Placental Insufficiency, APH, and IUGR Lecture Notes

Shared Pathophysiology & Integrated Overview

  • Placental Insufficiency = common root problem
    • Chronic maternal disorders ⟶ impaired uteroplacental blood flow.
    • Inadequate oxygen / nutrient transfer triggers a cascade of obstetric complications.
  • Risk cascade (illustrative chain)
    • Chronic hypertension ⟶ ↑\uparrow risk of IUGR.
    • IUGR ⟶ ↑\uparrow risk of still-birth, APH, need for intervention.
    • Either hypertension or IUGR ⟶ ↑\uparrow likelihood of placental abruption (major aetiology of APH).
  • Classic clinical scenario (example)
    • Woman with long-standing hypertension develops placental hypoperfusion ⟶ fetus becomes growth-restricted ⟶ unstable placenta separates prematurely ⟶ presents with antepartum bleeding.
  • Surveillance elements overlapping all three conditions
    • Maternal BP, urinalysis, routine labs.
    • Fundal-height plotting or serial growth scans.
    • CTG / kick-count education.
    • Repeated ultrasound (biometry, liquor, Dopplers, placental site).
    • Early referral and shared care with obstetrics, radiology & neonatology.
    • Anticipatory birth planning: timing, mode, neonatal unit alert, postpartum de-brief.

Ante-partum Haemorrhage (APH)

  • Definition
    • Bleeding from genital tract after ≥20 weeks\ge 20\ \text{weeks} and before delivery.
  • Main causes
    • Placenta praevia (low-lying / covering os).
    • Placental abruption (premature separation).
    • Vasa praevia (unprotected fetal vessels in membranes).
    • Local lesions/infections (e.g.
    • Cervical ectropion
    • Minor capillary breaks post-coitus).
  • Clinical significance
    • Maternal: haemorrhage, hypovolaemic shock, emergency hysterectomy.
    • Fetal: hypoxia, exsanguination (vasa praevia), preterm birth, perinatal death.
  • Communication & support
    • Stay calm, reassure – “Bleeding can be serious; we’ll get you and baby checked quickly.”
    • Encourage support person.
    • Clarify no vaginal exam until placental location known.
    • Validate fear, provide ongoing emotional support.
  • Immediate assessments
    • Amount/colour of loss, presence of clots.
    • Pain pattern (constant vs cramping) & uterine tone.
    • Fetal movements; escalate ↓ movements.
    • Maternal observations: HR, BP, RR, temperature, cap-refill.
    • Time of call / onset recorded precisely.
  • Documentation & hand-over
    • ISBAR to secondary care.
    • Record advice, actions, woman’s responses.
  • Inter-professional liaison
    • Obstetric registrar / consultant: definitive management.
    • Radiology: urgent scan for placental site ± abruption signs.
    • Ambulance: heavy bleed or maternal instability.
    • Neonatology: potential preterm / compromised neonate.
  • Pathophysiology summaries
    • Abruption: decidual vessel rupture ⟶ retro-placental clot ⟶ separation ⟶ fetal hypoxia + maternal bleed.
    • Praevia: inability of LUS placenta to stretch in 3rd trimester ⟶ marginal sinuses shear when cervix effaces or contracts.
  • Key risk factors
    • Chronic / gestational hypertension.
    • Previous CS or uterine surgery.
    • Smoking, cocaine or amphetamine use, trauma, multiple gestation, advanced age.

Intra-uterine Growth Restriction (IUGR) / Small for Gestational Age (SGA)

  • Definitions
    • SGA: estimated fetal weight (EFW) <10^{th}\ \text{percentile} for gestational age.
    • IUGR: pathologic failure to reach growth potential, usually due to placental insufficiency; may show abnormal Doppler flow or oligohydramnios.
  • Fetal / neonatal risks
    • Still-birth, intrapartum hypoxia.
    • Preterm induction / Caesarean.
    • Hypoglycaemia, hypothermia, NEC, sepsis.
    • Long-term: metabolic syndrome, neuro-developmental delay.
  • Maternal / psychosocial impact
    • Heightened anxiety, guilt, need for frequent appointments, possible prolonged hospitalisation.
  • Communication & support
    • Use simple, balanced language: “Baby is smaller; extra tests ensure well-being.”
    • Encourage questions, include whānau, offer continuity of caregiver.
    • Explain surveillance plan and potential for early delivery.
  • Assessments & monitoring
    • Symphyseal-fundal height each visit plotted on customised chart.
    • Daily fetal movement awareness education.
    • Serial ultrasound (growth every 2–3 wks), amniotic fluid index, umbilical/MCA Dopplers.
    • Maternal BP + urine for protein (screening pre-eclampsia).
    • Document all findings; trigger obstetric review when growth velocity falls or Dopplers abnormal.
  • Multi-disciplinary links
    • Obstetrician (growth surveillance, timing of birth, corticosteroids).
    • Radiologist / sonographer (accurate biometry & Dopplers).
    • Dietitian or social supports if malnutrition or substance misuse.
    • Neonatology (anticipate pre-term / low-birth-weight care).
  • Aetiological categories
    • Maternal:
    • Chronic hypertension / pre-eclampsia.
    • Malnutrition, low BMI (<18.5), smoking, alcohol, drugs.
    • Diabetes with vascular disease, TORCH infections.
    • Placental:
    • Insufficiency, abnormal implantation, infarcts, abruption.
    • Fetal:
    • Chromosomal anomalies, structural malformations, multiples.
  • Pathophysiology
    • Impaired maternal blood flow ⟶ reduced O$_2$ / nutrient delivery ⟶ ↓ cellular proliferation & placental transport capacity ⟶ asymmetric growth, oligohydramnios, abnormal Dopplers.

Chronic Hypertension & Its Obstetric Relevance (context)

  • Baseline BP ≥140/90\ge 140/90 before conception or <20\ \text{weeks}.
  • Pathogenesis: vascular remodelling failure ⟶ high-resistance spiral arteries ⟶ placental hypoperfusion.
  • Direct links to both APH (abruption) & IUGR as outlined above.
  • Requires:
    • Pre-pregnancy counselling, aspirin 100–150 mg100–150\,\text{mg} nocte from ≤16\le 16 weeks.
    • Regular BP, renal function, fetal growth scans from 2828 weeks.

Shared Care & Practical Management Themes

  • Surveillance bundles: maternal vitals, fetal surveillance, lab work, ultrasound.
  • Escalation triggers: heavy bleed, sudden pain change, absent fetal movements, abnormal Doppler or CTG, uncontrolled BP.
  • Birth planning
    • Balance maturity vs risk (e.g.
    • IUGR with absent end-diastolic flow ⇒ delivery <37 wks).
    • Mode: vaginal if stable placenta & CTG; CS for major praevia, severe abruption, non-reassuring fetal status.
  • Neonatal preparation
    • Corticosteroids ×2\times 2 doses 2424 h apart if <34 wks.
    • Neonatal resus team in theatre for anticipated low weight / hypoxic neonate.
  • Post-partum considerations
    • Debrief traumatic events (massive APH, preterm CS).
    • Monitor maternal BP; adjust antihypertensives safe for lactation.
    • Arrange community follow-up, SUDI prevention education for SGA babies.
    • Long-term: cardiovascular risk counselling (placental insufficiency = marker for later disease).