Endocrinology of Pregnancy — MCQs

A mother presented with complaints of anxiety, intolerance to heat, fatigue, increased appetite with minimal weight gain, and tremor. She also has a heart rate of 100 bpm and bulging eyes. These findings suggest a hyperthyroid state. Based on the mother's condition, what is the baby most likely at risk for developing?

Q219Easy

What is the treatment of choice for prenatal congenital adrenal hyperplasia?

Q220Easy

What is the drug of choice for the prevention of seizures in a patient with severe preeclampsia?

Endocrinology of Pregnancy Indian Medical PG Practice Questions and MCQs

Question 211: What does Spinnbarkeit refer to?

A. Cervical mucus (Correct Answer)
B. Uterine gland thickness
C. Cervical os appearance
D. Proliferation of breast alveoli

Explanation: **Explanation:** **Spinnbarkeit** refers to the **stretchability or elasticity of cervical mucus**. This physical property is a hallmark of the ovulatory phase and early pregnancy under the influence of high estrogen levels. 1. **Why Option A is correct:** Under the influence of **estrogen**, cervical mucus becomes thin, watery, clear, and highly elastic. This "Spinnbarkeit effect" allows the mucus to be stretched into a long thread (usually 8–12 cm) between two glass slides or fingers. This change is physiologically designed to facilitate the easy passage of sperm into the uterine cavity during the fertile window. 2. **Why other options are incorrect:** * **Option B:** Uterine gland thickness is a histological feature of the endometrium (proliferative vs. secretory phases), not a physical property of mucus. * **Option C:** Cervical os appearance changes (e.g., the "fetal head" sign or "O" sign), but Spinnbarkeit specifically describes the consistency of the secretion, not the anatomy of the os. * **Option D:** Proliferation of breast alveoli is primarily mediated by progesterone and prolactin, unrelated to cervical mucus elasticity. **High-Yield Clinical Pearls for NEET-PG:** * **Ferning Pattern:** High estrogen also causes the mucus to crystallize into a "palm-leaf" or fern-like pattern when dried on a slide (due to high sodium chloride content). * **Progesterone Effect:** Progesterone (dominant in the luteal phase or pregnancy) makes the mucus thick, viscid, and cellular, **abolishing** both Spinnbarkeit and Ferning. * **Inspissation:** The process of mucus becoming thick and forming a "mucus plug" under progesterone is called inspissation, which acts as a barrier to infection.

Question 212: Halban disease is due to?

A. Persistent corpus luteum (Correct Answer)
B. Deficient corpus luteum
C. Persistent trophoblast
D. Deficient trophoblast

Explanation: **Explanation:** **Halban Disease**, also known as **Persistent Corpus Luteum**, is a clinical condition where the corpus luteum fails to regress at the end of the menstrual cycle. 1. **Why Option A is Correct:** Under normal physiological conditions, if fertilization does not occur, the corpus luteum undergoes luteolysis (degeneration). In Halban disease, the corpus luteum remains functional and continues to secrete **progesterone**. This persistent hormonal activity prevents the onset of menstruation, leading to a clinical triad of **delayed menses (amenorrhea), pelvic pain, and a tender adnexal mass.** This presentation mimics an ectopic pregnancy, making it a crucial differential diagnosis in clinical practice. 2. **Why Other Options are Incorrect:** * **Option B (Deficient corpus luteum):** This refers to Luteal Phase Defect (LPD), which leads to low progesterone levels, early onset of menses, or recurrent early pregnancy loss, rather than a persistent mass or delayed menses. * **Options C & D (Trophoblast):** Trophoblastic tissue is related to pregnancy (Gestational Trophoblastic Disease). Halban disease occurs in the **absence** of pregnancy; it is a functional ovarian abnormality, not a placental or trophoblastic one. **High-Yield Clinical Pearls for NEET-PG:** * **Halban’s Triad:** Delayed menses + Unilateral pelvic pain + Adnexal mass. * **Differential Diagnosis:** Must be differentiated from **Ectopic Pregnancy**. The key differentiator is a **negative urine/serum pregnancy test (hCG)** in Halban disease. * **Management:** It is usually self-limiting; the cyst typically regresses spontaneously within one or two cycles.

