OB Exam 2 Study Guide - Labor & Delivery Flashcards

Stages of Labor

First Stage: Latent Phase
- Definition & Duration: Onset of labor; represents the longest phase of labor and can last up to $2\,\text{weeks}$ (exact duration is unknown).
- Cervical Dilation: Ranges from $0\,\text{cm}$ to $5\,\text{cm}$ .
- Contraction Characteristics:
- Frequency: Every $5\,\text{min}$ to $30\,\text{min}$ .
- Duration: $30\,\text{seconds}$ to $45\,\text{seconds}$ .
- Intensity & Regularity: Irregular pattern with mild to moderate intensity.
- Maternal Characteristics: Scant amount of brownish discharge, pale pink mucus, or expulsion of the mucus plug, accompanied by early cervical dilation and effacement.
First Stage: Active Phase
- Definition & Cervical Dilation: Cervix dilates from $6\,\text{cm}$ to $10\,\text{cm}$ , dilating at an average rate of $1\,\text{cm/hr}$ , though progress can jump rapidly.
- Contraction Characteristics:
- Frequency: Every $3\,\text{min}$ to $5\,\text{min}$ .
- Duration: $40\,\text{seconds}$ to $90\,\text{seconds}$ .
- Intensity & Regularity: Becoming more regular, with moderate to strong intensity, culminating in complete dilation.
- Maternal Characteristics:
- Emotional state becomes increasingly serious with an inward focus.
- Experiences feelings of helplessness, severe anxiety, apprehension, and irritability.
- Pain intensifies severely, leading to feelings of being out of control and doubting the ability to continue labor.
- Physical manifestations include nausea, vomiting, increased bloody show, an active urge to push, increased rectal pain, and strong sensations of needing a bowel movement.
- Noted as the most difficult part of labor.
First Stage: Transition Phase
- Cervical Dilation: Ranges from $8\,\text{cm}$ to $10\,\text{cm}$ .
- Contraction Characteristics:
- Frequency: Every $2\,\text{min}$ to $3\,\text{min}$ .
- Duration: $45\,\text{seconds}$ to $90\,\text{seconds}$ .
- Intensity: Strong.
- Maternal Characteristics:
- Exhaustion, extreme restlessness, irritability, and vocal expressions of loss of control (e.g., stating "I can't do this").
- Nausea and vomiting.
- Increased rectal pressure accompanied by the sensation of needing a bowel movement.
- Re-emphasized as the absolute most difficult part of labor.
Second Stage
- Definition & Timeline: Begins at full cervical dilation ( $10\,\text{cm}$ ) and ends with the complete birth of the newborn.
- Key Processes: Active pushing, progressive fetal descent, and delivery of the infant.
- Maternal Characteristics & Care:
- Maternal pushing efforts directly lead to the birth of the baby.
- Nursing interventions focus on monitoring contractions, guiding pushing efforts, assessing for perineal lacerations, and providing physical and emotional comfort.
Third Stage
- Definition & Timeline: Begins immediately after the delivery of the baby and concludes with the complete delivery of the placenta.
- Key Processes:
- Placental separation and expulsion.
- Quantitative Blood Loss (QBL) measurement to track blood loss accurately.
- Placental Presentation Types:
- Schultze Presentation: The shiny fetal surface of the placenta emerges first ("shiny Schultze").
- Duncan Presentation: The dull, rough maternal surface of the placenta emerges first ("dull Duncan").
- Medications & Nursing Care:
- Administration of Oxytocin occurs immediately after the baby is out to stimulate uterine contraction, assist in placental expulsion, and manage Estimated Blood Loss (EBL).
- Care involves encouraging maternal pushing efforts, calculating the newborn's APGAR score, cleaning the infant, facilitating maternal-infant bonding, and monitoring for postpartum hemorrhage.
Fourth Stage
- Definition & Timeline: Postpartum recovery phase focused on maternal stabilization and return to physiological homeostasis.
- Maternal Characteristics: Re-establishment of vital sign homeostasis.
- Nursing Care: Providing comfort, performing fundal massage to ensure uterine contraction, evaluating lochia, and assisting or requiring the patient to urinate.

