Endocrinology of Pregnancy — MCQs

Endocrinology of Pregnancy Indian Medical PG Practice Questions and MCQs

Question 31: Streak gonads are seen in which of the following conditions?

A. Turner syndrome (Correct Answer)
B. Klinefelter's syndrome
C. Patau's syndrome
D. Down's syndrome

Explanation: **Explanation:** **1. Why Turner Syndrome is Correct:** Turner Syndrome (45, XO) is the most common cause of primary amenorrhea and is characterized by **gonadal dysgenesis**. In a normal fetus, two X chromosomes are required for the maintenance of primordial germ cells. In 45, XO individuals, the germ cells undergo accelerated attrition (apoptosis) during fetal life. By birth or shortly after, the ovaries are replaced by non-functional, fibrous tissue devoid of follicles, known as **"Streak Gonads."** Because these gonads cannot produce estrogen, patients present with infantile secondary sexual characteristics and elevated gonadotropins (Hypergonadotropic Hypogonadism). **2. Why the Other Options are Incorrect:** * **Klinefelter’s Syndrome (47, XXY):** This affects males. While it involves testicular dysgenesis (small, firm testes with hyalinized tubules), they are not "streak" gonads. * **Patau’s Syndrome (Trisomy 13) & Down’s Syndrome (Trisomy 21):** These are autosomal trisomies. While they involve multiple structural anomalies and intellectual disabilities, they are not typically associated with streak gonads or primary gonadal dysgenesis. **3. High-Yield Clinical Pearls for NEET-PG:** * **Karyotype:** 45, XO is the most common, but mosaicism (e.g., 45,XO/46,XX) can result in some follicular development and even pregnancy. * **Associated Features:** Short stature (most common feature), webbed neck (pterygium colli), shield chest (widely spaced nipples), and coarctation of the aorta. * **Renal Anomaly:** Horseshoe kidney is frequently associated. * **Management:** Growth Hormone (for height) and cyclic Estrogen/Progesterone (for secondary sexual characteristics and bone health). * **Note:** Streak gonads are also seen in **Swyer Syndrome** (46, XY pure gonadal dysgenesis), but there is a high risk of gonadoblastoma in those cases due to the presence of the Y chromosome.

Question 32: Nausea and vomiting are common in pregnancy. Hyperemesis gravidarum is a serious and potentially fatal problem. Which of the following findings should alert the physician to the diagnosis of hyperemesis gravidarum early in its course?

A. Electrocardiographic evidence of hypokalemia
B. Metabolic acidosis
C. Jaundice
D. Ketonuria (Correct Answer)

Explanation: ### Explanation **Hyperemesis Gravidarum (HG)** is a severe form of nausea and vomiting in pregnancy characterized by persistent vomiting, weight loss (>5% of pre-pregnancy weight), and dehydration. **1. Why Ketonuria is the Correct Answer:** The hallmark of HG is a state of **starvation metabolism**. When a patient cannot retain oral intake, the body exhausts its glycogen stores and begins breaking down fats for energy. This process produces ketone bodies (acetone, acetoacetate, and beta-hydroxybutyrate), which are excreted in the urine. **Ketonuria** is the earliest objective laboratory finding that differentiates HG from simple morning sickness and indicates the need for hospitalization and IV fluid resuscitation. **2. Analysis of Incorrect Options:** * **A. ECG evidence of hypokalemia:** While hypokalemia occurs due to loss of gastric secretions and decreased intake, ECG changes (like U-waves or T-wave flattening) are **late signs** of severe electrolyte depletion, not early diagnostic markers. * **B. Metabolic acidosis:** HG typically causes **Metabolic Alkalosis** (due to loss of hydrochloric acid from the stomach). Metabolic acidosis only occurs in terminal stages due to starvation ketosis or renal failure, making it an incorrect early finding. * **C. Jaundice:** This is a **late and grave sign** indicating hepatic involvement (centrilobular necrosis). It is not used for early diagnosis. **3. NEET-PG High-Yield Pearls:** * **Most common electrolyte abnormality:** Hypokalemic hypochloremic metabolic alkalosis. * **Hormonal link:** Strongly associated with peak levels of **hCG** and Estrogen (often seen in molar pregnancies and multiple gestations). * **Wernicke’s Encephalopathy:** A dreaded complication caused by **Vitamin B1 (Thiamine) deficiency**; always supplement Thiamine before giving Dextrose-containing fluids. * **First-line Drug:** Pyridoxine (Vit B6) +/- Doxylamine.

