High-Risk Pregnancy & Delivery – Comprehensive Lecture Notes

Placenta Previa

• Definition: Placental implantation in the lower uterine segment, covering (complete), partially covering, or lying close to (low-lying) the cervical os.
• Types
  • Complete – placenta entirely covers internal os.
  • Partial – placenta partially covers os.
  • Low-lying – placenta implanted in lower segment but not covering os.
• Incidence: 0.5\% of all births.
• Risk Factors
  • History of placenta previa.
  • Uterine scar (prior cesarean, myomectomy).
  • Induced abortion with curettage.
  • Multiple gestation (larger placental mass).
  • African- or Asian-American ethnicity.
  • Cigarette smoking, cocaine use.
• Classic Clinical Picture
  • Painless bright-red vaginal bleeding in 3rd trimester (≈70\%).
  • Soft, non-tender uterus with normal tone.
  • Fetal malpresentation common (breech, transverse) because placenta occupies lower pole.
  • 20\% experience bleeding only with contractions.
• Diagnosis
  • Ultrasound (transabdominal → transvaginal if needed) accuracy 93–97\%.
  • NO vaginal examinations until previa excluded.
• Management Principles
  • Immediate evaluation of bleeding; avoid digital exam.
  • Continuous FHR & maternal vitals.
  • Labs: CBC/H&H, coagulation, type & cross (blood ready).
  • IV access, fluids; Rh-negative → Rh-D immune globulin.
  • Betamethasone 12\,\text{mg IM q12h \times 2} for fetal lung maturity if <34 wks.
  • Delivery usually cesarean once bleeding becomes heavy/uncontrollable or at fetal lung maturity (~36–37 wks).
• Expectant (Conservative) Management Case (33 wks)
  • Criteria: stable mom, minimal bleeding, reassuring FHR, preterm.
  • Orders: q2 wk US, daily pad count, weekly NST, H&H weekly, IV heplock (allows rapid infusion if hemorrhage while reducing activity), complete bedrest, no vaginal exams, betamethasone repeat in 7 days if undelivered.
  • Nursing considerations
    • Monitor H&H to trend occult blood loss/need for transfusion.
    • Assess for tachycardia, orthostatic changes as early hypovolemia markers.
    • Evaluate pad counts for concealed bleeding; weigh pads (1 g ≈ 1 mL).

Placental Abruption (Abruptio Placentae)

• Definition: Premature separation of normally implanted placenta after 20 wks.
• Types (by placental surface involvement)
  • Marginal – blood escapes vaginally (external bleeding).
  • Central – concealed hemorrhage; separation central, edges intact.
  • Complete – total separation with massive bleeding.
• Etiology/Risk Factors
  • Hypertension/preeclampsia (vasospasm).
  • Trauma (MVC, domestic violence, falls).
  • Cocaine/methamphetamine → vasoconstriction.
  • Sudden uterine decompression (polyhydramnios rupture).
  • Smoking, thrombophilias, previous abruption, under-nutrition.
• Classic Signs & Symptoms
  • Dark-red bleeding (may be scant if concealed).
  • Severe abdominal/uterine pain; rigid, board-like uterus.
  • Hypertonic, high-frequency contractions; uterus fails to relax.
  • Non-reassuring FHR: late decels, decreased variability, tachy/bradycardia.
• Maternal/Fetal Risks
  • Maternal: hypovolemic shock, DIC, renal failure, death.
  • Fetal: asphyxia, prematurity, demise.
• Diagnostic & Monitoring
  • Ultrasound & Biophysical Profile (BPP) – may miss small abruptions.
  • Labs: CBC/H&H, clotting studies, fibrinogen, platelets, PT/PTT; type & cross.
  • Continuous EFM; strict I&O, urine output >30 mL/hr; CVP line if severe.
• Clinical Therapy
  • Stabilize cardiovascular status: two large-bore IVs, LR/NS, possible whole blood.
  • Immediate birth if term, severe bleeding, or non-reassuring fetal status (usually cesarean unless coagulopathy).
  • Rh-D immune globulin if Rh-negative.
• Case (35 wks, G1P0, HTN, smoker, underweight)
  • Contributing factors: chronic hypertension, malnutrition, smoking craving (vasoconstriction), possible anemia.
  • Indwelling Foley: accurate hourly output (renal perfusion, DIC).
  • IV fluids 1000\,\text{mL RL @ 75 mL/hr}: maintain intravascular volume, prevent shock.
  • Serial US qOD: monitor placental status, fetal growth, fluid.
  • Treatment differs from previa: in abruption vaginal exams allowed; priority is rapid stabilization & possible urgent delivery; placenta previa focuses on avoiding labor & hemorrhage control.

