📘 Placenta

(Important for Obstetrics, Anatomy & Physiology, Community Health Nursing, NHM, AIIMS, GPSC Staff Nurse Exams)

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✅ 1. Introduction / Definition:

The placenta is a temporary, disc-shaped organ that forms during pregnancy, connecting the mother and fetus.
It facilitates the exchange of nutrients, gases, and waste products, while also serving endocrine, immunologic, and metabolic functions.

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✅ 2. Formation and Development:

• Begins developing from trophoblast cells during the second week of pregnancy.
• Fully formed by the end of the first trimester (~12 weeks).
• Originates from:
  • Fetal side: Chorion frondosum
  • Maternal side: Decidua basalis

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✅ 3. Structure of Placenta:

• Shape: Discoid
• Weight: ~500–600 grams
• Diameter: ~15–20 cm
• Thickness: ~2–3 cm
• Surfaces:
  • Fetal surface: Smooth, shiny, covered by amnion; has umbilical cord
  • Maternal surface: Rough, red, divided into 15–20 cotyledons

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✅ 4. Circulation:

• Fetal blood flows through umbilical arteries (2) and umbilical vein (1)
• Maternal blood flows through spiral arteries in the uterine wall
• No direct mixing of maternal and fetal blood (separated by placental barrier)

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✅ 5. Functions of the Placenta:

🔹 A. Respiratory Function:

• Transfers oxygen to fetus and removes carbon dioxide

🔹 B. Nutrition:

• Transfers glucose, amino acids, fatty acids, vitamins, minerals from mother to fetus

🔹 C. Excretory:

• Removes wastes like urea, creatinine from fetal blood

🔹 D. Endocrine:

Produces important pregnancy hormones:

• hCG – Maintains corpus luteum
• hPL – Promotes fetal growth & maternal glucose availability
• Estrogen – Uterine growth, blood flow
• Progesterone – Maintains endometrium and prevents contractions

🔹 E. Immune Function:

• Transfers maternal antibodies (IgG) for fetal passive immunity

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✅ 6. Placental Barrier:

• Separates maternal and fetal circulation
• Components: Syncytiotrophoblast, cytotrophoblast, fetal connective tissue, endothelium
• Becomes thinner as pregnancy advances

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✅ 7. Separation of Placenta:

• Occurs during third stage of labor
• Signs of separation: Gush of blood, uterus becomes firm, cord lengthens
• Expelled within 5–30 minutes after birth
• Retained placenta if not expelled within 30 minutes

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✅ 8. Nursing Responsibilities:

• Monitor for complete expulsion of placenta
• Inspect placenta:
  • Intact membranes
  • 2 arteries + 1 vein
  • Cotyledons complete
• Monitor mother for hemorrhage, uterine tone
• Document placenta delivery time and condition

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✅ 9. Golden One-Liners for Quick Revision:

• Placenta = Lifeline between mother and fetus
• Fetal part: Chorion frondosum, Maternal part: Decidua basalis
• hCG maintains pregnancy in early weeks
• 15–20 cotyledons on maternal surface
• Placenta fully formed by 12 weeks
• Umbilical cord: 2 arteries + 1 vein

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✅ 10. MCQs for Practice:

Q1. The placenta is fully developed by which gestational week?
a) 6 weeks
b) 8 weeks
c) 12 weeks
d) 16 weeks
Correct Answer: c) 12 weeks

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Q2. The fetal part of the placenta is derived from:
a) Decidua basalis
b) Amnion
c) Chorion frondosum
d) Myometrium
Correct Answer: c) Chorion frondosum

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Q3. Which hormone is secreted by the placenta?
a) FSH
b) Estrogen
c) TSH
d) ADH
Correct Answer: b) Estrogen

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Q4. Which of the following is not a function of placenta?
a) Hormone production
b) Gas exchange
c) Digestion
d) Immune transfer
Correct Answer: c) Digestion

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Q5. The normal number of placental cotyledons is:
a) 10
b) 15–20
c) 25–30
d) 5
Correct Answer: b) 15–20

📘 Abnormalities of Placenta

(Important for Obstetric Nursing, Anatomy & Physiology, NHM, AIIMS, GPSC Staff Nurse Exams)

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✅ 1. Introduction / Definition:

Abnormalities of placenta refer to structural, positional, or functional deviations from the normal placenta.
These abnormalities can affect fetal growth, labor, and maternal health and may be detected antenatally by ultrasound or clinically during labor or postpartum.

