Endocrinology of Pregnancy Practice Questions

Q: Basal metabolic rate (BMR) changes by what percentage during pregnancy?

Increases by 25%. **Explanation:** The Basal Metabolic Rate (BMR) increases significantly during pregnancy, primarily to meet the increased oxygen demands of the growing fetus, the placenta, and the expansion of maternal tissues (such as the uterus and breasts). **Why Option A is Correct:** During a normal singleton pregnancy, the BMR increases by approximately **20% to 25%**. This rise is most pronounced during the third trimester. The physiological drivers include: * **Increased Cardiac Work:** The maternal heart works harder to maintain increased cardiac output. * **Respiratory Effort:** Increased work of breathing to sustain higher oxygen consumption. * **Fetal-Placental Unit:** The metabolic activity of the fetus and placenta accounts for a significant portion of the total energy expenditure. **Why Other Options are Incorrect:** * **Option B & D:** Pregnancy is a hypermetabolic state; therefore, any decrease in BMR is physiologically incorrect. * **Option C:** An increase of 50% is excessive for a singleton pregnancy. While BMR can rise further in multifetal gestations (e.g., twins), the standard physiological benchmark for medical exams is 25%. **NEET-PG High-Yield Pearls:** 1. **Total Weight Gain:** The average weight gain in a healthy pregnancy (BMI 18.5–24.9) is **11 kg to 16 kg**. 2. **Caloric Requirement:** To support the increased BMR, an additional **300–350 kcal/day** is required during the second and third trimesters. 3. **Thyroid Function:** Although BMR increases, a healthy pregnant woman remains **euthyroid**. Total T3 and T4 levels rise due to increased Thyroid Binding Globulin (TBG), but Free T3 and T4 remain within normal limits. 4. **Insulin Resistance:** Pregnancy is a "diabetogenic state" due to Human Placental Lactogen (hPL), which ensures a steady glucose supply to the fetus.

Q: What are the changes in the respiratory system during pregnancy?

Residual volume is decreased. **Explanation:** Respiratory changes in pregnancy are primarily driven by the mechanical effects of the enlarging uterus and the stimulatory effects of progesterone. **Why the correct answer (D) is right:** As the uterus enlarges, it elevates the diaphragm by approximately 4 cm. This upward displacement reduces the space available in the lungs at the end of expiration. Consequently, the **Residual Volume (RV)** and the **Functional Residual Capacity (FC)** decrease by approximately 20%. Despite the elevation, diaphragmatic excursion actually increases to maintain ventilation. **Analysis of incorrect options:** * **A. Vital capacity is increased:** Vital capacity (VC) remains **unchanged** or may show a very slight increase. While the diaphragm rises, there is a compensatory increase in the transverse and anteroposterior diameters of the chest wall. * **B. Subcostal angle remains unchanged:** The subcostal angle **increases** significantly (from about 68° to 103°) due to the hormonal relaxation of rib ligaments and the mechanical pressure of the uterus, widening the thoracic cage. * **C. Tidal volume remains unaltered:** Tidal volume (TV) **increases** by approximately 40%. Progesterone acts as a direct respiratory stimulant, increasing the sensitivity of the respiratory center to CO2, leading to deeper breaths (hyperventilation of pregnancy). **High-Yield NEET-PG Pearls:** * **Most common change:** Increase in Tidal Volume. * **Parameters that Decrease:** Residual Volume (RV), Functional Residual Capacity (FRC), Total Lung Capacity (TLC), and Expiratory Reserve Volume (ERV). * **Parameters that Increase:** Tidal Volume (TV), Minute Ventilation, and Inspiratory Capacity. * **Acid-Base Status:** Pregnancy is a state of **compensated respiratory alkalosis** (decreased $PCO_2$ to facilitate CO2 transfer from the fetus).

Q: The corpus luteum supports the endometrium in pregnancy until which gestational period?

6-10 weeks. **Explanation:** The maintenance of early pregnancy depends on the secretion of progesterone by the **corpus luteum of pregnancy**. This process is driven by Human Chorionic Gonadotropin (hCG), which rescues the corpus luteum from regression. 1. **Why Option A is Correct:** The transition of progesterone production from the corpus luteum to the placenta is known as the **Luteal-Placental Shift**. This shift begins around the 6th-7th week and is typically complete by the **10th week** of gestation. While the corpus luteum persists throughout pregnancy, its functional necessity for endometrial support ends once the trophoblastic cells (placenta) produce sufficient progesterone to maintain the pregnancy independently. 2. **Why Other Options are Incorrect:** * **Option B (12-24 weeks):** By 12 weeks, the placenta is the primary source of progesterone. Surgical removal of the corpus luteum after 10 weeks usually does not result in miscarriage. * **Options C & D (36-42 weeks):** These represent late third trimester and post-term periods. The corpus luteum is functionally redundant for hormonal support long before this stage. **NEET-PG High-Yield Pearls:** * **Luteectomy:** If the corpus luteum is surgically removed before **8 weeks**, exogenous progesterone supplementation is mandatory to prevent abortion. Between 8–10 weeks, it is controversial but often supplemented. After 10 weeks, it is generally unnecessary. * **hCG Peak:** hCG levels peak at approximately **8–10 weeks**, coinciding with the maximum stimulation of the corpus luteum before the placental shift is finalized. * **Source of Progesterone:** 0–6 weeks (Corpus Luteum); 7–10 weeks (Transition); >10 weeks (Placenta).