Placenta Accreta Spectrum

• Accreta – chorionic villi attach to myometrium.
• Increta – invade myometrium.
• Percreta – penetrate serosa ± adjacent organs.
• Risks: previous cesarean (risk ↑ with each CS), placenta previa, uterine curettage.
• Complications: massive postpartum hemorrhage, retained placenta, need for cesarean hysterectomy.

Cervical Insufficiency (Incompetent Cervix)

• Definition: painless, passive cervical dilation in 2nd trimester (usually <24 wks) → recurrent fetal loss.
• Etiology: congenital (DES exposure), trauma (forceps, D&C), cervical surgery (cone biopsy, LEEP), hormonal influences.
• Presentation: painless bleeding or pressure, shortened cervix on US.
• Diagnosis: history + transvaginal US cervical length <25 mm before 24 wks.
• Treatment: Cerclage (McDonald, Shirodkar) placed 12–14 wks; removed 37 wks or at labor/ROM.
• Teaching: report contractions, ROM, bleeding, infection.

Preterm Labor (PTL)

• Definition: labor before 37 0/7 wks.
• Risk Factors
  • Infections (UTI, BV, chorio), diabetes, HTN.
  • Extremes of age (
  • Smoking, drugs, domestic violence, uterine anomalies.
• Health Promotion – Warning Signs
  • Contractions q≤10 min, menstrual-like cramps.
  • Pelvic pressure, low dull backache.
  • ROM or change in discharge, abdominal cramps ± diarrhea.
• Assessment & Diagnostics
  • Cervical length: normal 4–5 cm; shortened → risk.
  • Fetal Fibronectin (fFN) swab between 24–34 wks; presence predicts labor within 2 wks; collect before SVE, intercourse prohibited 24 h.
  • Salivary estriol every 2 wks × 10 wks (research use).
• Tocolysis
  • Magnesium sulfate
    • Load 4 g over 30 min, maint 2 g/h.
    • Competes with Ca²⁺, relaxes uterus.
    • Toxicity: absent DTRs, UO<30 mL/h, RR<12, hypotension; antidote Calcium gluconate 1 g IV.
  • Others (not in slides): nifedipine, indomethacin, terbutaline.
• Corticosteroids: Betamethasone 12 mg IM q12h × 2; or Dexamethasone 6 mg IM q12h × 4 to mature lungs.

Premature / Prolonged Rupture of Membranes (PROM, PPROM)

• PROM: rupture before labor; PPROM: <37 wks.
• Etiology often infection; risk ↑ if ROM >24 h.
• Management
  • Hospitalize, observe infection (temp, WBC, uterine tenderness).
  • Betamethasone for lung maturity if <34 wks.
  • Avoid digital exams; collect cultures.

Gestational Diabetes Mellitus (GDM) – Intrapartum

• Timing & Mode
  • Generally deliver at term; elective induction 38–39 wks once lungs mature (phosphatidylglycerol +).
  • Cesarean rate ≈45\% (macrosomia, shoulder dystocia).
• Intrapartum Care
  • IV fluids with glucose + regular insulin IV drip; hourly capillary BG maint 70–110 mg/dL.
  • Continuous EFM; anticipate shoulder dystocia.
• Fetal Macrosomia
  • Birth wt >4000 g.
  • Risks: maternal DM, post-term, obesity, genetics.
  • Complications: shoulder dystocia, operative birth, PPH, infection.
  • Shoulder Dystocia Maneuvers
    • McRoberts (hyperflex hips), suprapubic pressure.
    • Gaskin (hands-knee), NO fundal pressure.
    • Possible episiotomy extension, vacuum, Zavanelli (replace head) → CS.
• GDM Case (Screening 1-h OGTT 152 mg/dL)
  • Risk factors: age >25 (34 y), prior stillbirth, possible unrecognized insulin resistance.
  • Diagnostic test likely 3-h 100 g OGTT after abnormal 1-h screen.
  • Normal 1-h screen cutoff <140 mg/dL (per ACOG), so 152 is positive.
  • Risks: maternal – preeclampsia, CS, T2DM later; fetal – macrosomia, hypoglycemia, RDS, IUFD.

