Endocrinology of Pregnancy Practice Questions

Q: All of the following are risk factors for hyperemesis gravidarum, EXCEPT?

Gestational diabetes. **Explanation:** Hyperemesis gravidarum (HG) is a severe form of nausea and vomiting in pregnancy characterized by weight loss, dehydration, and electrolyte imbalances. The underlying pathophysiology is primarily linked to high circulating levels of **Human Chorionic Gonadotropin (hCG)** and estrogen. **Why Gestational Diabetes is the Correct Answer:** Gestational Diabetes Mellitus (GDM) is **not** a risk factor for hyperemesis gravidarum. In fact, some studies suggest a potential inverse relationship, as HG is associated with a lower BMI and lower caloric intake in early pregnancy, whereas GDM is more common in patients with higher BMI and metabolic syndrome. **Analysis of Incorrect Options:** * **Molar Pregnancy (Hydatidiform Mole):** This condition involves an abnormal proliferation of trophoblasts, leading to pathologically high levels of hCG, which directly triggers the chemoreceptor trigger zone (CTZ). * **Twin Pregnancy:** Multiple gestations result in a larger placental mass and higher cumulative levels of hCG and estrogen compared to singleton pregnancies, significantly increasing the risk of HG. * **Hyperthyroidism:** hCG has a structural similarity to Thyroid Stimulating Hormone (TSH) and can weakly stimulate the TSH receptors (thyrotoxicosis of pregnancy). Conversely, pre-existing hyperthyroidism is associated with an increased risk of severe vomiting. **NEET-PG High-Yield Pearls:** * **Most common risk factor:** Previous history of hyperemesis gravidarum. * **Hormone most implicated:** hCG (specifically the peak levels between 8–12 weeks). * **Wernicke’s Encephalopathy:** A rare but serious complication of HG due to **Vitamin B1 (Thiamine)** deficiency; look for the triad of ataxia, ophthalmoplegia, and confusion. * **Electrolyte hallmark:** Hypokalemic, hypochloremic metabolic alkalosis.

Q: What is the characteristic change in the vagina during normal pregnancy?

Increased number of lactobacilli. **Explanation:** The vaginal environment undergoes significant physiological changes during pregnancy, primarily driven by high levels of **estrogen**. 1. **Why Option B is Correct:** Estrogen causes the vaginal epithelium to thicken and accumulate high levels of **glycogen**. *Lactobacillus acidophilus* (Döderlein’s bacilli) ferment this glycogen into **lactic acid**. This symbiotic relationship leads to a proliferation of lactobacilli, which serve as a protective mechanism against ascending infections. 2. **Why Option A is Incorrect:** Due to the increased production of lactic acid, the vaginal **pH decreases** (becomes more acidic), typically ranging between **3.5 to 6.0**. An increased pH would indicate an abnormality, such as Bacterial Vaginosis. 3. **Why Option C is Incorrect:** While glycogen content *does* increase, it is the **substrate** for the process, not the primary characteristic change listed in the context of the vaginal flora's response. In NEET-PG, when choosing between the "cause" (glycogen) and the "result" (lactobacilli/acidity), the biological shift in flora is considered the hallmark change. 4. **Why Option D is Incorrect:** The acidic environment created by lactobacilli is bacteriostatic, actually **decreasing** the colonization of pathogenic bacteria. **NEET-PG High-Yield Pearls:** * **Chadwick’s Sign:** The bluish discoloration of the vagina due to increased vascularity (seen at 6–8 weeks). * **Osiander’s Sign:** Increased pulsation felt through the lateral fornices due to increased vascularity. * **Leukorrhea of Pregnancy:** The normal, thin, milky-white vaginal discharge resulting from increased exfoliation of epithelial cells and cervical mucus. * **Clinical Note:** The high glycogen content predisposes pregnant women to **Moniliasis (Candidiasis)**, despite the acidic pH.

Q: Combination of Doxylamine with which of the following is considered the safest antiemetic drug in pregnancy?