Nursing Care During Labor Stages

Assessment Measures (Latent and Active Phases)
- Leopold's Maneuvers: Performed to determine fetal presentation and positioning.
- Fetal Heart Tones (FHT): Fetal heart rate is best auscultated or monitored over the side where the baby's back is positioned.
- Comfort Interventions: Frequent maternal position changes, non-pharmacological comfort measures, and PRN pain medication/analgesics.

The Five Ps of Labor

Passenger: The fetus along with the placenta.
Passageway: The birth canal (maternal pelvis, cervix, vagina, and pelvic floor).
Powers: Involuntary uterine contractions driving cervical dilation, effacement, and fetal descent.
Position: Maternal physical positions and provider preferences/conditions during labor.
Physiological: Maternal emotional and psychological feelings during the labor process.

Labor Complications and Management

Prolapsed Umbilical Cord
- Definition: The umbilical cord becomes displaced, slipping ahead of the presenting part of the fetus or protruding directly through the cervix.
- Pathophysiology: Causes severe cord compression, resulting in compromised fetal circulation and hypoxia.
- Risk Factors: Rupture of amniotic membranes, abnormal fetal presentation, and transverse fetal lie.
- Emergency Management:
- Reposition the mother (e.g., knee-chest or Trendelenburg position).
- Insert a sterile gloved hand into the vagina to manually push the fetal presenting part up and off the cord.
- Apply a wet sterile rag soaked in sterile water over the exposed cord to prevent it from drying out.
Chorioamnionitis
- Definition: Bacterial infection of the chorion and amniotic sac (the most common intrapartum infection).
- Management: Monitor maternal fever continuously and administer IV antibiotics (specifically Ampicillin).
Fetal Distress
- Manifestations: Recurring fetal heart rate decelerations, specifically variable decelerations indicating significant fetal hypoxia.
- Immediate Intervention: Instantly discontinue Oxytocin infusion.
Precipitous Labor
- Definition: Labor and birth occurring rapidly in less than $3\,\text{hours}$ total.
- Characteristics: Extremely fast progression, higher incidence of excessive bleeding, and typically occurs in multiparous women (not a first-time mother).
- Management: Administer Magnesium Sulfate (while closely monitoring for toxicity), monitor for postpartum bleeding/hemorrhage, and immediately stop Oxytocin.
Shoulder Dystocia
- Definition: Occurs when the fetal anterior shoulder becomes impacted behind the maternal pubic bone, preventing delivery and cutting off circulation to the lower half of the baby.
- Clinical Sign: The "turtle sign" (fetal head emerges and then retracts tightly against the perineum).
- Sequential Emergency Management:
1. McRoberts Maneuver: Performed FIRST to hyperflex the mother's legs against her abdomen to flatten the sacrum and change pelvis shape.
2. Suprapubic Pressure: Applied SECOND directly over the pubic bone to dislodge and rotate the anterior shoulder.
- Fetal Complications: Hypoxia, brachial plexus injury (Erb's palsy), broken clavicle, and Cerebral Palsy (CP).
- Maternal Complications: Excessive blood loss, extensive perineal lacerations or episiotomy, symphyseal separation, and psychosocial trauma.

Operative Delivery, Interventions, and Birth Trauma

Forceps-Assisted Vaginal Birth
- Definition: Surgical instrument consisting of metal blades placed around the fetal head to assist with delivery.
- Indications: Maternal exhaustion, fetal distress, delivery of the head in breech presentation, and arrest of fetal head rotation.
- Prerequisites for Use:
- Cervix must be completely dilated ( $10\,\text{cm}$ ).
- Fetal presentation must be vertex (head first).
- Amniotic membranes must be fully ruptured.
- No Cephalopelvic Disproportion (CPD) present.
- Maternal Complications: Cervical, vaginal, and perineal lacerations; bladder injury; sulcus tears.
- Newborn Complications: Facial bruising, facial nerve palsy, cephalohematoma, and subdural hematoma.
- Nursing Responsibility: Continuously monitor Fetal Heart Rate (FHR).

