Endocrinology of Pregnancy — MCQs

Endocrinology of Pregnancy Indian Medical PG Practice Questions and MCQs

Question 181: At what intrauterine gestational age are peak hCG levels typically observed?

A. 8-10 weeks (Correct Answer)
B. 11-13 weeks
C. 20 weeks
D. 25 weeks

Explanation: **Explanation:** Human Chorionic Gonadotropin (hCG) is a glycoprotein hormone secreted by the **syncytiotrophoblast**. Its primary physiological role is to maintain the corpus luteum, ensuring the continued production of progesterone until the "luteal-placental shift" occurs. **1. Why 8-10 weeks is correct:** hCG levels rise exponentially following implantation. They typically double every 48 hours in early pregnancy, reaching their **peak concentration between 8 and 10 weeks** of gestation (approximately 60–70 days after the Last Menstrual Period). At this peak, levels can reach up to 100,000 mIU/mL. After 10 weeks, the levels begin to decline, reaching a stable plateau (nadir) around 20 weeks. **2. Analysis of Incorrect Options:** * **11-13 weeks:** By this time, hCG levels have already begun their physiological decline as the placenta takes over progesterone production. * **20 weeks:** This is the period of the **"nadir"** (the lowest stable level maintained for the remainder of the pregnancy), which is roughly 10-20% of the peak concentration. * **25 weeks:** hCG remains at a constant, lower plateau during the second and third trimesters; it does not peak during this period. **High-Yield Clinical Pearls for NEET-PG:** * **Structure:** hCG is a heterodimer. The **alpha (α) subunit** is identical to LH, FSH, and TSH. The **beta (β) subunit** is unique, which is why pregnancy tests specifically measure **beta-hCG**. * **Doubling Time:** In a healthy intrauterine pregnancy, β-hCG levels should increase by at least 66% (or roughly double) every 48 hours. Failure to do so suggests an ectopic pregnancy or a non-viable intrauterine pregnancy. * **Abnormal Peaks:** Pathologically high hCG levels (>100,000 mIU/mL) are associated with **Molar Pregnancy** (Hydatidiform mole) and Multiple Gestations. * **Down Syndrome Screening:** In the second-trimester Quadruple marker test, **elevated hCG** (along with Inhibin-A) is a marker for Trisomy 21.

Question 182: Which is the least likely physiological change in pregnancy?

A. Increase in intravascular volume
B. Increase in cardiac output
C. Increase in stroke volume
D. Increase in peripheral vascular resistance (Correct Answer)

Explanation: **Explanation:** In pregnancy, the cardiovascular system undergoes significant adaptation to meet the metabolic demands of the fetus. The correct answer is **D (Increase in peripheral vascular resistance)** because systemic vascular resistance (SVR) actually **decreases** significantly during pregnancy. **Why D is correct:** The decrease in SVR is one of the earliest physiological changes, driven by high levels of **progesterone** (a smooth muscle relaxant) and increased production of local vasodilators like **nitric oxide and prostaglandins**. This drop in resistance is necessary to accommodate the massive increase in blood volume and ensures adequate perfusion to the uteroplacental unit. **Why other options are incorrect:** * **A. Increase in intravascular volume:** Plasma volume increases by 40–50%, starting as early as 6 weeks. This is a hallmark of normal pregnancy. * **B. Increase in cardiac output:** Cardiac output increases by 30–50%. It is the product of Heart Rate × Stroke Volume, both of which increase during pregnancy. * **C. Increase in stroke volume:** Stroke volume increases early in pregnancy (peaking at 20–24 weeks) due to increased blood volume and decreased afterload (SVR). **NEET-PG High-Yield Pearls:** * **Blood Pressure:** Despite increased cardiac output, BP typically **decreases** in the first and second trimesters (due to decreased SVR), reaching its nadir at 24 weeks before returning to pre-pregnancy levels at term. * **Heart Sounds:** A physiological S3 and a systolic ejection murmur (grade 1 or 2) are considered normal in pregnancy. A diastolic murmur is **always** pathological. * **Positioning:** Cardiac output is highest in the **left lateral position** because it relieves the compression of the inferior vena cava by the gravid uterus (preventing Supine Hypotension Syndrome).