Question 33: Which of the following hematological parameters remains unchanged during pregnancy?

A. Blood Volume
B. Total Iron-Binding Capacity (TIBC)
C. Mean Corpuscular Hemoglobin Concentration (MCHC) (Correct Answer)
D. Serum Ferritin

Explanation: In pregnancy, the maternal body undergoes significant physiological adaptations to support the growing fetus. Understanding the distinction between absolute changes and red cell indices is crucial for NEET-PG. ### **Why MCHC is the Correct Answer** **Mean Corpuscular Hemoglobin Concentration (MCHC)** represents the concentration of hemoglobin in a given volume of packed red blood cells. While both the total hemoglobin and the Mean Corpuscular Volume (MCV) may fluctuate slightly, the **MCHC remains constant** in a healthy pregnancy. This is because the individual red blood cells maintain their hemoglobin saturation levels despite the overall expansion of blood volume. ### **Analysis of Incorrect Options** * **A. Blood Volume:** This **increases** significantly (by 40–50%). Plasma volume increases more than red cell mass, leading to "physiological anemia of pregnancy." * **B. Total Iron-Binding Capacity (TIBC):** This **increases**. As iron stores are utilized and serum iron levels fall, the liver produces more transferrin, leading to a rise in TIBC. * **D. Serum Ferritin:** This **decreases**. Ferritin is the primary storage form of iron. Due to the high demand for iron by the fetus and the expansion of maternal red cell mass, storage levels typically drop, especially in the second and third trimesters. ### **High-Yield Clinical Pearls for NEET-PG** * **MCV (Mean Corpuscular Volume):** Usually remains unchanged or may show a very slight increase. * **ESR (Erythrocyte Sedimentation Rate):** Increases significantly due to increased fibrinogen levels (making it an unreliable marker for infection in pregnancy). * **Clotting Factors:** Pregnancy is a **hypercoagulable state**. Factors VII, VIII, IX, X, and Fibrinogen increase, while Protein S levels decrease. * **Leukocytosis:** The total WBC count increases during pregnancy (up to 12,000/mm³) and can peak up to 25,000/mm³ during labor.

Question 34: What is true regarding maternal plasma osmolality during pregnancy?

A. Maternal plasma osmolality decreases early in pregnancy. (Correct Answer)
B. Maternal plasma osmolality increases throughout pregnancy.
C. Maternal plasma osmolality does not change during pregnancy.
D. Maternal plasma osmolality is affected most by increases in sodium.

Explanation: ### Explanation **1. Why Option A is Correct:** During pregnancy, there is a significant resetting of the **osmostat** (the hypothalamic threshold for thirst and ADH release). Starting as early as the 5th week of gestation, the threshold for arginine vasopressin (AVP/ADH) release and the sensation of thirst both decrease. This leads to increased water retention. Consequently, maternal plasma osmolality **decreases by approximately 10 mOsm/kg** below non-pregnant levels. This physiological hemodilution is a hallmark of normal pregnancy. **2. Why the Other Options are Incorrect:** * **Option B & C:** These are incorrect because osmolality does not increase or remain static; it undergoes a definitive decline early in the first trimester and remains low until delivery. * **Option D:** While sodium is the primary determinant of osmolality in non-pregnant states, the drop in osmolality during pregnancy is primarily driven by **water retention** exceeding the rate of sodium retention. Although total body sodium increases (by ~900 mEq), the relative expansion of plasma volume leads to a state of mild **dilutional hyponatremia** (sodium levels typically drop by 3–5 mEq/L). **3. Clinical Pearls & High-Yield Facts for NEET-PG:** * **The "10 Unit" Rule:** Remember that plasma osmolality drops by roughly **10 mOsm/kg** (from ~285 to ~275 mOsm/kg). * **Hormonal Influence:** The resetting of the osmostat is largely attributed to increased levels of **hCG** and **relaxin**. * **Plasma Volume:** Increases by 40–50%, peaking at 32–34 weeks. Since RBC mass increases only by 20–30%, this results in **physiological anemia**. * **Key Takeaway:** If a question asks about sodium levels in pregnancy, they are **decreased** (dilutional), even though total body sodium is **increased**.