Pyridoxine. **Explanation:** The combination of **Doxylamine (an H1-receptor antagonist) and Pyridoxine (Vitamin B6)** is recognized by the ACOG (American College of Obstetricians and Gynecologists) as the **first-line pharmacotherapy** for Nausea and Vomiting of Pregnancy (NVP) when conservative management fails. **Why Pyridoxine is Correct:** Pyridoxine is a water-soluble vitamin that plays a crucial role in amino acid metabolism. While its exact mechanism in reducing nausea is not fully understood, clinical trials have proven its efficacy and safety profile. The combination (formerly known as Diclegis/Bendectin) is the only FDA-approved medication specifically for NVP, categorized as **Category A** (safest) in pregnancy. **Analysis of Incorrect Options:** * **Palonosetron (A):** A second-generation 5-HT3 receptor antagonist. While Ondansetron is commonly used off-label, Palonosetron lacks extensive safety data in the first trimester. * **Aprepitant (C):** A substance P/neurokinin 1 (NK1) receptor antagonist used primarily for chemotherapy-induced nausea. It is not indicated for NVP. * **Domperidone (D):** A dopamine antagonist and prokinetic. It is generally avoided in the first trimester due to limited safety data and potential concerns regarding cardiac arrhythmias (QT prolongation). **High-Yield Clinical Pearls for NEET-PG:** * **First-line management of NVP:** Dietary modifications (small, frequent meals; ginger). * **First-line drug:** Pyridoxine monotherapy or Pyridoxine + Doxylamine. * **Hyperemesis Gravidarum (HG):** Defined by persistent vomiting, weight loss (>5%), and ketonuria. * **Wernicke’s Encephalopathy:** A rare but severe complication of HG due to **Thiamine (B1) deficiency**; always replenish Thiamine before giving IV glucose. * **Steroids:** Used as a last resort for refractory HG, but must be avoided before 10 weeks of gestation due to a potential risk of oral clefts.

Q: Human chorionic gonadotropin (hCG) can be estimated earliest by which method?

Radioimmunoassay. **Explanation:** **Why Radioimmunoassay (RIA) is the correct answer:** Radioimmunoassay is the most sensitive and specific method for detecting human chorionic gonadotropin (hCG). It utilizes the **beta-subunit (β-hCG)** principle, which prevents cross-reactivity with LH, FSH, and TSH. Due to its high sensitivity (detecting levels as low as 5 mIU/mL), it can identify hCG in maternal serum as early as **8 to 9 days after fertilization** (roughly 6 days before the missed period). This makes it the gold standard for the earliest possible detection of pregnancy. **Analysis of Incorrect Options:** * **Enzyme-linked immunosorbent assay (ELISA):** While widely used in modern clinical practice and "Home Pregnancy Tests" (Urine) due to speed and ease, it generally has a higher detection threshold than RIA. It typically becomes positive around the time of the missed period. * **Radioreceptor assay:** This method measures the biological activity of the hormone by its binding capacity to receptors. While sensitive, it cannot distinguish between hCG and LH, leading to lower specificity compared to RIA. * **Bioassay:** These are historical tests (e.g., Aschheim-Zondek, Friedman test) involving animal models. They are time-consuming, expensive, and lack the sensitivity required for early detection. **High-Yield Clinical Pearls for NEET-PG:** * **Doubling Time:** In a healthy intrauterine pregnancy, serum β-hCG levels double every **48 hours** during the first 8 weeks. * **Peak Levels:** hCG levels reach their peak at **8–10 weeks** (approx. 100,000 mIU/mL) and then decline to a plateau. * **Discriminatory Zone:** The level of hCG at which a gestational sac should be visible on TVS is **1500–2000 mIU/mL**. * **Source:** hCG is secreted by the **syncytiotrophoblast** cells of the developing placenta.

Q: Which of the following can be used in the management of cystitis in pregnancy, except?