Question 183: Corpus luteum in the first 6 weeks of pregnancy is maintained by?

A. Beta-hCG (Correct Answer)
B. Estrogen
C. Progesterone
D. Human placental lactogen

Explanation: **Explanation:** The **Corpus Luteum (CL)** is essential for the maintenance of early pregnancy as it produces the progesterone required to support the decidua. In a non-pregnant cycle, the CL regresses after 14 days due to a lack of LH. However, if fertilization occurs, the developing syncytiotrophoblast secretes **Human Chorionic Gonadotropin (hCG)**. **Why Beta-hCG is correct:** hCG is structurally similar to Luteinizing Hormone (LH) and binds to the LH/hCG receptors on the corpus luteum. This "rescues" the CL from luteolysis, maintaining its functional integrity for the first **6–8 weeks** of gestation. After this period, the placenta takes over progesterone production (the **luteo-placental shift**). **Why the other options are incorrect:** * **Estrogen:** While produced by the CL, it does not maintain it. Estrogen levels rise during pregnancy to support uterine growth and breast development. * **Progesterone:** This is the *product* of the CL, not the stimulator. It is vital for maintaining pregnancy, but its secretion depends on the stimulation of the CL by hCG. * **Human Placental Lactogen (hPL):** Also known as Human Chorionic Somatomammotropin (hCS), it is involved in fetal growth and maternal insulin resistance (diabetogenic effect) but has no role in maintaining the CL. **High-Yield Clinical Pearls for NEET-PG:** * **Luteo-placental shift:** Occurs between **7–10 weeks**. If the corpus luteum is removed before 7 weeks without progesterone supplementation, abortion will occur. * **hCG Levels:** hCG is detectable in maternal serum **8–9 days after fertilization** (or 21–22 days of LMP). * **Doubling Time:** In a healthy pregnancy, serum beta-hCG levels double every **48–72 hours**. * **Peak Levels:** hCG reaches its peak at **8–10 weeks** (approx. 100,000 mIU/mL) and then declines to a plateau.

Question 184: All of the following may be observed in a normal pregnancy EXCEPT:

A. Fall in serum iron concentration
B. Increase in serum iron binding capacity
C. Increase in blood viscosity (Correct Answer)
D. Increase in blood oxygen carrying capacity

Explanation: In normal pregnancy, the cardiovascular and hematological systems undergo significant physiological adaptations to support the growing fetus. **Explanation of the Correct Answer (C):** During pregnancy, **plasma volume increases by approximately 40–50%**, whereas **red cell mass increases by only 20–30%**. This disproportionate increase leads to **hemodilution** (physiological anemia of pregnancy). Because the plasma volume expands more than the cellular components, the **blood viscosity actually decreases**. This reduction in viscosity lowers peripheral vascular resistance, ensuring smoother microcirculatory flow to the placenta and vital organs. Therefore, an *increase* in blood viscosity is pathological, not physiological. **Analysis of Incorrect Options:** * **A. Fall in serum iron concentration:** Despite the increase in red cell mass, the demand for iron by the fetus and the expanding maternal blood volume often exceeds dietary intake, leading to a typical fall in serum iron levels. * **B. Increase in serum iron binding capacity:** As iron stores deplete and the liver increases the production of transferrin, the Total Iron Binding Capacity (TIBC) increases. This is a classic physiological response to the increased iron demand. * **D. Increase in blood oxygen carrying capacity:** Although there is hemodilution, the absolute total red cell mass and total hemoglobin increase. This enhances the total oxygen-carrying capacity of the blood to meet the metabolic demands of the mother and fetus. **High-Yield Clinical Pearls for NEET-PG:** * **Plasma Volume:** Starts increasing at 6 weeks, peaks at 32–34 weeks. * **Hematocrit:** Decreases due to hemodilution (lowest at 30–32 weeks). * **ESR:** Increases physiologically in pregnancy due to increased fibrinogen levels. * **Clotting Factors:** Pregnancy is a **hypercoagulable state**; all factors increase except Factors XI and XIII. Protein S levels decrease.