Question 213: Which of the following is an absolute contraindication for the treatment of thyrotoxicosis in a 6-month pregnant patient?

A. Antithyroid drug
B. Radioactive iodine (I-131) therapy (Correct Answer)
C. Telepaque
D. Surgery

Explanation: **Explanation:** The correct answer is **Radioactive iodine (I-131) therapy**. **Why it is the correct answer:** Radioactive iodine (I-131) is **absolutely contraindicated** during pregnancy because it readily crosses the placenta. By the 10th–12th week of gestation, the fetal thyroid gland begins to concentrate iodine. Administration of I-131 after this period leads to the permanent destruction of the fetal thyroid gland, resulting in **congenital hypothyroidism (cretinism)** and potential neurodevelopmental delays. **Why the other options are incorrect:** * **Antithyroid drugs (ATDs):** These are the first-line treatment for thyrotoxicosis in pregnancy. While they cross the placenta, they are used at the lowest effective dose. (Note: PTU is preferred in the 1st trimester; Methimazole is preferred in the 2nd and 3rd trimesters). * **Telepaque (Iopanoic acid):** This is an iodinated contrast agent sometimes used for the rapid control of severe thyrotoxicosis. While not a first-line long-term therapy, it is not an absolute contraindication like I-131. * **Surgery (Subtotal Thyroidectomy):** Surgery is indicated if the patient is allergic to ATDs or requires high doses that threaten the fetus. The safest time for surgery is the **second trimester** (the patient in the question is 6 months/2nd trimester). **High-Yield Clinical Pearls for NEET-PG:** * **Fetal Thyroid Activity:** Starts at **12 weeks** gestation. * **Drug of Choice:** **Propylthiouracil (PTU)** in the 1st trimester (to avoid Methimazole embryopathy like *aplasia cutis*); **Methimazole** in the 2nd and 3rd trimesters (to avoid PTU-induced maternal hepatotoxicity). * **Goal of Therapy:** Maintain maternal Free T4 levels at the **upper limit of the normal non-pregnant range** to minimize the risk of fetal hypothyroidism. * **Beta-blockers:** Propranolol can be used for symptomatic relief but long-term use is associated with IUGR.

Question 214: Hypothyroidism in pregnancy causes which of the following complications?

A. Macrosomia
B. Polyhydramnios
C. Mental retardation (Correct Answer)
D. Abortion

Explanation: **Explanation:** **Correct Answer: C. Mental retardation** The fetal thyroid gland only begins to function and concentrate iodine around the **12th week of gestation**. Prior to this, the fetus is entirely dependent on the transplacental transfer of maternal thyroxine (T4) for brain development. Thyroid hormones are critical for neuronal migration, synaptogenesis, and myelination. Maternal hypothyroidism during this crucial window leads to irreversible neurocognitive deficits and **mental retardation** (cretinism) in the offspring. **Analysis of Incorrect Options:** * **A. Macrosomia:** This is typically associated with **Gestational Diabetes Mellitus (GDM)** due to fetal hyperinsulinemia. Hypothyroidism is more commonly associated with Low Birth Weight (LBW) or Intrauterine Growth Restriction (IUGR). * **B. Polyhydramnios:** This is associated with conditions like maternal diabetes, fetal structural anomalies (e.g., esophageal atresia), or multiple gestations. Hypothyroidism is more likely to be associated with **Oligohydramnios** if it leads to placental insufficiency. * **D. Abortion:** While severe untreated hypothyroidism *can* increase the risk of early pregnancy loss, it is a non-specific complication. In the context of NEET-PG questions, **Mental Retardation** is the "hallmark" and most specific developmental consequence emphasized for maternal hypothyroidism. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Levothyroxine is the treatment of choice. * **Dose Adjustment:** Requirements of Levothyroxine increase by **30-50%** during pregnancy. * **Target TSH:** Ideally kept <2.5 mIU/L in the first trimester and <3.0 mIU/L in the second and third trimesters. * **Screening:** Universal screening for thyroid dysfunction in pregnancy is currently recommended in India due to the high prevalence of iodine deficiency.

