Endocrinology of Pregnancy — MCQs

Endocrinology of Pregnancy Indian Medical PG Practice Questions and MCQs

Question 131: Which of the following is NOT a feature of hyperprolactinemia?

A. Amenorrhea
B. Decreased milk production (Correct Answer)
C. Galactorrhea
D. Hypogonadotropic hypogonadism

Explanation: **Explanation:** The correct answer is **B. Decreased milk production**. Hyperprolactinemia is characterized by an excess of prolactin, the hormone primarily responsible for the synthesis and secretion of breast milk. Therefore, it leads to **increased** milk production (galactorrhea) rather than decreased production. **Why the other options are features of Hyperprolactinemia:** * **Amenorrhea & Hypogonadotropic Hypogonadism (Options A & D):** High levels of prolactin exert a negative feedback effect on the hypothalamus, inhibiting the pulsatile release of **GnRH (Gonadotropin-Releasing Hormone)**. This leads to decreased secretion of FSH and LH from the anterior pituitary (hypogonadotropic hypogonadism). The lack of LH/FSH prevents follicular development and the estrogen surge, resulting in anovulation and secondary amenorrhea. * **Galactorrhea (Option C):** Prolactin directly stimulates the mammary epithelial cells to produce milk. Galactorrhea is a classic clinical manifestation of hyperprolactinemia in both females and, occasionally, males. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most common cause:** Physiological (Pregnancy/Lactation) is the most common; Pathological is most commonly a **Prolactinoma** (Microadenoma <10mm; Macroadenoma >10mm). 2. **Drug-induced:** Dopamine antagonists (e.g., Metoclopramide, Haloperidol, Reserpine) cause hyperprolactinemia because dopamine is the primary **Prolactin-Inhibiting Factor (PIF)**. 3. **Treatment of choice:** Dopamine agonists like **Cabergoline** (preferred due to better efficacy/side effect profile) or Bromocriptine. 4. **Hook Effect:** In cases of extremely high prolactin (giant adenomas), lab tests may show falsely low levels; a dilution test is required for diagnosis.

Question 132: At what gestational age is the weight of the placenta and fetus approximately equal?

A. 14 weeks
B. 15 weeks
C. 17 weeks (Correct Answer)
D. 21 weeks

Explanation: **Explanation:** The relationship between fetal weight and placental weight changes dynamically throughout pregnancy. This is a high-yield concept in obstetric physiology, reflecting the shifting metabolic demands of the developing fetus. **1. Why 17 weeks is correct:** In the early second trimester, the placenta grows rapidly to establish the nutritional infrastructure required for the fetus. At approximately **17 weeks of gestation**, the growth curves of the fetus and the placenta intersect, and their weights are **nearly equal** (roughly 150–180 grams each). Prior to this point, the placenta is actually heavier than the fetus; after this point, fetal weight gain accelerates significantly, eventually far surpassing the placental weight. **2. Analysis of incorrect options:** * **14 & 15 weeks:** At these stages, the **placenta is heavier than the fetus**. The placenta must develop its vascular architecture before it can support rapid fetal mass accumulation. * **21 weeks:** By this stage, the fetus has entered a period of rapid growth. The fetus is now significantly heavier than the placenta. By term (40 weeks), the ratio of fetal weight to placental weight is approximately **6:1**. **3. High-Yield Clinical Pearls for NEET-PG:** * **Fetal-Placental Weight Ratio:** At term, the average placenta weighs about 500g, while the fetus weighs about 3000–3500g. * **Placental Growth:** The placenta continues to grow in thickness and circumference until near term, but its relative efficiency increases to meet fetal demands. * **Clinical Significance:** An abnormally large placenta (Placentomegaly) relative to fetal weight is seen in conditions like maternal diabetes, fetal hydrops, and syphilis. Conversely, a small placenta is associated with IUGR and preeclampsia.

Question 133: What is the karyotype in testicular feminization syndrome?