Question 185: Which of the following is FALSE regarding hyperemesis gravidarum?

A. Allergic basis is suggested.
B. Hormonal imbalance may be a cause.
C. Small heart is an incidental finding. (Correct Answer)
D. May show manifestations of Wernicke's encephalopathy.

Explanation: ### Explanation **Hyperemesis Gravidarum (HG)** is a severe form of nausea and vomiting in pregnancy characterized by dehydration, electrolyte imbalance, and weight loss. **1. Why Option C is the Correct (False) Statement:** The finding of a **"small heart"** on X-ray or autopsy in patients with severe HG is **not an incidental finding**. It is a pathological sign of **brown atrophy of the heart**, resulting from prolonged starvation, severe malnutrition, and chronic dehydration. The heart undergoes atrophy due to the body's catabolic state, where it breaks down its own tissues for energy. **2. Analysis of Other Options:** * **Option A (Allergic basis):** This is a recognized theory. HG is sometimes considered an immunological or allergic reaction to the "foreign" proteins of the chorionic villi or fetal antigens. * **Option B (Hormonal imbalance):** This is the most widely accepted etiology. High levels of **hCG** (especially in molar pregnancies or twins) and **Estrogen** are strongly associated with the severity of vomiting. * **Option D (Wernicke’s encephalopathy):** This is a dreaded complication of HG. Persistent vomiting leads to **Vitamin B1 (Thiamine) deficiency**. The classic triad includes ataxia, ophthalmoplegia, and confusion. **3. High-Yield Clinical Pearls for NEET-PG:** * **Metabolic Profile:** HG typically causes **Metabolic Alkalosis** (due to loss of HCl) with **Hypokalemia** and **Hyponatremia**. * **Ketonuria:** The presence of ketones in urine is a hallmark of HG, indicating starvation. * **Liver Function:** Mild elevation of serum bilirubin and transaminases may occur. * **Management:** The first-line drug is **Pyridoxine (Vit B6) + Doxylamine**. If Wernicke’s is suspected, always give Thiamine **before** IV Dextrose to prevent worsening of neurological symptoms.

Question 186: Clomiphene citrate is not known to produce which of the following effects in a 30-year-old female?

A. Hot flushes
B. Ovulation
C. Decreased FSH and LH secretion (Correct Answer)
D. Polycystic ovaries

Explanation: **Explanation:** **Mechanism of Action and the Correct Answer:** Clomiphene Citrate (CC) is a Selective Estrogen Receptor Modulator (SERM). Its primary action is to act as a **competitive antagonist** at the estrogen receptors in the hypothalamus and pituitary gland. By blocking the negative feedback of endogenous estrogen, the body perceives a "hypoestrogenic" state. This triggers the pituitary gland to **increase** the secretion of **FSH and LH** (gonadotropins), which stimulates follicular development in the ovaries. Therefore, **Option C** is the correct answer because Clomiphene increases, rather than decreases, FSH and LH levels. **Analysis of Incorrect Options:** * **A. Hot flushes:** This is the most common side effect (approx. 10%). It occurs due to the anti-estrogenic effect of the drug on the thermoregulatory center in the hypothalamus. * **B. Ovulation:** This is the intended therapeutic effect. The rise in FSH leads to follicular growth, and the subsequent rise in estrogen eventually triggers an LH surge, leading to ovulation in 70-80% of patients. * **D. Polycystic ovaries:** Clomiphene causes ovarian stimulation. In some cases, this can lead to the formation of multiple follicular cysts or, in severe cases, Ovarian Hyperstimulation Syndrome (OHSS), making the ovaries appear polycystic or enlarged. **High-Yield NEET-PG Pearls:** * **First-line treatment:** Clomiphene is a traditional first-line drug for ovulation induction in PCOS (though Letrozole is now preferred in many guidelines due to higher live birth rates). * **Dose:** Usually started at 50 mg/day for 5 days, beginning on Day 2, 3, 4, or 5 of the menstrual cycle. * **Anti-estrogenic effects:** It can cause thinning of the endometrium and thickening of cervical mucus, which may lead to a "conception-ovulation gap" (high ovulation rate but lower pregnancy rate). * **Multiple Pregnancy:** There is an increased risk (approx. 5-10%), primarily twins.