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✅ 2. Classification:

Abnormalities can be categorized into:

1. Positional abnormalities
2. Structural/morphological abnormalities
3. Invasive/morbid adherence disorders
4. Functional abnormalities

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✅ 3. Positional Abnormalities:

🔹 1. Placenta Previa:

• Placenta implanted in the lower uterine segment, partially or completely covering the internal os.
• Types:
  • Type I: Low-lying
  • Type II: Marginal
  • Type III: Partial
  • Type IV: Complete
• Symptoms: Painless vaginal bleeding in 3rd trimester
• Management: Hospitalization, bed rest, cesarean section if complete previa

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🔹 2. Placental Abruption (Abruptio Placentae):

• Premature separation of a normally implanted placenta from uterine wall
• Types:
  • Concealed
  • Revealed
  • Mixed
• Symptoms: Painful bleeding, uterine tenderness, fetal distress
• Management: Emergency delivery, fluid resuscitation

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✅ 4. Structural / Morphological Abnormalities:

Type	Description	Risk
Succenturiate placenta	Presence of accessory lobe	Retained lobe → PPH, infection
Circumvallate placenta	Thickened ring around fetal side due to folded membranes	IUGR, preterm labor
Battledore placenta	Marginal cord insertion	Usually benign, may cause FHR deceleration
Velamentous insertion	Cord inserts into membranes, not placenta → vessels unprotected	Vasa previa, fetal bleeding risk
Furcate insertion	Vessels divide before reaching placenta	Risk of rupture and fetal hemorrhage
Placental cysts	Fluid-filled sacs on placenta	Often benign; large ones may affect circulation

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✅ 5. Morbid Adherent Placenta (Placenta Accreta Spectrum):

Type	Description
Placenta accreta	Villi attach to myometrium (superficial)
Placenta increta	Villi invade into myometrium
Placenta percreta	Villi penetrate through uterine wall, may invade bladder

• Risk factors: Previous cesarean section, placenta previa, uterine surgery
• Complications: Severe PPH, retained placenta, need for hysterectomy
• Management: Planned cesarean hysterectomy, blood transfusion

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✅ 6. Functional Abnormalities:

Condition	Effect
Placental insufficiency	Inadequate transfer of oxygen/nutrients → IUGR, oligohydramnios
Chorioangioma	Benign placental tumor → may cause polyhydramnios or hydrops
Calcification (Aging placenta)	Common after 37 weeks → usually physiological, may need monitoring if early

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✅ 7. Clinical Signs & Diagnosis:

• Ultrasound: First-line tool for placenta position and structure
• Color Doppler: Assesses cord insertion and blood flow
• MRI: In suspected placenta accreta spectrum
• Antenatal symptoms: Bleeding, fetal growth restriction, abnormal FHR
• Postnatal clues: Retained placenta, PPH

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✅ 8. Complications:

• Maternal:
  • Hemorrhage (antepartum/postpartum)
  • Shock, sepsis, hysterectomy
• Fetal:
  • IUGR
  • Fetal distress
  • Preterm birth
  • IUFD (intrauterine fetal death)

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✅ 9. Nursing Responsibilities:

• Monitor bleeding and uterine tone during labor
• Prepare for emergency delivery in abruption/previa
• Post-delivery inspection of placenta for missing lobes
• Maintain IV access, arrange blood transfusion if needed
• Counsel mother on high-risk future pregnancies

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✅ 10. Golden One-Liners for Quick Revision:

• Placenta previa = Painless 3rd trimester bleeding
• Abruptio placentae = Painful vaginal bleeding with tender uterus
• Succenturiate placenta → Accessory lobe → Risk of retained placenta
• Velamentous insertion → Risk of vasa previa and fetal hemorrhage
• Placenta accreta spectrum = Risk of massive PPH
• Circumvallate placenta → Associated with IUGR, preterm labor

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✅ 11. MCQs for Practice:

Q1. Placenta previa typically presents with:
a) Painful bleeding
b) No bleeding
c) Painless vaginal bleeding
d) Fever and chills
Correct Answer: c) Painless vaginal bleeding

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Q2. Velamentous cord insertion increases risk of:
a) Anemia
b) Cord prolapse
c) Vasa previa
d) Neural tube defects
Correct Answer: c) Vasa previa

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Q3. In placenta accreta, the villi:
a) Attach to endometrium
b) Invade bladder
c) Invade myometrium
d) Remain in amnion
Correct Answer: c) Invade myometrium

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Q4. Which placental anomaly includes an accessory lobe?
a) Circumvallate placenta
b) Succenturiate placenta
c) Battledore placenta
d) Percreta
Correct Answer: b) Succenturiate placenta

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Q5. Placenta percreta is dangerous because:
a) It causes premature labor
b) It fails to attach
c) It invades through the uterine wall
d) It causes neural defects
Correct Answer: c) It invades through the uterine wall