverse) | Often normal presentation |
| Shock | Proportional to visible blood loss | May be disproportionate (concealed hemorrhage) |
| Coagulopathy Risk | Lower | High risk for DIC |
Anatomy, Physiology & Pharmacology Points
The lower uterine segment is poorly contractile after delivery, which is why placenta previa carries a high risk for
Postpartum hemorrhage (PPH). Pharmacological management may include
tocolytic agents (like terbutaline) to stop contractions and delay delivery if the fetus is preterm, and
corticosteroids (betamethasone) to accelerate fetal lung maturity. The definitive treatment for a major previa is
cesarean delivery.
Memory Tips
Previa = Painless (both start with 'P').
Abruption = Agony (painful). Remember: "No fingers in the previa!" to recall the absolute contraindication of a vaginal exam.
High-Frequency NCLEX Topics
NCLEX loves to test the differentiation between placenta previa and abruption, and the corresponding priority nursing actions and contraindications. Knowing that a vaginal exam is forbidden in previa is a classic "safety" question.
Watch Out for Question Variations!
The same concept can be tested by: 1) Asking for the
priority diagnosis (Risk for fluid volume deficit). 2) Asking which action the nurse should take
first after assessing bleeding (e.g., start two large-bore IV lines). 3) Presenting a scenario of
abruptio placentae and asking for the priority assessment (pain and uterine tone).