Question 215: Which of the following medications can be safely used in pregnancy?

A. ACE inhibitors
B. Aldosterone
C. Angiotensin receptor antagonists
D. Propylthiouracil (Correct Answer)

Explanation: **Explanation:** **Propylthiouracil (PTU)** is the drug of choice for managing hyperthyroidism during the **first trimester** of pregnancy. While both PTU and Methimazole are effective, PTU is preferred early in pregnancy because it is more highly protein-bound, resulting in less placental transfer compared to Methimazole. This reduces the risk of Methimazole-associated embryopathy (e.g., Aplasia cutis, choanal atresia, and esophageal atresia). In the second and third trimesters, many clinicians switch to Methimazole to avoid the rare risk of PTU-induced maternal hepatotoxicity. **Why the other options are incorrect:** * **ACE Inhibitors (e.g., Enalapril) & Angiotensin Receptor Antagonists (ARBs):** These are strictly **contraindicated** (Category D/X) in pregnancy, especially during the second and third trimesters. They interfere with fetal renal development, leading to fetal renal dysgenesis, oligohydramnios, pulmonary hypoplasia, and calvarial (skull) defects. * **Aldosterone:** While not a standard medication, mineralocorticoid antagonists (like Spironolactone) are generally avoided due to their anti-androgenic effects, which can potentially cause the feminization of a male fetus. **NEET-PG High-Yield Pearls:** * **Drug of Choice for Hyperthyroidism:** PTU in the 1st trimester; Methimazole in the 2nd and 3rd trimesters. * **Antihypertensives safe in pregnancy:** Labetalol (DOC), Methyldopa, Nifedipine, and Hydralazine. * **Teratogenic effect of Methimazole:** Aplasia cutis (congenital absence of skin, usually on the scalp). * **ACEI Fetopathy:** Characterized by "Oligohydramnios sequence" and hypocalvaria.

Question 216: For the evaluation of gonadotropin levels, select the most appropriate day of a normal 28-day menstrual cycle for a woman with 5-day menstrual periods.

A. Day 3 (Correct Answer)
B. Day 8
C. Day 14
D. Day 21

Explanation: **Explanation:** The evaluation of gonadotropins (FSH and LH) is a cornerstone in assessing ovarian reserve and the hypothalamic-pituitary-ovarian (HPO) axis. **Why Day 3 is Correct:** The goal of testing gonadotropins is to measure **"Basal Levels."** On Day 2 or 3 of the menstrual cycle (early follicular phase), estrogen and progesterone are at their lowest points. This lack of negative feedback allows the pituitary to secrete FSH at its baseline level. A Day 3 FSH level is the most reliable predictor of ovarian reserve; elevated levels (>10–12 mIU/mL) suggest diminished ovarian reserve (DOR). **Analysis of Incorrect Options:** * **Day 8 (Mid-follicular phase):** Dominant follicle selection has begun. Rising estradiol levels start to suppress FSH via negative feedback, making the reading inaccurate for baseline assessment. * **Day 14 (Ovulatory phase):** This coincides with the **LH surge** and a smaller FSH surge. While useful for documenting ovulation, it does not reflect basal endocrine status or ovarian reserve. * **Day 21 (Mid-luteal phase):** This is the ideal time to measure **Serum Progesterone** (to confirm ovulation) but is inappropriate for gonadotropins due to high progesterone levels suppressing FSH/LH. **NEET-PG High-Yield Pearls:** * **Day 2/3 FSH:** Best for Ovarian Reserve. * **Day 21 Progesterone:** Best to confirm Ovulation (>3 ng/mL indicates ovulation). * **AMH (Anti-Müllerian Hormone):** Unlike FSH, AMH can be tested on **any day** of the cycle as it is cycle-independent and is currently considered the most sensitive marker for ovarian reserve. * **LH:FSH Ratio:** Normally 1:1; a ratio >2:1 or 3:1 is a classic (though not diagnostic) finding in **PCOS**.

