Comprehensive Obstetric Nursing: Fetal Monitoring, GTPAL, and High-Risk Gestational Conditions

Fetal Heart Tone Monitoring and the Nonstress Test (NST)

• Nonstress Test (NST) Fundamentals

  • An NST is a diagnostic procedure typically performed in later terms for normal pregnancies to visualize fetal heart tones and their reaction in utero.

  • For patients with complications—such as gestational diabetes, a history of hypertension, or pre-existing diabetes—the provider may order NSTs earlier in the pregnancy.

  • A typical NST lasts approximately $20$ minutes in duration to provide an adequate window for assessing fetal reactivity.

• Fetal Monitoring Strip Structure

  • The monitor uses radiographic paper similar to an EKG strip.

  • The monitoring setup consists of two separate sensors:

    • Transducer (Ultrasound): Placed externally to locate and track fetal heart tones. It is best positioned over the baby's back or head depending on fetal lie.

    • Tachometer: A monitor with a small internal bump used to measure the timing and frequency of uterine contractions.

  • Unified Assessment: Clinical staff must assess heart tones and contractions together. The goal is to ensure the fetus can tolerate uterine contractions, as contractions temporarily constrict blood supply and oxygenation.

  • External monitors can pick up maternal movement, sneezing, laughing, vomiting, or pushing, which may appear as "blips" or arrows on the strip.

• Fetal Heart Rate (FHR) Parameters

  • Normal Baseline: The standard range for fetal heart tones is $110-160\,bpm$.

  • Baseline Determination: The baseline is determined by looking at a period of time (usually $10$ minutes) absent of accelerations or decelerations.

  • Nervous System Control: Fetal heart tones are regulated by the parasympathetic and sympathetic nervous systems.

    • In preterm babies (less than $34$ weeks), the neurological system is immature. The parasympathetic system often dominates, leading to a higher heart rate and minimal variability.

    • As the sympathetic nervous system matures, it competes with the parasympathetic system, resulting in the characteristic "fluctuations" or variability that indicate an intact neurological system.

• NICHD Guidelines for Fetal Monitoring Categories

  • Category One (Reassuring): This indicates the strip is within normal limits. It requires a baseline of $110-160\,bpm$, moderate variability, and no concerning decelerations.

  • Category Two (Indeterminate): This requires increased monitoring and communication with the provider to ensure progression remains safe.

  • Category Three (Abnormal): Indicates an immediate need for the provider to come to the unit as an emergency or significant complication is occurring.

• Variability and Accelerations

  • Variability: The beat-to-beat fluctuation within a $10$-second window (each small square on the strip represents $10$ seconds).

    • Minimal: Less than $5\,bpm$ fluctuation.

    • Moderate: $10-25\,bpm$ fluctuation (this is the ideal/reassuring state).

    • Marked: Significant fluctuations; potentially indicates fetal excitement or, rarely, Rh incompatibility.

    • Absent: No detectable fluctuation; may occur during fetal sleep, preterm status, or if the mother has received depressants/narcotics.

  • Accelerations: Increases in the FHR above the baseline.

    • Criteria: Must be at least $15\,bpm$ above baseline for $15$ seconds (often referred to as $15 \times 15$ in term babies, though the instructor mentions a $20\,bpm$ increase in the example).

    • Prolonged Acceleration: An acceleration that lasts greater than $2$ minutes.

  • Decelerations: Drops in FHR below the baseline.

    • Prolonged Deceleration: A drop lasting greater than $2$ minutes; of much higher clinical concern than prolonged accelerations as it indicates oxygen deprivation.

Gestational History Nomenclature: GTPAL

• Gravida (G): Total number of pregnancies, regardless of outcome.

  • Primigravida (Prima): A first-time pregnancy.

• Term (T): Number of births occurring at $37$ weeks or later.

• Preterm (P): Number of births occurring between $20$ and $36$ weeks.

• Abortion (A): Number of pregnancies lost before $20$ weeks (the age of viability), whether spontaneous (miscarriage) or elective.

• Living (L): Number of currently living children.

• Practice Scenarios Provided:

  1. Patient 1: Currently pregnant, one previous full-term birth, one miscarriage at $10$ weeks.

     • Status: $G3, T1, P0, A1, L1$

  2. Patient 2: Two preterm births ($32$ and $35$ weeks), one term birth, all children living.

     • Status: $G3, T1, P2, A0, L3$

Hypertensive Disorders and Preeclampsia

• Pathophysiology of Preeclampsia

  • Characterized by vasoconstriction and the release of proteins into the circulatory system.

  • Endothelial Damage: Proteins cause damage to the endothelial walls of the vasculature, allowing protein to leak into the extrasensural space. Since fluid follows protein, this leads to significant edema.

• Clinical Signs and Symptoms

  • Headache: Usually severe and unresolved by Tylenol.

  • Visual Disturbances: Blurred vision, seeing "spots" (scotoma), "floaties," or dizziness.

  • Edema: Swelling in the hands and face. Dependent edema (swollen feet/legs) is normal in pregnancy, but preeclamptic edema does not resolve with rest or elevation.

