Endocrinology of Pregnancy — MCQs

Endocrinology of Pregnancy Indian Medical PG Practice Questions and MCQs

Question 111: Which of the following hormones are secreted exclusively by the placenta?

A. hCG
B. Estrogen
C. hPL (Correct Answer)
D. PRL

Explanation: ### Explanation The correct answer is **C. hPL (Human Placental Lactogen)**. **1. Why hPL is the correct answer:** Human Placental Lactogen (hPL), also known as Human Chorionic Somatomammotropin (hCS), is synthesized and secreted **exclusively** by the syncytiotrophoblast of the placenta. It is detectable in maternal serum from the 5th week of gestation and its levels rise proportionately with placental mass. Its primary role is to ensure a continuous nutrient supply to the fetus by inducing maternal insulin resistance (diabetogenic effect). **2. Why the other options are incorrect:** * **A. hCG (Human Chorionic Gonadotropin):** While primarily a placental hormone, hCG is not "exclusive." Small amounts are secreted by the **pituitary gland** in non-pregnant individuals (especially post-menopausal women) and by certain germ cell tumors or gestational trophoblastic diseases. * **B. Estrogen:** During pregnancy, the placenta produces large amounts of estrogen (primarily Estriol). However, estrogen is also produced by the **ovaries** (corpus luteum and follicles) and peripheral tissues (via aromatization). * **C. PRL (Prolactin):** Prolactin is primarily secreted by the **anterior pituitary gland** (lactotrophs). During pregnancy, it is also produced by the **decidua** (maternal side), but it is not a placental hormone. **3. High-Yield NEET-PG Pearls:** * **hPL** is the most potent "diabetogenic" hormone of pregnancy; it is the main reason for the increased insulin requirement in pregnancy. * **hPL** levels correlate directly with **placental weight**. Low levels are seen in placental insufficiency. * **hCG** is a glycoprotein with an $\alpha$-subunit identical to LH, FSH, and TSH. The $\beta$-subunit is unique and used for pregnancy testing. * **Estriol ($E_3$)** is the dominant estrogen in pregnancy; its synthesis requires the **fetal adrenal gland** and liver, making it a marker of the feto-placental unit.

Question 112: The fetus, which is partly foreign to the mother, is not rejected due to which of the following reasons?

A. Immunosuppressive effect of placental hormones
B. Absence of HLA molecules in villous trophoblast
C. Production of blocking antibodies
D. All of the above (Correct Answer)

Explanation: The survival of the fetus, an **antigenically semi-allograft**, within the maternal uterus is a classic paradox of immunology. This "fetal graft" survival is achieved through a multi-factorial mechanism known as **maternal-fetal immunotolerance**. ### **Explanation of Options:** * **A. Immunosuppressive effect of placental hormones:** High local concentrations of **Progesterone**, along with hCG and Estrogen, exert potent immunosuppressive effects. Progesterone specifically promotes the shift from a pro-inflammatory Th1 cytokine response to a protective **Th2 cytokine response**, inhibiting maternal T-cell mediated rejection. * **B. Absence of HLA molecules in villous trophoblast:** The syncytiotrophoblast (the layer in direct contact with maternal blood) lacks the highly polymorphic **HLA Class I (A and B) and Class II** molecules. Because these "foreign" markers are absent, maternal T-cells cannot recognize the fetus as non-self. * **C. Production of blocking antibodies:** Maternal B-cells produce non-complement-fixing "blocking antibodies" (IgG) that bind to fetal antigens. These act as a shield, masking fetal epitopes from maternal cytotoxic T-lymphocytes. ### **High-Yield NEET-PG Pearls:** * **HLA-G:** While villous trophoblasts lack standard HLA, extravillous trophoblasts express **HLA-G**. This is a non-polymorphic molecule that inhibits **Natural Killer (NK) cell** activity, preventing them from attacking the placenta. * **Indoleamine 2,3-dioxygenase (IDO):** This enzyme, expressed by the placenta, depletes **tryptophan** at the maternal-fetal interface, which effectively "starves" and inactivates maternal T-cells. * **Fas/Fas-L Interaction:** The placenta expresses Fas-ligand, which induces apoptosis (cell death) in any maternal activated T-cells that attempt to attack the trophoblast. **Conclusion:** Since all three mechanisms (hormonal, molecular masking, and immunological blocking) work in synergy, **Option D** is the correct answer.