A. XX
B. XY (Correct Answer)
C. XXY
D. XXXY

Explanation: **Explanation:** **Testicular Feminization Syndrome**, now more commonly known as **Complete Androgen Insensitivity Syndrome (CAIS)**, is a condition where an individual is genetically male but phenotypically female. 1. **Why XY is Correct:** The underlying pathophysiology is a mutation in the **Androgen Receptor (AR) gene** located on the X chromosome. These individuals have a normal male genotype (**46, XY**) and functional testes (usually intra-abdominal) that produce normal or elevated male levels of testosterone. However, because the target tissues are completely unresponsive to androgens, the external genitalia develop along female lines. Anti-Müllerian Hormone (AMH) is still produced by the Sertoli cells, leading to the regression of internal female structures (uterus, fallopian tubes, and upper vagina). 2. **Why Other Options are Incorrect:** * **XX:** This is a normal female karyotype. In cases of primary amenorrhea with an XX karyotype, one would consider Müllerian Agenesis (MRKH), where ovaries are present but the uterus is absent. * **XXY:** This is **Klinefelter Syndrome**. These individuals have a male phenotype, small firm testes, and infertility, but they do not present with female external genitalia. * **XXXY:** This is a variant of Klinefelter Syndrome with more severe cognitive and physical manifestations, but the phenotype remains male. **High-Yield Clinical Pearls for NEET-PG:** * **Phenotype:** Tall stature, well-developed breasts (due to peripheral conversion of testosterone to estrogen), but **absent or scanty axillary and pubic hair** (a key diagnostic clue). * **Vagina:** Presents as a "blind-ending pouch" (short vagina). * **Management:** Gonadectomy is performed **after puberty** (to allow natural breast development) to prevent the risk of gonadoblastoma/dysgerminoma. * **Differential Diagnosis:** In **MRKH (XX)**, pubic/axillary hair is normal; in **CAIS (XY)**, it is absent.

Question 134: What fasting blood sugar level is considered diagnostic for gestational diabetes mellitus?

A. 100 mg/dl (Correct Answer)
B. 150 mg/dl
C. 175 mg/dl
D. 200 mg/dl

Explanation: **Explanation:** The diagnosis of Gestational Diabetes Mellitus (GDM) in India follows the **DIPSI (Diabetes in Pregnancy Study Group India)** guidelines, which have been adopted by the Ministry of Health and Family Welfare (MoHFW). Under these guidelines, a single-step 75g Oral Glucose Tolerance Test (OGTT) is used. **Why Option A is correct:** According to the DIPSI/WHO criteria, GDM is diagnosed if the plasma glucose level is **≥140 mg/dl** two hours after a 75g oral glucose load. However, for **fasting** plasma glucose levels, the threshold is lower. While DIPSI focuses on the non-fasting 2-hour value for screening ease, the standard diagnostic threshold for fasting blood sugar (FBS) in pregnancy is **≥92 mg/dl** (IADPSG criteria). In the context of this specific question and standard Indian medical examinations, **100 mg/dl** is the closest clinical cutoff used to indicate impaired fasting glucose or diagnostic GDM, as any value above 92–95 mg/dl is considered pathological in pregnancy. **Why the other options are incorrect:** * **Options B, C, and D (150, 175, 200 mg/dl):** These values are significantly higher than the physiological fasting limits. A fasting value of 126 mg/dl or higher actually suggests **Overt (Pre-gestational) Diabetes** rather than GDM. Values like 200 mg/dl are typically associated with random blood sugar thresholds for symptomatic diabetes. **High-Yield Clinical Pearls for NEET-PG:** * **DIPSI Criterion:** 75g glucose load given irrespective of the last meal. Diagnosis: 2-hour post-load value **≥140 mg/dl**. * **IADPSG/WHO Criteria:** Fasting ≥92 mg/dl; 1-hr ≥180 mg/dl; 2-hr ≥153 mg/dl (Only one abnormal value is needed). * **Best Time to Screen:** 24–28 weeks of gestation. * **First-line Management:** Medical Nutrition Therapy (MNT) for 2 weeks; if targets aren't met, Insulin is the drug of choice (Metformin is the oral alternative).

Question 135: How is gestational diabetes diagnosed?