Question 217: As per ACOG criteria, what is the 2-hour plasma glucose threshold in mg/dL to diagnose gestational diabetes using a Glucose Tolerance Test (GTT)?

A. 180
B. 155 (Correct Answer)
C. 140
D. 126

Explanation: **Explanation:** The diagnosis of Gestational Diabetes Mellitus (GDM) according to ACOG (American College of Obstetricians and Gynecologists) typically follows the **Two-Step Strategy**. This involves an initial 50g Glucose Challenge Test (GCT), followed by a diagnostic **100g, 3-hour Oral Glucose Tolerance Test (OGTT)** for those who screen positive. According to the **Carpenter-Coustan criteria** (the most widely used thresholds), GDM is diagnosed if at least two of the following plasma glucose values are met or exceeded: * **Fasting:** 95 mg/dL * **1-hour:** 180 mg/dL * **2-hour: 155 mg/dL** (Correct Answer) * **3-hour:** 140 mg/dL **Analysis of Incorrect Options:** * **A. 180 mg/dL:** This is the threshold for the **1-hour** value in the 3-hour OGTT. * **C. 140 mg/dL:** This is the threshold for the **3-hour** value in the 3-hour OGTT. It is also the common cutoff used for the 1-hour 50g GCT screening. * **D. 126 mg/dL:** This is the standard threshold for **Fasting Plasma Glucose** to diagnose overt (pre-existing) Diabetes Mellitus, not GDM. **High-Yield Pearls for NEET-PG:** 1. **DIPSI Criteria (Indian Context):** Diagnosis is made if the 2-hour plasma glucose is **≥140 mg/dL** after a 75g glucose load, regardless of the last meal. This is a single-step procedure. 2. **IADPSG/WHO Criteria:** Uses a 75g OGTT. Diagnosis is made if **any one** value is met: Fasting ≥92, 1-hr ≥180, or 2-hr ≥153 mg/dL. 3. **Best Time to Screen:** 24–28 weeks of gestation. 4. **First-line Management:** Medical Nutrition Therapy (MNT) for 1–2 weeks; if targets aren't met, Insulin is the drug of choice.

Question 218: A mother presented with complaints of anxiety, intolerance to heat, fatigue, increased appetite with minimal weight gain, and tremor. She also has a heart rate of 100 bpm and bulging eyes. These findings suggest a hyperthyroid state. Based on the mother's condition, what is the baby most likely at risk for developing?

A. Heart failure (Correct Answer)
B. Constipation
C. Third-degree heart block
D. Macrocephaly

Explanation: **Explanation:** The clinical presentation of anxiety, heat intolerance, tremors, tachycardia, and **exophthalmos (bulging eyes)** strongly indicates **Graves' disease**. In Graves' disease, the body produces **Thyroid Stimulating Immunoglobulins (TSI)**. These are IgG antibodies that can cross the placenta and stimulate the fetal thyroid gland, leading to **Neonatal Thyrotoxicosis**. **1. Why Heart Failure is Correct:** Excessive thyroid hormone in the fetus/neonate causes a hypermetabolic state and severe tachycardia. This high-output state can lead to **fetal or neonatal heart failure**, hydrops fetalis, and even intrauterine growth restriction (IUGR). In the neonate, this manifests as tachycardia, irritability, poor weight gain, and potentially fatal cardiac failure if untreated. **2. Why Incorrect Options are Wrong:** * **Constipation:** This is a feature of *hypothyroidism*. Neonatal thyrotoxicosis causes increased bowel frequency or diarrhea. * **Third-degree heart block:** This is classically associated with **Neonatal Lupus**, caused by the transplacental passage of anti-Ro (SSA) and anti-La (SSB) antibodies, not hyperthyroidism. * **Macrocephaly:** Hyperthyroidism is more likely to cause **craniosynostosis** (premature closure of sutures) and microcephaly rather than macrocephaly. **Clinical Pearls for NEET-PG:** * **TSI (Thyroid Stimulating Immunoglobulins):** The specific antibody responsible for Graves' disease that crosses the placenta. * **Treatment:** Propylthiouracil (PTU) is preferred in the 1st trimester (due to Methimazole's association with *Aplasia Cutis*); Methimazole is preferred in the 2nd and 3rd trimesters. * **Fetal Goiter:** Can occur due to either uncontrolled maternal hyperthyroidism or over-treatment with anti-thyroid drugs (which also cross the placenta).