Fetal Presentation, Position, Lie, and Station

Fetal Presentation
- Cephalic: Baby's head is positioned downward facing the cervix.
- Transverse: Baby lies horizontally across the maternal uterus.
- Breech: Baby's buttocks or feet are positioned downward toward the cervix.
Fetal Position
- LOA (Left Occiput Anterior): Fetal occiput/back faces toward the mother's left front ( $6\,\text{feet}$ position/anterior).
- ROA (Right Occiput Anterior): Fetal occiput faces toward the mother's right front.
- LOP (Left Occiput Posterior): Fetal occiput faces toward the mother's left back.
- ROP / ROOP (Right Occiput Posterior): Fetal occiput faces toward the mother's right back.
Fetal Lie
- Orientation of the fetal spine relative to the maternal spine: classified as either longitudinal or transverse.
Fetal Station
- Measurement of fetal descent into the maternal pelvis relative to the level of the ischial spines, ranging from $-5\,\text{cm}$ to $+5\,\text{cm}$ .

Pharmacological Agents in Obstetrics

Terbutaline
- Class: Tocolytic.
- Dosage & Route: $0.25\,\text{mg}$ delivered Subcutaneously ( $0.25\,\text{subQ}$ ).
- Indication: Temporarily stops uterine contractions.
- Nursing Consideration: Monitor closely for maternal tachycardia.
Betamethasone
- Class: Antenatal Corticosteroid.
- Indication: Promotes fetal lung maturation in preterm labor.
Magnesium Sulfate
- Class: Tocolytic / Neuroprotective Agent.
- Indication: Prevents fetal intraventricular brain bleeding in preterm labor; used in preeclampsia management.
Indomethacin
- Class: Nonsteroidal Anti-inflammatory Drug (NSAID) / Tocolytic.
- Indication: Decreases and stops uterine contractions.
Nifedipine
- Class: Calcium Channel Blocker / Tocolytic.
- Indication: Used in the management of preterm labor to stop contractions.
Oxytocin
- Class: Uterotonic / Pituitary Hormone.
- Indication: Induces or augments labor contractions; aids in third-stage placental expulsion and reduces blood loss.
Misoprostol
- Class: Prostaglandin.
- Indication: Softens the cervix (cervical ripening) and stimulates uterine contractions.
Carboprost
- Class: Uterotonic Prostaglandin.
- Indication: Controls postpartum hemorrhage.
- Side Effect: Causes severe diarrhea.
Methylergonovine (Methergine)
- Class: Uterotonic Ergot Alkaloid.
- Indication: Controls and stops severe postpartum bleeding.
- Contraindication: Do NOT administer to patients with hypertension.
Hemabate
- Class: Uterotonic Prostaglandin.
- Indication: Treats severe postpartum hemorrhage.
- Contraindication: Do NOT administer to patients with asthma.
Summary of Tocolytic Drugs
- Tocolytic agents (e.g., Terbutaline, Nifedipine, Indomethacin, Magnesium Sulfate) function to stop uterine contractions.

Placenta Abnormalities

Placenta Accreta
- Attaches deeply into the uterine myometrium wall and fails to separate normally after delivery.
Vasa Previa
- Occurs when fetal blood vessels run unsupported through the membranes over the cervical os.
- Succenturiate: Accessory double-lobed placenta.
- Battledore: Umbilical cord attaches to the margin/side of the placenta, causing an increased risk for fetal hemorrhage.
- Velamentous: Umbilical cord vessels insert into the fetal membranes rather than the placental mass.