A. Glucose tolerance test (GTT) (Correct Answer)
B. Random blood sugar
C. Fasting and postprandial blood sugar
D. 24-hour blood glucose profile

Explanation: **Explanation:** The diagnosis of Gestational Diabetes Mellitus (GDM) relies on the **Glucose Tolerance Test (GTT)**, which assesses the body's ability to handle a specific glucose load during the insulin-resistant state of pregnancy. According to the **DIPSI (Diabetes in Pregnancy Study Group India)** guidelines—the gold standard for NEET-PG—a single-step 75g Oral GTT is used. A plasma glucose level of **≥140 mg/dL** after 2 hours is diagnostic of GDM, regardless of the fasting state. **Why other options are incorrect:** * **Random Blood Sugar (RBS):** This is a screening tool for overt diabetes but lacks the sensitivity and standardization required to diagnose GDM, as it does not account for the timing of the last meal. * **Fasting and Postprandial (FBS/PPBS):** While used to monitor pre-existing (pre-gestational) diabetes or to manage GDM once diagnosed, they are not the primary diagnostic criteria for GDM screening. * **24-hour Blood Glucose Profile:** This involves multiple pricks throughout the day and is used for fine-tuning insulin therapy in hospitalized patients; it is too cumbersome and unnecessary for initial diagnosis. **High-Yield Clinical Pearls for NEET-PG:** * **Screening Timing:** Ideally performed at **24–28 weeks** of gestation. * **DIPSI Criteria:** 75g glucose is given irrespective of the last meal. If 2-hour value is ≥140 mg/dL, it is GDM. * **IADPSG/WHO Criteria:** Requires a 75g GTT in a **fasting state**. Diagnosis is made if any one value is met: Fasting ≥92 mg/dL, 1-hr ≥180 mg/dL, or 2-hr ≥153 mg/dL. * **HbA1c:** Not used for diagnosing GDM, but useful for identifying "Overt Diabetes" (pre-existing) if ≥6.5% in the first trimester.

Question 136: Maximum cardiac output in pregnancy occurs at which gestational age?

A. 20 weeks
B. 24 weeks
C. 26 weeks
D. 28 weeks (Correct Answer)

Explanation: **Explanation:** The correct answer is **28 weeks**. Cardiac output (CO) begins to increase as early as 5 weeks of gestation due to a combination of increased stroke volume and heart rate. It rises progressively throughout the second trimester, reaching its peak between **28 and 32 weeks** of gestation. At this point, the cardiac output is approximately 30–50% higher than in the non-pregnant state. This increase is a physiological adaptation to meet the metabolic demands of the growing fetus and the placenta. **Analysis of Options:** * **A, B, and C (20, 24, and 26 weeks):** While cardiac output is steadily increasing during these weeks, it has not yet reached its maximum plateau. These options represent the "rising phase" of the hemodynamic curve. * **D (28 weeks):** This marks the beginning of the peak window (28–32 weeks). In the context of NEET-PG, if a single value is required, 28 weeks is the traditionally accepted milestone for the maximum increase in resting cardiac output. **High-Yield Clinical Pearls for NEET-PG:** 1. **The "Real" Maximum:** While 28–32 weeks is the peak during *gestation*, the absolute maximum cardiac output occurs **immediately postpartum** (due to "autotransfusion" from the contracted uterus and relief of IVC compression). 2. **Labor:** Cardiac output increases further during labor (by ~40% over late pregnancy levels) due to pain, anxiety, and uterine contractions. 3. **Clinical Significance:** Patients with underlying heart disease (e.g., Mitral Stenosis) are at the highest risk of **heart failure** during two specific periods: at **28–32 weeks** (peak volume) and **immediately after delivery**. 4. **Positioning:** In late pregnancy, cardiac output is lower in the supine position due to **Aortocaval compression**; it is highest in the left lateral recumbent position.

Question 137: All of the following statements regarding fetal skeletal mineralization are true EXCEPT:

A. Approximately 30g of calcium is needed, especially during the 3rd trimester.
B. Calcium required by the fetus is only 10% of the maternal skeletal calcium. (Correct Answer)
C. The amount of calcium absorbed increases to 400mg/day in the third trimester.
D. Plasma parathyroid hormone (PTH) concentration decreases in the first trimester but increases progressively thereafter.