Question 35: In pregnancy, at which stage does the peak level of hCG occur?

A. Early gestation (Correct Answer)
B. Mid gestation
C. Late gestation
D. Prelabour

Explanation: **Explanation:** Human Chorionic Gonadotropin (hCG) is a glycoprotein hormone produced by the syncytiotrophoblast. Its primary physiological role is to maintain the corpus luteum, ensuring the continued production of progesterone until the placenta takes over (the luteo-placental shift). **Why Early Gestation is Correct:** hCG levels become detectable in maternal serum approximately 8–9 days after fertilization. The levels rise exponentially, doubling every 48 hours. The **peak concentration** is reached between **8 to 11 weeks of gestation** (late first trimester). After this peak, levels decline significantly to a lower plateau which is maintained for the remainder of the pregnancy. **Why Other Options are Incorrect:** * **Mid Gestation:** By the second trimester (around 16–20 weeks), hCG levels have already declined to about 10–20% of their peak value as the placenta is now fully capable of steroidogenesis. * **Late Gestation/Prelabour:** hCG remains at a steady, low basal level during the third trimester. It does not show a secondary rise before labor. **High-Yield Clinical Pearls for NEET-PG:** * **Structure:** hCG shares a common **alpha (α) subunit** with LH, FSH, and TSH. The **beta (β) subunit** is unique and confers biological specificity, which is why pregnancy tests specifically measure β-hCG. * **Doubling Time:** In a healthy intrauterine pregnancy, β-hCG levels should increase by at least 66% every 48 hours. Failure to do so suggests an ectopic pregnancy or an impending miscarriage. * **Abnormal Levels:** * **Pathologically High:** Molar pregnancy (highest levels), Multiple gestations, Down Syndrome (Trisomy 21). * **Pathologically Low:** Ectopic pregnancy, Edwards Syndrome (Trisomy 18).

Question 36: What is the least likely complication in a pregnant mother with hypothyroidism?

A. Polyhydramnios (Correct Answer)
B. Recurrent abortions
C. Preterm labor
D. Hypertension

Explanation: **Explanation:** Hypothyroidism in pregnancy is characterized by a deficiency of thyroid hormones, which are essential for maintaining early pregnancy and ensuring normal fetomaternal hemodynamics. **Why Polyhydramnios is the Correct Answer:** Polyhydramnios (excess amniotic fluid) is **not** typically associated with maternal hypothyroidism. In fact, severe hypothyroidism is more likely to be associated with **Oligohydramnios** (decreased amniotic fluid), often secondary to placental insufficiency or fetal growth restriction (FGR). Polyhydramnios is more commonly linked to maternal diabetes, fetal structural anomalies (like esophageal atresia), or fetal hydrops. **Analysis of Incorrect Options:** * **Recurrent Abortions:** Thyroid hormones are crucial for the development of the corpus luteum and early placentation. Deficiency leads to an inadequate luteal phase and early pregnancy loss. * **Preterm Labor:** Hypothyroidism increases the risk of placental abruption and oxidative stress, both of which are significant triggers for spontaneous preterm birth. * **Hypertension:** There is a strong correlation between hypothyroidism and **Gestational Hypertension/Pre-eclampsia**. The lack of thyroxine leads to increased peripheral vascular resistance and altered cardiovascular reactivity. **High-Yield NEET-PG Pearls:** * **Drug of Choice:** Levothyroxine is the mainstay of treatment. * **Dose Adjustment:** Requirements increase by **30–50%** during pregnancy, starting as early as the 4th–6th week. * **Target TSH:** The goal is to keep TSH <2.5 mIU/L in the first trimester and <3.0 mIU/L in the subsequent trimesters. * **Most common cause:** Globally, iodine deficiency; in iodine-sufficient areas, **Hashimoto’s Thyroiditis**.

Question 37: Which of the following is NOT seen in Turner syndrome?