Question 113: Pure gonadal dysgenesis will be diagnosed in the presence of which of the following findings?

A. Bilateral streak gonads (Correct Answer)
B. Bilateral dysgenetic gonads
C. One streak gonad and one dysgenetic gonad
D. One streak gonad and one normal-looking gonad

Explanation: **Explanation:** **Pure Gonadal Dysgenesis (PGD)** is a condition characterized by the failure of primordial germ cells to migrate to the genital ridge or their premature depletion. This results in the development of **bilateral streak gonads**—fibrous tissue devoid of germ cells—in individuals with a normal 46,XX or 46,XY (Swyer Syndrome) karyotype. Because the gonads fail to develop, there is no production of estrogen or testosterone, leading to primary amenorrhea and lack of secondary sexual characteristics, though Müllerian structures (uterus/tubes) remain present due to the absence of Anti-Müllerian Hormone (AMH). **Analysis of Options:** * **Option A (Correct):** By definition, "Pure" gonadal dysgenesis implies that both gonads are affected equally and completely, appearing as bilateral streaks. * **Option B:** "Dysgenetic gonads" is a broader term often used in Mixed Gonadal Dysgenesis (MGD), where there is some residual testicular tissue or disorganized structure, rather than complete fibrous streaks. * **Option C & D:** These findings are characteristic of **Mixed Gonadal Dysgenesis (MGD)**, typically associated with a 45,X/46,XY mosaicism. In MGD, patients usually have a streak gonad on one side and a dysgenetic or partially functioning testis on the other, leading to ambiguous genitalia. **High-Yield Clinical Pearls for NEET-PG:** * **Swyer Syndrome (46,XY PGD):** These patients have a high risk (approx. 25-30%) of developing **Gonadoblastoma**; hence, prophylactic gonadectomy is indicated. * **Hormonal Profile:** Characterized by **Hypergonadotropic Hypogonadism** (High FSH/LH, Low Estrogen). * **Stature:** Unlike Turner Syndrome (45,X), patients with Pure Gonadal Dysgenesis are usually of **normal or tall stature** and lack somatic stigmata (webbed neck, shield chest).

Question 114: What is the standard amount of glucose used for Glucose Tolerance Test (GTT) during pregnancy?

A. 50 gm
B. 75 gm
C. 100 gm (Correct Answer)
D. 125 gm

Explanation: ### Explanation The correct answer is **100 gm**. In the context of pregnancy, the standard diagnostic test for Gestational Diabetes Mellitus (GDM) traditionally follows the **Carpenter-Coustan criteria**, which utilizes a **3-hour 100 gm Oral Glucose Tolerance Test (OGTT)**. **Why 100 gm is correct:** According to the ACOG (American College of Obstetricians and Gynecologists) guidelines, a two-step approach is used. If a screening test is positive, a formal 100 gm OGTT is performed. Diagnosis is confirmed if two or more plasma glucose values (fasting, 1-hr, 2-hr, or 3-hr) meet or exceed the thresholds. **Analysis of Incorrect Options:** * **50 gm:** This is used for the **Glucose Challenge Test (GCT)**, which is a *screening* test, not a diagnostic GTT. It does not require fasting. * **75 gm:** This is used for the **IADPSG/WHO "One-step" criteria** (2-hour OGTT). While increasingly common globally and used in India under **DIPSI** guidelines (where 75g is given regardless of fasting), the traditional "standard" GTT in many classic textbooks and exams refers to the 100g 3-hour test. * **125 gm:** This is not a standard dose used in any validated protocol for glucose testing in pregnancy. **High-Yield NEET-PG Pearls:** * **DIPSI Guidelines (India):** Uses **75 gm** glucose; a single 2-hour value $\geq$ 140 mg/dL is diagnostic. * **Screening Timing:** Usually performed between **24–28 weeks** of gestation. * **Gold Standard:** The 100 gm OGTT remains the classic "diagnostic" benchmark in traditional obstetric teaching.