Explanation: This question tests your knowledge of maternal-fetal calcium homeostasis. ### **Explanation of the Correct Answer (Option B)** The statement in Option B is incorrect because the total fetal requirement for calcium is approximately **25–30g**, which represents only about **2–3%** of the total maternal skeletal calcium (not 10%). The maternal skeleton is highly efficient at preserving its integrity; most of the calcium required for the fetus is provided by increased maternal intestinal absorption rather than significant bone resorption. ### **Analysis of Other Options** * **Option A:** True. A full-term fetus contains ~30g of calcium. About **80%** of this is deposited during the **third trimester**, when fetal skeletal mineralization is most rapid. * **Option C:** True. To meet the high fetal demand, maternal intestinal calcium absorption doubles by the 12th week of gestation. In the third trimester, the mother absorbs approximately **400 mg/day** of calcium. * **Option D:** True. Maternal plasma PTH levels typically drop in the first trimester (due to increased calcium absorption and high calcitonin) but rise progressively throughout the remainder of pregnancy to maintain maternal serum calcium levels despite the continuous fetal "drain." ### **High-Yield NEET-PG Pearls** * **Calcium Transfer:** Occurs via **active transport** across the placenta, mediated by PTH-related protein (PTHrP) produced in the placenta and fetal parathyroid glands. * **Fetal vs. Maternal Levels:** The fetus is relatively **hypercalcemic** compared to the mother to facilitate bone growth. * **Vitamin D:** Maternal 1,25-(OH)₂D₃ (Calcitriol) levels **double** during pregnancy, primarily driving the increased intestinal absorption of calcium. * **The "Physiological Hyperparathyroidism":** The progressive rise in PTH during the 2nd and 3rd trimesters is a compensatory mechanism to ensure adequate calcium availability for the fetus.

Question 138: A 20-week pregnant woman presents with newly diagnosed hypertension. You are concerned about potential fetal and placental compromise. Which of the following hormone measurements would be most informative for assessing fetal and placental health?

A. Urinary estriol and serum hCG (Correct Answer)
B. Serum progesterone and prolactin
C. Serum LH and hPL
D. Urinary estriol and serum progesterone

Explanation: **Explanation:** The assessment of the feto-placental unit relies on hormones that require the coordinated metabolic activity of both the fetus and the placenta. **Why Option A is Correct:** * **Urinary Estriol ($E_3$):** Estriol is the primary estrogen of pregnancy. Its synthesis requires a functional fetal adrenal gland (to produce DHEAS), a functional fetal liver (for 16-$\alpha$ hydroxylation), and a functional placenta (to aromatize it into estriol). Therefore, a drop in maternal urinary estriol is a sensitive indicator of **fetal distress** or placental compromise. * **Serum hCG:** Produced by the syncytiotrophoblast, hCG levels reflect **placental health** and viability. In the second trimester, abnormal levels can be associated with placental dysfunction or chromosomal anomalies. **Analysis of Incorrect Options:** * **Option B:** Progesterone is primarily a marker of the corpus luteum (early) and then the placenta; it does not require fetal precursors. Prolactin is secreted by the maternal pituitary and the decidua, making it an unreliable marker for fetal health. * **Option C:** LH is suppressed during pregnancy due to high estrogen/progesterone. While hPL (Human Placental Lactogen) reflects placental mass, it is less specific for acute fetal well-being than estriol. * **Option D:** While estriol is useful, progesterone only reflects placental function, not the integrated feto-placental unit. **NEET-PG High-Yield Pearls:** * **Estriol ($E_3$)** is the "Estrogen of Pregnancy." A 40%–50% decrease in serial measurements is clinically significant for fetal jeopardy. * **DHEAS** from the fetal adrenal is the mandatory precursor for placental estriol. * **Low Estriol** is also seen in: Fetal anencephaly (lack of ACTH), placental sulfatase deficiency, and maternal corticosteroid use. * **hCG** peaks at **8–10 weeks** (approx. 100,000 mIU/mL) and then declines to a plateau.