  • Weight Gain: Gaining more than $5$ pounds in a single week.

  • Epigastric Pain: Pain in the upper right quadrant (liver involvement).

• Assessment Techniques

  • Reflexes: Testing for hyperreflexia (e.g., $+3$ or $+4$). Brachial reflexes can be tested if an epidural prevents patellar testing. The instructor uses the bell of a stethoscope to tap the tendon in the brachial arch.

  • Clonus: Tested by dorsiflexing the foot towards the knee. A positive result is indicated by rhythmic "beats" or jerking of the foot upon release. Documented as one, two, or three beats of clonus.

• Magnesium Sulfate Therapy

  • Indication: Administered via IV infusion to prevent eclamptic seizures.

  • Mechanism: Inhibits neural synapses to relax the nervous system.

  • Nursing Risks: It is a critical medication. Overload can lead to hypermagnesemia, which decreases respiratory drive and level of consciousness.

  • Antidote: Calcium Gluconate must be readily available at the bedside.

• HELLP Syndrome

  • A severe complication of preeclampsia involving:

    • H: Hemolysis (breakdown of red blood cells).

    • EL: Elevated Liver enzymes.

    • LP: Low Platelets.

  • Risk: High risk for Disseminated Intravascular Coagulation (DIC).

Hemorrhagic Complications: Early vs. Late Pregnancy

• Early Pregnancy Bleeding

  • Spontaneous Abortion: Generally cannot be stopped once begun; often due to congenital anomalies incompatible with life. Requires psychological support.

  • Ectopic Pregnancy: Implantation in the fallopian tube. High risk of rupture and internal hemorrhage; constitutes a medical emergency requiring immediate surgical or medical intervention.

  • Gestational Trophoblastic Disease (Mole): Over-multiplication of sperm/ovum leading to inanimate, "grape-like" tissue. hCG levels are extremely high and abnormal. Can result in significant bleeding.

  • Dilation and Curettage (D&C): A procedure used to remove products of conception. Uses a curette (described as looking like a "banjo" with teeth) to scrape the uterine wall.

• Late Pregnancy Bleeding

  • Placenta Previa: Placenta implants over or near the cervical os.

    • Key Feature: Painless, bright red vaginal bleeding.

    • Management: Risk of massive hemorrhage ($700\,mL/min$ blood flow through the uterus). Requires C-section; vaginal exams are contraindicated.

  • Placental Abruption: Premature separation of the placenta from the uterine wall.

    • Key Feature: Extreme pain, rigid/board-like abdomen, and dark red bleeding (may be concealed).

    • Causes: Hypertension, blunt trauma (car accidents), and substance use (cocaine/methamphetamines causing severe vasoconstriction).

Medical Conditions in Pregnancy

• Diabetes (Gestational and Pre-gestational)

  • Increased maternal glucose crosses the placenta, causing the fetal pancreas to produce insulin, acting as a growth hormone.

  • Macrosomia: Large for Gestational Age (LGA) babies (e.g., $14$ pounds).

  • Polyhydramnios: Excessive amniotic fluid, often associated with poorly controlled maternal diabetes.

• Cardiac Disease

  • Pregnancy increases blood volume by $30-50\%$. Class III and IV heart disease patients (NYHA classifications) are at high risk.

  • Labor Management: Patients with severe heart disease cannot push (Valsalva maneuver), as it can trigger a fatal cardiac event. They often require "passive descent" and assisted delivery with forceps or vacuum extraction.

• Hyperemesis Gravidarum

  • Uncontrollable vomiting past the normal morning sickness phase, leading to weight loss, dehydration, and electrolyte imbalance. May require PICC lines and TPN (Total Parenteral Nutrition).

Ethical, Legal, and Cultural Considerations

• Implicit Bias: Healthcare providers must check biases regarding substance use or socioeconomic status to provide compassionate care, especially at county hospitals like Parkland.

• Interpersonal Violence (IPV): In Texas, IPV against a pregnant adult is NOT a mandatory reportable offense unless the patient is a minor (under $18$) or an elder. Reporting against the patient's will can put them in greater danger.

• Minor Status: A $16$-year-old who is pregnant is often legally treated as an adult for medical decision-making regarding the pregnancy.

• Religious Beliefs: Mention of a case involving a Jehovah’s Witness with HELLP syndrome who bled out because blood products could not be administered, highlighting the intersection of ethics, law, and emergency medicine.

Fetal Assessment and Screening

• Kick Counts: Patients are taught to monitor fetal movement at the same time each day, usually after eating or drinking water.

• Biophysical Profile (BPP): A $10$-out-of-10 or $12$-out-of-12 scoring system combining ultrasound and NST to assess fetal well-being based on movement, tone, breathing, and amniotic fluid volume.

• Chorionic Villus Sampling (CVS): Invasive genetic testing done early in pregnancy to check for congenital anomalies.

• NIPT: Non-invasive prenatal testing (DNA screening) via maternal blood.