Question 219: What is the treatment of choice for prenatal congenital adrenal hyperplasia?

A. Hydrocortisone
B. Dexamethasone (Correct Answer)
C. Betamethasone
D. Prednisolone

Explanation: **Explanation:** The primary goal of prenatal treatment for **Congenital Adrenal Hyperplasia (CAH)**, specifically 21-hydroxylase deficiency, is to prevent the **virilization of a female fetus** by suppressing the fetal pituitary-adrenal axis. **1. Why Dexamethasone is the Correct Answer:** Dexamethasone is a potent glucocorticoid that **crosses the placenta** without being inactivated by the placental enzyme **11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2)**. By reaching the fetal circulation, it suppresses fetal ACTH secretion, thereby reducing the production of adrenal androgens that cause ambiguous genitalia in female fetuses. Treatment must be started empirically before the 9th week of gestation (ideally by the 6th week) to be effective. **2. Why Other Options are Incorrect:** * **Hydrocortisone and Prednisolone:** These are the drugs of choice for treating CAH *postnatally* or managing the mother. However, they are extensively metabolized/inactivated by placental 11β-HSD2 and do not reach the fetus in therapeutic concentrations. * **Betamethasone:** While it also crosses the placenta, it is primarily used for inducing fetal lung maturity in preterm labor. Dexamethasone is the established gold standard for prenatal CAH suppression in clinical protocols. **Clinical Pearls for NEET-PG:** * **Timing:** Treatment must start **before 9 weeks** (before sexual differentiation begins). * **Diagnosis:** If the fetus is later confirmed to be male or an unaffected female via CVS or amniocentesis, dexamethasone is discontinued. * **Maternal Side Effects:** Long-term dexamethasone use can cause maternal weight gain, striae, and gestational diabetes. * **Enzyme Deficiency:** 21-hydroxylase deficiency is the most common cause (90-95%) of CAH.

Question 220: What is the drug of choice for the prevention of seizures in a patient with severe preeclampsia?

A. Phenytoin
B. Magnesium sulphate (Correct Answer)
C. Diazepam
D. Nifedipine

Explanation: **Explanation:** **Magnesium sulphate ($MgSO_4$)** is the gold standard and drug of choice for both the **prevention (prophylaxis)** of seizures in severe preeclampsia and the **control** of seizures in eclampsia. Its superiority over other anticonvulsants was definitively established by the **MAGPIE trial**. It acts primarily by blocking NMDA receptors in the brain, increasing the seizure threshold, and causing cerebral vasodilation to reduce ischemia. **Analysis of Incorrect Options:** * **A. Phenytoin:** While an effective antiepileptic, it is less effective than $MgSO_4$ in preventing eclamptic seizures and carries a higher risk of maternal toxicity and fetal side effects. * **C. Diazepam:** Formerly used for seizure control, it is now avoided as a first-line agent because it causes significant maternal respiratory depression and neonatal "Floppy Infant Syndrome." * **D. Nifedipine:** This is a Calcium Channel Blocker used as an **antihypertensive** to manage blood pressure in preeclampsia, but it has no anticonvulsant properties. **High-Yield Clinical Pearls for NEET-PG:** * **Regimen:** The **Pritchard Regimen** (IM) and **Zuspan Regimen** (IV) are the standard protocols. * **Therapeutic Window:** 4–7 mEq/L. * **Monitoring:** Always check for **Patellar reflex** (first sign of toxicity is loss of reflex), **Respiratory rate** (>12/min), and **Urine output** (>30 ml/hr) before each dose. * **Antidote:** **Calcium gluconate** (10 ml of 10% solution administered IV over 10 minutes). * **Excretion:** It is exclusively cleared by the kidneys; hence, dose adjustment is mandatory in renal failure.

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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