Internal Fetal and Uterine Monitoring

Intrauterine Pressure Catheter (IUPC)
- Function: An invasive internal monitoring device used to objectively measure contraction strength, resting tone, and exact contraction metrics.
- Key Metrics Measured:
- F: Frequency
- D: Duration
- I: Intensity
- Prerequisites: Membranes must be ruptured and the cervix must be sufficiently dilated.
- Contraindications: Cannot be completed in cases of dystocia/disproportion.
- Nursing Considerations: Objective assessment of contraction strength cannot be known without an intravaginal catheter. Monitor maternal temperature hourly due to infection risk following membrane rupture.
Amnioinfusion
- Definition: Infusion of isotonic fluid into the amniotic cavity via an IUPC.
- Indications: Cord compression, oligohydramnios, and recurrent variable decelerations.
- Timing: Administered after artificial or spontaneous rupture of membranes.
- Fluids Used: Normal Saline (NS) or Lactated Ringer's (LR).
- Nursing Care: Monitor continuously for uterine overdistension.
Fetal Scalp Electrode (FSE)
- Definition: Direct internal fetal heart electrode attached to the fetal scalp for high-accuracy FHR readings.
- Placement Requirements: Applied only by a Registered Nurse (RN) after rupture of membranes.
- Indications: Used when external tracking is difficult due to maternal excessive movement or maternal obesity.
- Absolute Contraindications: Maternal HIV infection, active genital herpes, or maternal blood-borne infections.
- Complication: Risk of fetal scalp injury or scalp laceration.

Procedures: Amniotomy, Amnioinfusion, and VBAC

Cervical Assessment Definitions
- Dilation: Thinning and opening of the cervix measured in centimeters ( $0\,\text{cm}$ to $10\,\text{cm}$ ):
- $0\,\text{cm}$ : Closed cervix.
- $1\,\text{cm}$ to $9\,\text{cm}$ : Progressively opening.
- $10\,\text{cm}$ : Completely dilated and ready for pushing.
- Effacement: Shortening and thinning of the cervix measured in percentage ( $0\%$ to $100\%$ ):
- $0\%$ : Thick cervix.
- $50\%$ : Halfway thinned.
- $100\%$ : Completely thinned/effaced.
- Station: Descent of the fetal head relative to the maternal ischial spines ( $-5\,\text{cm}$ to $+5\,\text{cm}$ ):
- $0$ station: Fetal head is level with the ischial spines.
- Negative values ( $-1, -2, -3\,\text{cm}$ ): Fetal head is high above the ischial spines.
- Positive values ( $+1, +2, +3\,\text{cm}$ ): Fetal head is low below the ischial spines.
- $+4, +5\,\text{cm}$ : Fetal head is on the perineum, very close to delivery.
- Example Interpretation: An assessment of $8\,\text{cm}/90\%/+1$ indicates the cervix is $8\,\text{cm}$ dilated, $90\%$ effaced, and the fetal head is $1\,\text{cm}$ below the ischial spines.
Amniotomy (Artificial Rupture of Membranes - AROM)
- Definition: Surgical rupture of fetal membranes performed exclusively by a physician.
- Priority Nursing Action: Check fetal heart rate status immediately following rupture to rule out prolapsed cord.
- Infection Control: Monitor maternal temperature every $2\,\text{hours}$ post-rupture.
- Indications: Induction or augmentation of labor, assessment of amniotic fluid color/quantity, or facilitating placement of internal monitors (FSE or IUPC).
Vaginal Birth After Cesarean (VBAC)
- Selection Criteria: No history of prior uterine rupture, clinically adequate pelvis, and a non-recurring labor pattern.
- Contraindications: Large for Gestational Age (LGA) fetus, fetal malpresentation, Cephalopelvic Disproportion (CPD), or previous vertical (classical) uterine incision.
- Incision Type: Low transverse incision (dermatome) allows easier healing, reduced pain management term, and lower risk of rupture.

Labor Pain Management

Non-Pharmacological Methods
- Effleurage (light cutaneous massage).
- Sacral counterpressure.
- Hydrotherapy.
- Aromatherapy.
Pharmacological Methods
- Spontaneous Vaginal Delivery (SVD): Pudendal block ("P block") and Epidural analgesia.
- Low Transverse Cesarean Section (LTCS): Epidural anesthesia and General anesthesia.