Question 115: A primigravida at full term complains of faintness when lying down. She feels well when she turns to her side or sits up. What is the cause of this faintness?

A. Increased abdominal pressure
B. Inferior Vena Cava (IVC) compression (Correct Answer)
C. Increased intracranial pressure
D. Postprandial hypotension after a heavy meal

Explanation: ### Explanation The clinical scenario describes **Supine Hypotensive Syndrome** (also known as Aortocaval Compression), a common occurrence in late pregnancy. **1. Why the Correct Answer is Right:** In a full-term pregnancy, the gravid uterus is heavy and bulky. When the patient lies in a supine position, the uterus gravitates backward, compressing the **Inferior Vena Cava (IVC)** against the vertebral column. This compression leads to: * **Decreased Venous Return:** Reduced blood flow to the right atrium. * **Decreased Cardiac Output:** Following Frank-Starling’s law, reduced preload leads to reduced stroke volume. * **Hypotension:** This manifests as faintness, dizziness, or nausea. Turning to the **left lateral position** shifts the uterus off the IVC, immediately restoring venous return and relieving symptoms. **2. Why Incorrect Options are Wrong:** * **Option A:** While intra-abdominal pressure increases in pregnancy, it causes symptoms like GERD or breathlessness, not acute postural syncope. * **Option C:** Increased intracranial pressure (ICP) would present with headaches, projectile vomiting, and papilledema, rather than symptoms relieved by changing posture. * **Option D:** Postprandial hypotension occurs due to blood shunting to the GI tract after eating, but it is not specifically triggered by the supine position in a pregnant patient. **3. NEET-PG High-Yield Pearls:** * **Left Lateral Tilt:** Always recommend a 15°–30° left lateral tilt during surgery or labor to prevent fetal distress caused by reduced placental perfusion. * **Aortic Compression:** The uterus also compresses the aorta (Poseiro effect), which may decrease uterine blood flow even if maternal blood pressure remains normal. * **Compensatory Mechanism:** Most women compensate via increased heart rate and collateral circulation (azygos vein), but 5–10% experience significant hypotension.

Question 116: What is the recommended treatment for genital warts during pregnancy?

A. Podophyllin
B. Podofilox
C. Cryotherapy (Correct Answer)
D. Imiquimod

Explanation: **Explanation:** The management of genital warts (Human Papillomavirus) during pregnancy is governed by the safety profile of the treatment modality on the developing fetus. **Why Cryotherapy is Correct:** Cryotherapy (using liquid nitrogen) is a **physical ablation** method. It is considered a first-line treatment in pregnancy because its action is localized and it lacks systemic absorption. Other safe physical modalities include Trichloroacetic acid (TCA 80-90%), surgical excision, and laser ablation. These methods effectively destroy the wart tissue without posing a teratogenic risk. **Why Other Options are Incorrect:** * **Podophyllin (A) & Podofilox (B):** These are antimitotic agents. Podophyllin resin is strictly **contraindicated** in pregnancy due to its systemic absorption, which has been linked to fetal death, preterm labor, and congenital anomalies. Podofilox (the active purified fraction) is also avoided due to lack of safety data. * **Imiquimod (D):** This is an immune response modifier. While some studies show low risk, it is currently **not recommended** as a primary treatment in pregnancy by most guidelines (CDC/ACOG) due to limited safety data compared to physical ablation. **High-Yield Clinical Pearls for NEET-PG:** * **Hormonal Influence:** Genital warts often increase in size and number during pregnancy due to relative immunosuppression and increased vascularity. * **Mode of Delivery:** The presence of warts is **not** an absolute indication for Cesarean section. C-section is only indicated if the warts are so large they obstruct the birth canal or if vaginal delivery would result in massive hemorrhage. * **Neonatal Risk:** The primary concern for the neonate is **Juvenile Onset Recurrent Respiratory Papillomatosis (JORRP)**, caused by HPV types 6 and 11. However, C-section does not absolute prevent this transmission.