Question 187: Which clotting factor is not increased in pregnancy?

A. Factor 2
B. Factor 7
C. Factor 10
D. Factor 11 (Correct Answer)

Explanation: **Explanation:** Pregnancy is a **hypercoagulable state** characterized by an increase in most procoagulant factors, a decrease in natural anticoagulants, and a reduction in fibrinolytic activity. This physiological adaptation serves to minimize blood loss during placental separation at delivery. **Why Factor 11 is the Correct Answer:** While most clotting factors rise during pregnancy, **Factor XI (11) and Factor XIII (13)** are notable exceptions. Factor XI levels actually **decrease** (by approximately 20-30%) or remain unchanged during pregnancy. Factor XIII also decreases significantly, reaching about 50% of non-pregnant levels by term. **Analysis of Incorrect Options:** * **Factor 2 (Prothrombin):** Levels of Factor II show a mild to moderate **increase** during pregnancy. * **Factor 7:** This factor shows the most dramatic rise among all clotting factors, often increasing by up to 100-200% of pre-pregnancy levels. * **Factor 10:** Along with Factors VII, VIII, IX, and XII, Factor X levels **increase** significantly to facilitate the clotting cascade. **High-Yield NEET-PG Pearls:** * **Factors that Increase:** I (Fibrinogen - increases by 50%), II, VII, VIII, IX, X, and XII. * **Factors that Decrease:** XI, XIII, and **Antithrombin III**. * **Protein S:** Levels of **Free Protein S decrease** significantly (a common exam trap), while Protein C remains relatively unchanged. * **Fibrinogen:** It is the most significantly increased factor by mass (reaching 400-600 mg/dL). * **ESR:** The Erythrocyte Sedimentation Rate (ESR) is physiologically **increased** in pregnancy due to the rise in fibrinogen.

Question 188: Serum testosterone levels exceeding 200 ng/dL is suggestive of which condition?

A. Polycystic Ovary Syndrome (PCOS)
B. Adrenal tumor (Correct Answer)
C. Metabolic syndrome
D. Ovarian atresia

Explanation: **Explanation:** In clinical practice, the degree of androgen elevation is a critical diagnostic marker for differentiating between functional and neoplastic causes of hyperandrogenism. **1. Why Adrenal Tumor is Correct:** Serum testosterone levels **exceeding 200 ng/dL** are highly suspicious for an **androgen-secreting tumor**, most commonly of ovarian or adrenal origin (e.g., Sertoli-Leydig cell tumor or Adrenal Cortical Carcinoma). While PCOS causes mild to moderate elevations, a rapid onset of virilization (clitoromegaly, deepening of voice) and testosterone levels >200 ng/dL necessitate imaging (CT/MRI or Ultrasound) to rule out a malignancy. **2. Why Other Options are Incorrect:** * **Polycystic Ovary Syndrome (PCOS):** This is the most common cause of hyperandrogenism, but testosterone levels are typically mildly elevated (usually **<150 ng/dL**). Levels >200 ng/dL are rare in PCOS. * **Metabolic Syndrome:** While often associated with PCOS and insulin resistance (which lowers SHBG and increases free testosterone), it does not independently cause extreme elevations of total testosterone. * **Ovarian Atresia:** This refers to the natural degeneration of follicles. It leads to a decrease in estrogen rather than a pathological increase in testosterone. **Clinical Pearls for NEET-PG:** * **Cut-off Values:** Testosterone **>200 ng/dL** suggests a tumor. DHEAS **>700 µg/dL** specifically suggests an **adrenal source/tumor**. * **Rapid Onset:** If symptoms of virilization appear rapidly (within 6 months), always suspect a tumor over PCOS. * **First-line Investigation:** For suspected androgen-secreting tumors, transvaginal ultrasound (TVS) is often the initial step to look for ovarian masses, followed by adrenal imaging.

Question 189: Which of the following changes that occur in the renal system during pregnancy is FALSE?