Cefpodoxime 400 mg every 12 hours. **Explanation:** The management of acute cystitis in pregnancy requires antibiotics that are both safe for the fetus and effective against common uropathogens (primarily *E. coli*). **Why Option D is the correct answer:** The dosage provided for **Cefpodoxime (400 mg every 12 hours)** is incorrect. The standard therapeutic dose for treating cystitis in pregnancy is **100 mg every 12 hours** for 3–7 days. A 400 mg dose is excessively high for this indication and does not align with established obstetric guidelines (ACOG/IDSA). **Analysis of Incorrect Options:** * **Option A (Amoxicillin):** While resistance rates are increasing, Amoxicillin (500 mg 8–12 hourly) remains a Category B drug and is safe for use in pregnancy if the organism is susceptible. * **Option B (Cephalexin):** First-generation cephalosporins are a mainstay of treatment. The dose of 500 mg every 6–12 hours is standard and safe. * **Option C (Nitrofurantoin):** This is a first-line agent for cystitis. The 100 mg BD dose for 5–7 days is highly effective as it achieves high urinary concentrations. (Note: It should be avoided at term/during labor due to the risk of neonatal hemolytic anemia/G6PD deficiency). **High-Yield Clinical Pearls for NEET-PG:** * **Asymptomatic Bacteriuria (ASB):** Must always be treated in pregnancy (even if the patient has no symptoms) to prevent progression to pyelonephritis (20-30% risk if untreated). * **Drugs to Avoid:** * **Fluoroquinolones:** Risk of fetal cartilage damage. * **Trimethoprim:** Avoid in the 1st trimester (folate antagonist; neural tube defects). * **Sulfonamides:** Avoid in the 3rd trimester (risk of kernicterus). * **Test of Cure:** Always perform a follow-up urine culture 1–2 weeks after completing treatment in pregnant patients.

Q: What is the earliest time to detect human placental lactogen (hPL) in maternal serum?

3 weeks. **Explanation:** **Human Placental Lactogen (hPL)**, also known as human chorionic somatomammotropin (hCS), is a polypeptide hormone produced by the **syncytiotrophoblast** of the placenta. 1. **Why 3 weeks is correct:** hPL can be detected in maternal serum as early as **3 weeks post-fertilization** (approximately 5 weeks after the Last Menstrual Period). Its concentration rises steadily throughout pregnancy, paralleling the increase in placental mass, and reaches its peak near term (36–37 weeks). 2. **Why other options are incorrect:** * **12 weeks:** While hPL levels are easily measurable by the end of the first trimester, this is not the *earliest* detection point. * **24 & 28 weeks:** These represent periods of significant metabolic demand where hPL levels are high, but they occur long after the hormone first enters the maternal circulation. **High-Yield Clinical Pearls for NEET-PG:** * **Function:** hPL is a potent **"diabetogenic"** hormone. It antagonizes insulin action, leading to maternal lipolysis (releasing free fatty acids) and decreased glucose utilization. This ensures a steady supply of glucose for the fetus. * **Structure:** It is structurally and immunologically similar to **Growth Hormone (GH)** and **Prolactin**. * **Clinical Marker:** Because its level is directly proportional to placental weight, it was historically used as a marker for placental function (though now largely replaced by biophysical profiles). * **Disappearance:** It has a very short half-life (15–30 minutes) and disappears from maternal blood within hours of delivery.

Q: In early pregnancy, what is the typical doubling time of hCG concentrations in plasma?

48 hours. ### Explanation **Correct Option: B (48 hours)** Human Chorionic Gonadotropin (hCG) is a glycoprotein hormone produced by the syncytiotrophoblast. In a normal intrauterine pregnancy, serum hCG levels rise exponentially during the first trimester. The "doubling time" is a critical clinical marker used to assess pregnancy viability. In approximately 85% of viable early pregnancies, the hCG concentration increases by at least 66% every 48 hours, typically doubling every **1.5 to 2 days (48 hours)**. This rapid rise continues until it peaks at around 8–11 weeks of gestation (approximately 100,000 mIU/mL). **Analysis of Incorrect Options:** * **A (12 hours):** This is physiologically too rapid. Such an accelerated rise is not seen in normal human gestation. * **C & D (72–96 hours):** While the doubling time slows down as pregnancy progresses (taking about 3 days at 6–7 weeks and 4 days by 8 weeks), the *typical* doubling time used for clinical assessment in early pregnancy (before 6 weeks) is 48 hours. A rise slower than this often suggests an abnormal pregnancy (e.g., ectopic pregnancy or impending miscarriage). **High-Yield Clinical Pearls for NEET-PG:** * **Discriminatory Zone:** This is the hCG level above which a gestational sac should be visible on ultrasound. For Transvaginal Sonography (TVS), it is typically **1,500–2,000 mIU/mL**. * **Ectopic Pregnancy:** Suspect this if hCG levels rise sub-optimally (less than 66% in 48 hours) or plateau. * **Molar Pregnancy:** Characterized by abnormally high hCG levels (often >100,000 mIU/mL) for the calculated gestational age. * **Structure:** hCG shares a common **alpha (α) subunit** with LH, FSH, and TSH; its specificity is derived from the **beta (β) subunit**.

