RNC-OB Assessment Practice Questions (120 Flashcards)

SBP ≥160 or DBP ≥110 mmHg is a Red trigger requiring immediate bedside evaluation by a provider (MD/CNM) and preparation for antihypertensive administration (e.g., Labetalol or Hydralazine) within 30-60 minutes. Rationale: These values represent the threshold for hypertensive emergency and increased stroke risk in pregnancy. Exam Tip: NCC emphasizes the distinction between Yellow (cautionary) and Red (urgent action) triggers. For BP, 150s/100s are often yellow, while 160/110 is always red.

Magnesium Sulfate is a CNS depressant that crosses the placenta. It can decrease FHR baseline variability and the frequency/amplitude of accelerations. Clinical Reasoning: While Mag Sulfate can blunt the NST, a persistently non-reactive test with minimal variability still requires further evaluation (BPP) to rule out worsening fetal status vs. medication effect. Distractor Alert: Do not assume a non-reactive NST is normal just because the patient is on Magnesium; it simply makes the test harder to interpret.

The withdrawal of the Parasympathetic Nervous System (PNS) and the activation of the Sympathetic Nervous System (SNS). Once cord compression is relieved, the baroreceptor stimulus (hypertension) ceases. The vagal tone is inhibited (PNS withdrawal), and the SNS works to rapidly restore the heart rate to baseline to maintain cardiac output. A slow or overshoot return to baseline may suggest a blunted SNS response, burgeoning acidosis, or autonomic instability.

Android pelvis. Found in ~20% of women, this male-type pelvis is highly predisposed to Cephalopelvic Disproportion (CPD). The narrow forepelvis and convergent side walls often lead to persistent Occiput Posterior (OP) positioning, deep transverse arrest, and a difficult forceps application if attempted. Strategy: If the exam question mentions a heart-shaped inlet and slow descent or narrow arch, prioritize Android as the answer.

The probe must be placed on the right hand or wrist (pre-ductal). This measures oxygenation of blood before it reaches the ductus arteriosus, reflecting the oxygen concentration being delivered to the brain and heart. The NRP/NCC target for SpO2 at 1 minute of life is 60%–65%. Note: It takes several minutes for a healthy term infant to reach 90%. Avoid over-oxygenating; target the specific minute-by-minute ranges.