A. Mental retardation (Correct Answer)
B. 45, XO karyotype
C. Webbed neck
D. Short stature

Explanation: **Explanation:** Turner Syndrome (45, XO) is the most common sex chromosomal abnormality in females, characterized by the partial or complete loss of one X chromosome. **1. Why "Mental Retardation" is the correct answer:** In Turner syndrome, **intelligence is typically normal**. While patients may experience specific learning disabilities (such as difficulties with visuospatial processing or non-verbal memory), they do not exhibit generalized intellectual disability (mental retardation). This is a high-yield distinction compared to other chromosomal anomalies like Down Syndrome (Trisomy 21), where intellectual disability is a hallmark feature. **2. Analysis of incorrect options:** * **45, XO karyotype:** This is the classic genetic finding in Turner syndrome (seen in ~50% of cases). Other variants include mosaicism (45,X/46,XX) or structural abnormalities of the X chromosome. * **Webbed neck (Pterygium colli):** A classic phenotypic feature caused by lymphatic obstruction during fetal development (cystic hygroma). * **Short stature:** The most consistent clinical finding in Turner syndrome, primarily due to the loss of the **SHOX gene** located on the distal end of the X chromosome. **Clinical Pearls for NEET-PG:** * **Most common cause of primary amenorrhea:** Turner syndrome (due to "streak ovaries" and hypergonadotropic hypogonadism). * **Cardiac associations:** Bicuspid aortic valve (most common) and Coarctation of the aorta. * **Renal association:** Horseshoe kidney. * **Dermatological sign:** Multiple pigmented nevi and lymphedema of hands/feet at birth. * **Management:** Growth hormone therapy for height and estrogen/progesterone for secondary sexual characteristics and bone health.

Question 38: Which of the following is NOT a cause of virilization at puberty?

A. Polycystic Ovarian Disease (PCOD)
B. 5α-Reductase deficiency
C. All of the above
D. None of the above (Correct Answer)

Explanation: **Explanation:** The question asks to identify which condition is **NOT** a cause of virilization at puberty. Since both PCOD and 5α-Reductase deficiency can manifest with virilization during this period, the correct answer is **None of the above**. **1. Why the correct answer is "None of the above":** Virilization refers to the development of male secondary sexual characteristics in a female (or a phenotypically female individual). Both options A and B are established causes of virilization or masculinization that typically become apparent during the hormonal shifts of puberty. **2. Analysis of Options:** * **Polycystic Ovarian Disease (PCOD):** This is the most common cause of hyperandrogenism in adolescent girls. At puberty, the surge in LH stimulates the ovarian theca cells to produce excess androgens, leading to hirsutism, acne, and in severe cases, virilization (clitoromegaly, deepening of voice). * **5α-Reductase Deficiency:** This is a form of 46,XY Disorder of Sex Development (DSD). Affected individuals have female external genitalia at birth but undergo significant "masculinization" at puberty. The massive increase in testosterone (which does not require conversion to DHT for all its effects) causes the voice to deepen, muscle mass to increase, and the clitoris-like phallus to enlarge (the "penis-at-twelve" phenomenon). **Clinical Pearls for NEET-PG:** * **PCOD Hallmark:** High LH:FSH ratio (>2:1) and hyperinsulinemia. * **5α-Reductase Deficiency:** Characterized by normal testosterone levels but low Dihydrotestosterone (DHT). It is often classically described in the "Guevedoces" population of the Dominican Republic. * **Differential Diagnosis:** Always rule out **Late-onset (Non-classic) Congenital Adrenal Hyperplasia (CAH)** and **Androgen-secreting tumors** (Sertoli-Leydig cell tumors) when a patient presents with rapid-onset virilization at puberty.

Question 39: What is the 1-hour post-glucose load plasma glucose level that is diagnostic for gestational diabetes mellitus?