A. The renal calyces and ureters show significant dilatation.
B. Pregnancy-induced changes are responsible for an increased risk of upper urinary tract infections.
C. There is an increased glomerular filtration rate.
D. The kidneys become smaller compared to their pre-pregnant size. (Correct Answer)

Explanation: **Explanation** **1. Why Option D is the Correct (False) Statement:** During pregnancy, the kidneys do not shrink; they actually **increase in size**. The renal length increases by approximately **1–1.5 cm**, and the overall renal volume increases by up to 30%. This enlargement is primarily due to increased renal blood flow (hypervolemia) and interstitial edema, rather than cellular hyperplasia. **2. Analysis of Incorrect Options (True Statements):** * **Option A:** Progesterone causes smooth muscle relaxation, leading to the dilatation of renal calyces, renal pelvis, and ureters (**Hydroureter and Hydronephrosis of pregnancy**). This is more pronounced on the **right side** due to dextrorotation of the uterus and the cushioning effect of the sigmoid colon on the left. * **Option B:** The combination of urinary stasis (due to ureteral dilatation) and glycosuria/aminoaciduria creates a fertile ground for bacterial growth. This significantly increases the risk of **Pyelonephritis** (upper UTI) in pregnant women with asymptomatic bacteriuria. * **Option C:** Renal plasma flow increases by 50–80%, leading to a **40–50% increase in the Glomerular Filtration Rate (GFR)**. This begins as early as the first trimester. **3. High-Yield Clinical Pearls for NEET-PG:** * **Serum Creatinine:** Due to the increased GFR, normal serum creatinine levels are **lower** in pregnancy (0.4–0.8 mg/dL). A value of 0.9 mg/dL, which is normal in non-pregnant adults, may indicate renal impairment in a pregnant patient. * **Glucosuria:** It is common and considered physiological in pregnancy because the increased GFR exceeds the tubular reabsorptive capacity for glucose. * **Positioning:** The GFR is highest in the **lateral recumbent position** and decreases when supine due to aortocaval compression.

Question 190: Which of the following statements regarding gestational diabetes is true?

A. Gestational diabetes confers an increased risk of congenital malformations.
B. If HbA1c is less than 6%, there is no risk of congenital malformations.
C. As pre-conceptional glucose control worsens, the incidence of congenital malformations increases. (Correct Answer)
D. The highest risk for congenital malformations is seen with an HbA1c level between 7 and 8.

Explanation: ### Explanation **1. Why Option C is Correct:** The risk of congenital malformations in diabetic pregnancies is directly proportional to the level of glycemic control during the period of **organogenesis** (the first 8 weeks of gestation). As pre-conceptional and early first-trimester glucose control worsens (indicated by higher HbA1c levels), the incidence of major malformations increases linearly. Hyperglycemia induces oxidative stress and alters gene expression during critical developmental windows, leading to structural defects. **2. Why the Other Options are Incorrect:** * **Option A:** By definition, **Gestational Diabetes Mellitus (GDM)** develops in the second or third trimester (usually after 24 weeks), *after* organogenesis is complete. Therefore, GDM does **not** increase the risk of congenital malformations. This risk is exclusive to **Pre-gestational (Overt) Diabetes**. * **Option B:** While a lower HbA1c reduces risk, there is no "absolute zero" threshold. Even with an HbA1c < 6%, the risk of malformations is approximately 2–3%, which is similar to the baseline risk in the general population. * **Option D:** The risk is not highest at 7–8%. The risk continues to climb as HbA1c increases; the highest risk (up to 20–25%) is seen when HbA1c levels exceed **10%**. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most Common Malformation:** Cardiovascular anomalies (e.g., VSD, Transposition of Great Arteries). * **Most Specific Malformation:** **Caudal Regression Syndrome** (Sacral agenesis), though rare, is highly pathognomonic for diabetic embryopathy. * **Target HbA1c:** Ideally, HbA1c should be **< 6.0–6.5%** before conception to minimize teratogenic risks. * **Screening:** GDM is typically screened at **24–28 weeks** using the OGTT (DIPSI or IADPSG criteria).

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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