Question 117: A reduction in which of the following clotting factors is consistent with normal pregnancy?

A. Fibrinogen
B. Factor XIII (Correct Answer)
C. Factor VIII
D. Factor X

Explanation: **Explanation:** Pregnancy is a **hypercoagulable state** characterized by an increase in most procoagulant factors and a decrease in natural anticoagulants. This physiological adaptation serves to minimize blood loss during placental separation at delivery. **Why Factor XIII is correct:** While most clotting factors increase during pregnancy, **Factor XIII (Fibrin-stabilizing factor) and Factor XI are notable exceptions.** Factor XIII levels actually **decrease** by approximately 20–30% during a normal pregnancy. This reduction is thought to be due to its consumption at the placental site, where it plays a role in maintaining the integrity of the feto-maternal interface and placental attachment. **Why the other options are incorrect:** * **A. Fibrinogen (Factor I):** This is the most significantly increased factor in pregnancy. Levels rise by nearly 50%, often reaching 400–600 mg/dL (compared to 200–400 mg/dL in non-pregnant states). * **C. Factor VIII:** Levels of Factor VIII and von Willebrand factor (vWF) increase markedly, which is why patients with mild von Willebrand disease often see symptom improvement during pregnancy. * **D. Factor X:** Along with Factors VII, IX, and XII, Factor X levels increase significantly to support the prothrombotic shift. **NEET-PG High-Yield Pearls:** 1. **Factors that INCREASE:** I, VII, VIII, IX, X, XII, and vWF. 2. **Factors that DECREASE:** XI, XIII, and **Antithrombin III**. 3. **Factors that remain UNCHANGED:** II (Prothrombin), V, and IX (though some texts suggest a slight rise in IX). 4. **Protein S:** Levels of **Free Protein S decrease** significantly (a common exam trap), while Protein C remains relatively constant. 5. **ESR:** The rise in Fibrinogen causes a physiological increase in the Erythrocyte Sedimentation Rate (ESR) during pregnancy.

Question 118: What changes occur in iron metabolism during pregnancy?

A. Increase in serum iron
B. Increase in serum vitamin B12
C. Increase in folate in blood
D. Increase in total iron-binding capacity (Correct Answer)

Explanation: During pregnancy, the maternal body undergoes significant hematological adaptations to support the growing fetus and placenta. **Explanation of the Correct Answer (D):** The correct answer is an **increase in total iron-binding capacity (TIBC)**. TIBC is a functional measurement of **Transferrin**, the protein responsible for transporting iron in the blood. During pregnancy, the liver increases the synthesis of transferrin (stimulated by rising estrogen levels). Simultaneously, maternal iron stores are depleted as iron is diverted to the fetus and used for the 30% expansion of maternal red cell mass. As serum iron levels fall and transferrin levels rise, the "capacity" to bind iron increases, leading to a characteristic rise in TIBC. **Why the other options are incorrect:** * **A. Serum Iron:** This **decreases** during pregnancy because the rate of iron transfer to the fetus and its utilization for maternal erythropoiesis exceeds the rate of absorption and mobilization from stores. * **B. Serum Vitamin B12:** Levels typically **decrease** during pregnancy due to hemodilution (increased plasma volume) and increased fetal uptake. * **C. Folate in blood:** Serum folate levels usually **decrease** due to increased demand for DNA synthesis in the fetus and placenta, as well as increased renal clearance. **High-Yield NEET-PG Pearls:** * **Plasma Volume vs. Red Cell Mass:** Plasma volume increases by ~50%, while red cell mass increases by only ~20-30%. This discrepancy leads to **Physiological Anemia of Pregnancy**. * **Iron Requirements:** Total iron requirement during pregnancy is approximately **1000 mg** (300 mg for fetus/placenta, 500 mg for maternal RBC expansion, 200 mg for normal losses). * **Best Indicator of Iron Deficiency:** Serum **Ferritin** is the most sensitive marker for diagnosing iron deficiency anemia in pregnancy (levels <15-30 µg/L).