A. 140 mg%
B. 150 mg%
C. 180 mg% (Correct Answer)
D. 200 mg%

Explanation: **Explanation:** The diagnosis of Gestational Diabetes Mellitus (GDM) is primarily based on the **Carpenter-Coustan criteria** or the **NDDG criteria** following a 100g 3-hour Oral Glucose Tolerance Test (OGTT), or the **IADPSG/WHO 2013 criteria** using a 75g 2-hour OGTT. Under the **IADPSG (International Association of Diabetes and Pregnancy Study Groups)** and **WHO 2013** guidelines, GDM is diagnosed if one or more of the following plasma glucose values are met or exceeded after a 75g glucose load: * **Fasting:** 92 mg/dL * **1-hour:** **180 mg/dL** (Correct Answer) * **2-hour:** 153 mg/dL **Analysis of Options:** * **A (140 mg%):** This is the traditional "screening" threshold for the 50g Glucose Challenge Test (GCT). If a patient exceeds this, they proceed to a diagnostic OGTT. * **B (150 mg%):** This value does not correspond to any standard diagnostic threshold for GDM. * **D (200 mg%):** A random plasma glucose of ≥200 mg/dL (with symptoms) or a 2-hour post-load value of ≥200 mg/dL is diagnostic of **Overt (Pre-gestational) Diabetes**, not specifically GDM. **High-Yield Clinical Pearls for NEET-PG:** * **DIPSI Guidelines (Indian Context):** A single-step 75g glucose load is given regardless of the last meal. A 2-hour value **≥140 mg/dL** is diagnostic of GDM. * **Screening Timing:** Ideally performed at **24–28 weeks** of gestation. * **First Visit:** High-risk patients should be screened at the first prenatal visit to rule out pre-existing Type 2 Diabetes. * **Drug of Choice:** **Insulin** remains the gold standard, though Metformin is increasingly used in clinical practice.

Question 40: A 15-year-old girl complains of failure to attain menarche. Her height is 4 feet. She has not yet developed secondary sexual characteristics. Ultrasound shows a uterus and vagina. FSH and LH levels are high. What is the best step in confirming the diagnosis?

A. Perform a CT scan
B. Perform a Karyotype (Correct Answer)
C. Perform a buccal smear
D. Perform a progesterone withdrawal test

Explanation: ### Explanation This clinical scenario describes a case of **Primary Amenorrhea** with **Hypergonadotropic Hypogonadism** (High FSH/LH). **1. Why Karyotyping is the Correct Answer:** The patient presents with the classic triad of **Turner Syndrome (45,XO)**: * **Short Stature:** (Height 4 feet). * **Sexual Infantilism:** Failure of secondary sexual characteristics due to streak ovaries (gonadal dysgenesis). * **Hypergonadotropic Hypogonadism:** Low estrogen levels (due to ovarian failure) result in a lack of negative feedback, causing the pituitary to secrete high levels of FSH and LH. In any patient with primary amenorrhea, short stature, and high gonadotropins, **Karyotyping** is the gold standard and essential next step to confirm the chromosomal abnormality and rule out mosaics. **2. Why Other Options are Incorrect:** * **CT Scan:** Not indicated. While it could visualize pelvic structures, Ultrasound has already confirmed the presence of a uterus and vagina. It does not provide a genetic diagnosis. * **Buccal Smear:** This looks for Barr bodies. While it was used historically, it is unreliable for diagnosing Turner syndrome (especially mosaicism) and has been replaced by formal karyotyping. * **Progesterone Withdrawal Test:** This tests for endogenous estrogen and outflow tract patency. In this patient, estrogen is already known to be low (lack of secondary sexual characteristics), so the test would be negative and provide no new diagnostic information. ### Clinical Pearls for NEET-PG: * **Most common cause of Primary Amenorrhea:** Turner Syndrome (45,XO). * **Most common cause of Delayed Puberty with High FSH:** Turner Syndrome. * **Mullerian Structures:** In Turner Syndrome, the uterus and vagina are **present** because there is no Anti-Mullerian Hormone (AMH) produced (no testes). * **High-Yield Association:** Always screen Turner patients for **Coarctation of the Aorta** and **Bicuspid Aortic Valve**.

Practice by Chapter

Endocrine Changes in Normal Pregnancy

Practice Questions

Thyroid Disorders in Pregnancy

Practice Questions

Diabetes in Pregnancy

Practice Questions

Adrenal Disorders in Pregnancy

Practice Questions

Pituitary Disorders in Pregnancy

Practice Questions

Hyperemesis Gravidarum

Practice Questions

Hormonal Regulation of Labor

Practice Questions

Pharmacokinetics of Hormones in Pregnancy

Practice Questions

Fetal Endocrine Development

Practice Questions

Placental Hormones

Practice Questions

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