Hypertensive Disorders of Pregnancy

• Categories
  • Chronic HTN: BP \ge 140/90 before pregnancy /
  • Gestational HTN: HTN after 20 wks without proteinuria, resolves <6 wks pp.
  • Preeclampsia: HTN with systemic involvement after 20 wks. Proteinuria no longer required but common.
  • Eclampsia: preeclampsia + seizures/coma.
  • Chronic HTN w/ superimposed preeclampsia.
• Preeclampsia Pathogenesis
  • Abnormal trophoblastic invasion → narrow, high-resistance spiral arteries → endothelial dysfunction, vasospasm, ↑ sensitivity to pressors, platelet activation.
  • Possible genetic, immune, prostaglandin imbalance.
• Diagnostic Criteria (ACOG 2020)
  • BP \ge140/90 twice \ge4 h apart after 20 wks.
  • PLUS one of: proteinuria (>$300 mg/24 h), platelets
• Severe Features
  • BP \ge160/110, plts
• Labs: CBC, CMP (LFTs, Cr), uric acid, magnesium, coagulation profile, 24-h urine, type & screen, fetal testing (NST, CST, BPP, Doppler).
• Hospital Management
  • Goal DBP 90–100 mmHg (hydralazine, labetalol).
  • Bed rest L lateral, high-protein low-Na diet, strict I&O, seizure precautions.
  • Magnesium sulfate prophylaxis: load 4–6 g over 30–60 min, maint 2–4 g/h; therapeutic level 4–8 mg/dL.
  • Betamethasone if <34 wks.
  • Delivery: after 34 wks or earlier for worsening disease or non-reassuring fetus.
• Eclampsia Management
  • During seizure: protect airway, left side, O₂ mask 8–10 L, suction, note time.
  • Post-ictal: assess cervix/labor, FHR, start/maintain magnesium, antihypertensives.
• HELLP Syndrome
  • Hemolysis, Elevated Liver enzymes, Low Platelets (<100k).
  • Present with malaise, N/V, RUQ pain; can occur without HTN.

Prolapsed Umbilical Cord

• Definition: cord lies below presenting part after ROM.
• Risk Factors: malpresentation, high head, long cord, PPROM, polyhydramnios, previa, multiples.
• FHR: acute bradycardia or variable decelerations.
• Nursing Actions (OB Emergency)
  • Call for help, elevate presenting part with sterile gloved hand.
  • Knee-chest or Trendelenburg position; administer O₂ 10 L mask.
  • Cover exposed cord with warm sterile saline gauze.
  • Prepare for stat cesarean; keep fingers lifting head until incision.

Uterine Rupture

• Types: complete (all layers), incomplete (dehiscence of prior scar).
• Etiology: previous classical CS scar, trauma, hyperstimulation, obstructed labor, VBAC.
• Early Sign: non-reassuring FHR (late decels, brady) followed by tearing uterine pain, loss of station, palpation of fetal parts.
• Maternal shock: tachycardia, hypotension, pallor.
• Management: emergent laparotomy & birth, hysterectomy possible, blood products.

Amniotic Fluid Embolism (Anaphylactoid Syndrome of Pregnancy)

• Incidence 1:20\,646; maternal mortality 26.4\% (≈10\% of all maternal deaths).
• Pathophysiology: amniotic fluid/fetal debris enter maternal circulation → pulmonary vaso-occlusion & anaphylactoid reaction.
• Predisposing: abruption, uterine rupture, intense uterine pressure.
• Clinical Triad
  • Respiratory distress: restlessness → dyspnea, cyanosis, ARDS.
  • Circulatory collapse: tachycardia, hypotension → cardiac arrest.
  • Coagulopathy: DIC, bleeding from IV sites, uterine atony.
• Nursing & Medical Management
  • O₂ 100\%, intubate, CPR, maintain hemodynamics (vasopressors), massive transfusion protocol.
  • Prepare for perimortem cesarean within 5 min if maternal arrest.

Ethical & Practical Connections

• High-risk conditions demand interdisciplinary teamwork (OB, anesthesia, neonatology, blood bank).
• Informed consent & patient education vital: bedrest implications, steroid purpose, magnesium effects.
• Cultural competence: smoking cessation support, dietary counseling respecting socioeconomic status.
• Resource allocation: availability of blood products, NICU beds, maternal transport decisions.

Quick Reference – Drug Dosages & Numbers

• Betamethasone: 12\,\text{mg IM q12h × 2} doses (repeat in 7 days if undelivered).
• Magnesium sulfate: load 4–6 g/30–60 min → maint 2–4 g/h; therapeutic 4–8 mg/dL.
• fFN window: 24–34 wks.
• Macrosomia: >4000 g; shoulder dystocia incidence 0.24–2\%.
• HELLP platelets: <100,000. Severe preeclampsia BP ≥160/110.
• Placenta previa incidence 0.5\%; painless bleed 70\%.
• AFE mortality 26.4\%.

Study Tips

• Differentiate placenta previa vs abruption: painless bright red vs painful dark red & rigid uterus.
• Recognize early non-reassuring FHR patterns; correlate with possible cord, abruption, rupture.
• Memorize critical drug antidotes: Ca-gluconate for Mg toxicity.
• Understand timing of corticosteroids (24–34 wks, effect 24–48 h) and repeat schedules.
• Practice scenario-based questions: prioritize actions (e.g., elevate part in cord prolapse before calling provider).