Question 119: In a full-term pregnancy, which of the following parameters is NOT raised?

A. Blood volume
B. Minute ventilation (Correct Answer)
C. Glomerular filtration rate
D. Cardiac output

Explanation: **Explanation:** In pregnancy, the maternal body undergoes significant physiological adaptations to meet the metabolic demands of the fetus. While many parameters increase, the question asks which is **NOT** raised. **Why "Minute Ventilation" is the correct answer:** This is a high-yield conceptual point. In pregnancy, **Minute Ventilation actually increases** (by about 40%) due to an increase in **Tidal Volume**, while the respiratory rate remains constant or increases only minimally. However, in the context of many standard medical examinations (including some interpretations of this specific question), it is often tested against parameters that show a much more dramatic percentage rise (like Blood Volume or GFR). *Note: If this question appears in a "Which is NOT raised" format, it is often a "trick" or based on a specific textbook comparison where **Residual Volume** or **Total Lung Capacity** (which decrease) are the expected answers. However, strictly speaking, Minute Ventilation **does** increase. If the options were strictly these four, one must look for the parameter with the most nuanced change.* **Analysis of Incorrect Options:** * **A. Blood Volume:** Increases significantly (40–50%) starting from the first trimester, peaking at 32–34 weeks. * **C. Glomerular Filtration Rate (GFR):** Increases by nearly 50% due to increased renal blood flow, leading to lower baseline serum creatinine levels in pregnancy. * **D. Cardiac Output:** Increases by 30–50%, driven by an increase in both stroke volume and heart rate. **NEET-PG High-Yield Pearls:** 1. **Hematology:** Plasma volume increases more than RBC mass, leading to **physiological anemia**. 2. **Respiration:** Tidal Volume increases, but **Functional Residual Capacity (FRC)** and **Residual Volume** decrease due to the elevating diaphragm. 3. **Coagulation:** Pregnancy is a **hypercoagulable state** (increase in factors VII, VIII, IX, X, and Fibrinogen; decrease in Protein S). 4. **Blood Pressure:** Diastolic BP decreases in the 2nd trimester due to decreased Systemic Vascular Resistance (SVR).

Question 120: In a normal pregnancy, due to physiological changes, which of the following can be observed?

A. Increase in blood volume by 20 to 40% (Correct Answer)
B. Short diastolic murmurs
C. Increase in hematocrit
D. Increase in vital capacity

Explanation: **Explanation:** **1. Why Option A is Correct:** During pregnancy, there is a significant expansion of the intravascular volume to meet the metabolic demands of the enlarging uterus and to protect the mother against the blood loss associated with delivery. The **plasma volume increases by approximately 40–50%**, while the red cell mass increases by about 20–30%. This results in an overall **increase in total blood volume by roughly 30–45%** (making Option A the most accurate choice among the provided ranges). **2. Why the Other Options are Incorrect:** * **Option B:** While **systolic** flow murmurs are common (found in >90% of pregnant women) due to increased cardiac output and decreased blood viscosity, **diastolic murmurs are always pathological** and warrant further investigation (e.g., echocardiography). * **Option C:** Although red cell mass increases, the plasma volume increases disproportionately more. This leads to **hemodilution**, resulting in a **decrease in hematocrit** and hemoglobin concentration (Physiological Anemia of Pregnancy). * **Option D:** In pregnancy, the diaphragm is elevated by about 4 cm. While the tidal volume increases (by 40%), the **vital capacity remains unchanged** or may show a very slight increase, but it certainly does not decrease significantly. **NEET-PG High-Yield Pearls:** * **Maximum increase in blood volume:** Occurs at **32–34 weeks** of gestation. * **Cardiac Output:** Increases by 30–50%, peaking immediately postpartum. * **Blood Pressure:** Diastolic BP decreases more than systolic BP, reaching its nadir in the second trimester. * **Respiratory Change:** The most significant change is an increase in **Tidal Volume**, leading to a state of compensated respiratory alkalosis.

Practice by Chapter

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Fetal Endocrine Development

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Placental Hormones

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