Q: Which hormone's level remains unchanged during pregnancy?

Plasma vasopressin. **Explanation:** The correct answer is **Plasma vasopressin (ADH)**. During pregnancy, the maternal body undergoes significant physiological adaptations, but the basal plasma concentration of vasopressin remains essentially **unchanged**. While the absolute levels of vasopressin do not change, the **osmotic threshold** for its release and the threshold for thirst are "reset" to a lower level (osmostat reset). This allows the body to maintain a new state of relative hypoosmolality (a drop of ~10 mOsm/kg) as normal during pregnancy. Additionally, the metabolic clearance of vasopressin increases significantly due to the production of **vasopressinase** by the placenta, but the pituitary compensates by increasing secretion, keeping the net plasma levels stable. **Why the other options are incorrect:** * **Prolactin:** Levels rise progressively (up to 10-fold) throughout pregnancy due to estrogenic stimulation of the maternal pituitary gland, preparing the breasts for lactation. * **Growth Hormone (GH):** While pituitary GH secretion decreases after the first trimester, **Placental Growth Hormone (hPGH)** rises significantly, becoming the dominant GH variant in maternal circulation by the second trimester. * **ACTH:** Maternal plasma ACTH levels rise steadily during pregnancy. This is driven by the placental production of CRH (Corticotropin-Releasing Hormone), which is refractory to feedback inhibition by cortisol. **NEET-PG High-Yield Pearls:** * **hCG:** Peaks at 8–10 weeks of gestation. * **hPL (Human Placental Lactogen):** Levels are directly proportional to placental mass; it is the primary hormone responsible for the "diabetogenic state" of pregnancy. * **Thyroid:** Total T3 and T4 increase (due to increased TBG), but **Free T3 and T4** remain relatively constant (or show a slight, transient rise in the first trimester due to hCG's weak TSH-like action).

Question 1

What is the most sensitive method for the quantitative measurement of human chorionic gonadotropin?

Accepted Answer

Radioimmunoassay

Answer

Paper chromatography

Answer

Latex particle test

Answer

Male toad test

Question 2

All of the following are risk factors for hyperemesis gravidarum, EXCEPT?

Accepted Answer

Gestational diabetes

Answer

Hyperthyroidism

Answer

Twin pregnancy

Answer

Molar pregnancy

Question 3

What is the characteristic change in the vagina during normal pregnancy?

Accepted Answer

Increased number of lactobacilli

Answer

Increased pH

Answer

Increased glycogen content

Answer

Increased number of pathogenic bacteria

Question 4

Combination of Doxylamine with which of the following is considered the safest antiemetic drug in pregnancy?

Accepted Answer

Pyridoxine

Answer

Palonosetron

Answer

Aprepitant

Answer

Domperidone

Question 5

Human chorionic gonadotropin (hCG) can be estimated earliest by which method?

Accepted Answer

Radioimmunoassay

Answer

Enzyme-linked immunosorbent assay (ELISA)

Answer

Radioreceptor assay

Answer

Bioassay

Question 6

In testicular feminisation syndrome, which of the following is true?

Accepted Answer

Normal breast size is observed

Answer

Buccal smear is chromatin positive

Answer

Menstruation is scanty and infrequent

Answer

Streak gonads are seen

Question 7

Which of the following can be used in the management of cystitis in pregnancy, except?

Accepted Answer

Cefpodoxime 400 mg every 12 hours

Answer

Amoxicillin 500 mg every 8-12 hours for 3-7 days

Answer

Cephalexin 500 mg every 6-12 hours for 3-7 days

Answer

Nitrofurantoin 100 mg every 12 hours for 5-7 days

Question 8

What is the earliest time to detect human placental lactogen (hPL) in maternal serum?

Accepted Answer

3 weeks

Answer

12 weeks

Answer

24 weeks

Answer

28 weeks

Question 9

In early pregnancy, what is the typical doubling time of hCG concentrations in plasma?

Accepted Answer

48 hours

Answer

12 hours

Answer

72 hours

Answer

96 hours

Question 10

Which hormone's level remains unchanged during pregnancy?

Accepted Answer

Plasma vasopressin

Answer

Prolactin

Answer

Growth hormone

Answer

ACTH

Endocrinology of Pregnancy — MCQs

Endocrinology of Pregnancy — MCQs

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