Question 139: Gestational diabetes mellitus is usually diagnosed at which point during pregnancy?

A. First trimester
B. Second trimester and early third trimester (Correct Answer)
C. At the time of delivery
D. Perinatal period

Explanation: **Explanation:** **1. Why the Correct Answer is Right:** Gestational Diabetes Mellitus (GDM) is primarily a disease of **insulin resistance** triggered by placental hormones. During the **second trimester (around 24–28 weeks)**, the placenta grows significantly and increases the secretion of diabetogenic hormones, most notably **Human Placental Lactogen (hPL)**, along with cortisol, growth hormone, and progesterone. These hormones act as insulin antagonists to ensure a steady glucose supply to the fetus. In a normal pregnancy, the pancreas compensates by increasing insulin production; however, in GDM, this compensation fails, leading to hyperglycemia. Therefore, universal screening is standardly performed between **24 and 28 weeks of gestation.** **2. Why the Other Options are Wrong:** * **Option A:** Hyperglycemia detected in the first trimester is usually classified as **Overt (Pre-gestational) Diabetes**, representing undiagnosed Type 2 DM that existed prior to pregnancy, as the insulin-antagonistic effect of the placenta is not yet significant. * **Option C & D:** Diagnosing GDM at delivery or the perinatal period is too late. The goal of screening is to prevent complications like macrosomia, shoulder dystocia, and neonatal hypoglycemia by managing blood sugar levels during the late second and third trimesters. **3. Clinical Pearls for NEET-PG:** * **Gold Standard Screening:** The **DIPSI (Diabetes in Pregnancy Study Group India)** guidelines recommend a single-step 75g Oral Glucose Tolerance Test (OGTT). A 2-hour plasma glucose value **≥140 mg/dL** is diagnostic of GDM. * **High-Risk Patients:** If a woman has risk factors (obesity, previous GDM, family history), screening should be done at the **first prenatal visit**. If negative, it must be repeated at 24–28 weeks. * **Most Diabetogenic Hormone:** Human Placental Lactogen (hPL).

Question 140: Clomiphene acts to induce ovulation by which mechanisms?

A. Diminishing ER-mediated negative feedback at the pituitary (Correct Answer)
B. Increasing the action of ER alpha in the ovary
C. Increasing the action of ER alpha in the hypothalamus
D. Increasing the amount of ER alpha

Explanation: **Explanation:** **Mechanism of Action:** Clomiphene Citrate (CC) is a Selective Estrogen Receptor Modulator (SERM). Its primary mechanism for inducing ovulation is its **anti-estrogenic effect** on the hypothalamic-pituitary-ovarian axis. The correct answer is **A** because Clomiphene binds to estrogen receptors (ER) in the **pituitary and hypothalamus**, occupying them for extended periods. This prevents endogenous estrogen from exerting its normal **negative feedback**. The brain "perceives" low estrogen levels, leading to a compensatory increase in the pulse frequency of **GnRH** and a subsequent rise in **FSH and LH** from the anterior pituitary. This "FSH window" expansion stimulates follicular development in the ovary. **Why other options are incorrect:** * **B & C:** Clomiphene acts as an **antagonist** (not an agonist) at the level of the hypothalamus and pituitary. It decreases/blocks the action of ER alpha rather than increasing it. * **D:** Clomiphene works by **depleting** or downregulating the total number of available estrogen receptors over time, not by increasing the amount of ER alpha. **High-Yield Clinical Pearls for NEET-PG:** * **First-line drug:** Historically the first-line for WHO Group II ovulation induction (PCOS), though **Letrozole** (Aromatase Inhibitor) is now preferred due to higher live birth rates. * **Anti-estrogenic side effects:** It has an undesirable thinning effect on the **endometrium** and thickens the **cervical mucus**, which may hinder implantation/sperm penetration. * **Risk:** Associated with a 5–10% risk of **multiple pregnancies** (primarily twins) and Ovarian Hyperstimulation Syndrome (OHSS). * **Administration:** Usually started on Day 2, 3, 4, or 5 of the menstrual cycle for 5 days.

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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