Fetal Heart Rate Patterns, Decelerations, and Assessment

Tachysystole
- Definition: More than $5$ contractions in $10\,\text{minutes}$ averaged over a $30\,\text{minute}$ window.
- Pathophysiology: Cervix does not soften or relax between contractions; uterine resting tone is compromised.
- Dangers: Lack of uterine relaxation severely restricts uteroplacental blood flow, leading to potential fetal hypoxia and distress.
- Management: Discontinue Oxytocin immediately.
Deceleration Types and Nursing Interventions
- Variable Decelerations:
- Shape: Abrupt, "V"-shaped drop in FHR.
- Cause: Umbilical cord compression.
- Primary Intervention: Change maternal position.
- Late Decelerations:
- Timing: Occurs after the peak of the uterine contraction.
- Cause: Uteroplacental insufficiency (associated with maternal smoking, compromised placenta, or Intrauterine Growth Restriction [IUGR]).
- Risk: Prolonged fetal oxygen deprivation can cause permanent injury/special needs.
- LION Emergency Protocol:
  - L: Left lateral position change.
  - I: Increase IV fluid rate.
  - O: Administer Oxygen via non-rebreather mask at $10-15\,\text{L/min}$ .
  - N: Notify healthcare provider immediately.
  - (Action): If labor is being induced, stop Oxytocin immediately.
- Early Decelerations:
- Profile: Reassuring pattern, mirrored smoothly with contractions.
- Cause: Head compression as the baby drops into the birth canal.
- Primary Action: Perform a vaginal exam first (indicates head descent; cervix may be completely dilated).
FHR Accelerations and Baseline Metrics
- Accelerations: Not strictly required for a good trace, but defined by the standard rule: $15 \times 15 \times 2 \times 20$ ( $15\,\text{bpm}$ increase above baseline lasting for $15\,\text{seconds}$ , occurring $2$ times within a $20\,\text{minute}$ window).
- Normal Baseline FHR: $110\,\text{bpm}$ to $160\,\text{bpm}$ .
- Variability Classifications:
- Moderate / Average Variability: $6\,\text{bpm}$ to $25\,\text{bpm}$ fluctuation (reassuring).
- Minimal Variability: $< 6\,\text{bpm}$ fluctuation.
- Absent Variability: Undetectable baseline fluctuation (straight line; non-reassuring).

Maternal Pelvic Types

Gynecoid: Classic round shape; most favorable pelvic type for vaginal delivery, present in $50\%$ of women.
Platypelloid: Flat/oval shape; high probability of requiring a C-section, present in $5\%$ of women.
Android: Heart/wedge shape; results in slow exit from the birth canal, present in $20\%$ of women.
Anthropoid: Long oval shape; narrow outlet causing difficulty passing, present in $25\%$ of women.

Maternal Hypotension Management and Oxygen Administration

Maternal Hypotension Management
- Uncorrected hypotension causes fetal distress due to decreased placental perfusion.
- Interventions: Administer IV fluids, give fluid bolus with epidural administration, position changes with regular rest breaks, and offer apple juice.
Oxygen Administration Protocol
- Delivery Device: Non-rebreather face mask exclusively.
- Flow Rate: Set to $10-15\,\text{L/min}$ .
- Contraindications: Do NOT use a nasal cannula or Venturi mask for intrapartum fetal resuscitation.

Preeclampsia and Magnesium Toxicity

Preeclampsia Diagnostics & Symptoms
- Definition: Onset of hypertension occurring after $20\,\text{weeks}$ of gestation.
- Major Clinical Indicators: High blood pressure, severe headache, visual disturbances, and Right Upper Quadrant (RUQ) / epigastric pain.
Monitoring Requirements for Magnesium Therapy
- Monitor respiratory rate continuously.
- Monitor hourly urine output.
- Assess Deep Tendon Reflexes (DTRs).
- Track FHR and maternal BP.
Magnesium Toxicity Manifestations & Antidote
- Signs of Toxicity: Respiratory depression and absent or significantly decreased DTRs.
- Antidote: Administer Calcium Gluconate immediately.