Q: A 32-year-old female with diabetes presents at 6 weeks of amenorrhea. She is not on any treatment. What is the first step in her management?

Perform HbA1c test. **Explanation:** The correct answer is **C. Perform HbA1c test.** **1. Why HbA1c is the first step:** In a patient with pre-existing diabetes (or suspected overt diabetes) presenting in the first trimester, the primary concern is the risk of **congenital malformations**. HbA1c reflects glycemic control over the preceding 8–12 weeks, covering the critical period of organogenesis. A high HbA1c level (>7%) is strongly associated with an increased risk of anomalies (e.g., Sacral agenesis, VSD). It serves as a baseline to assess the risk of teratogenicity and guides the intensity of management. **2. Why other options are incorrect:** * **A & B (Insulin/Diet):** While glycemic control is essential, management cannot be initiated without first assessing the severity of the baseline glycemic status and the risk to the fetus. HbA1c provides the necessary prognostic information before deciding on the therapeutic regimen. * **D (Postprandial glucose):** While daily monitoring is vital for ongoing management, a single point-in-time glucose test does not provide information about the glycemic control during the early weeks of pregnancy (organogenesis), which is the priority at 6 weeks gestation. **3. NEET-PG High-Yield Pearls:** * **Most common malformation** in infants of diabetic mothers: **VSD** (Ventricular Septal Defect). * **Most specific malformation:** **Caudal Regression Syndrome** (Sacral Agenesis). * **Target HbA1c:** Ideally, HbA1c should be **<6.5%** (or <6% if achievable without hypoglycemia) to minimize the risk of malformations. * **Overt Diabetes vs. GDM:** If fasting plasma glucose is ≥126 mg/dL or HbA1c is ≥6.5% at the first prenatal visit, it is classified as **Overt Diabetes**, not Gestational Diabetes Mellitus (GDM).

Q: Which of the following is a feature of diabetes mellitus in pregnancy?

Hydramnios. **Explanation:** **1. Why Hydramnios is Correct:** Polyhydramnios (Hydramnios) is a classic complication of maternal diabetes. The underlying mechanism is **fetal osmotic diuresis**. High maternal blood glucose levels cross the placenta, leading to **fetal hyperglycemia**. This stimulates the fetal kidneys to produce excessive urine (polyuria) to clear the glucose load. Since fetal urine is the primary source of amniotic fluid in the second and third trimesters, this results in an increased amniotic fluid index (AFI). **2. Why the Other Options are Incorrect:** * **Postdatism (Option A):** Diabetes is actually associated with an increased risk of **preterm labor** (due to polyhydramnios or preeclampsia) and is an indication for **planned induction of labor** (usually by 39 weeks). Post-term pregnancy is avoided to prevent sudden intrauterine fetal death (IUFD) and macrosomia-related complications. * **Neonatal Hyperglycemia (Option C):** This is a common distractor. While the fetus is hyperglycemic *in utero*, the neonate suffers from **Neonatal Hypoglycemia**. After birth, the maternal glucose supply is cut off, but the neonate’s pancreas remains in a state of hyperinsulinemia (due to chronic stimulation in utero), causing a rapid drop in blood sugar levels. **3. NEET-PG High-Yield Clinical Pearls:** * **Most common fetal anomaly in DM:** Cardiac anomalies (specifically **Ventricular Septal Defect**). * **Most specific fetal anomaly in DM:** **Caudal Regression Syndrome** (Sacral agenesis). * **Macrosomia:** Defined as birth weight >4000g or 4500g; characterized by increased shoulder-to-head circumference ratio, increasing the risk of **shoulder dystocia**. * **Target HbA1c:** Ideally <6% preconception to minimize the risk of congenital malformations.

Q: Which of the following hormones is NOT secreted by the placenta?

Insulin. **Explanation:** The placenta acts as a sophisticated transient endocrine organ, producing a wide array of protein and steroid hormones to maintain pregnancy. **Why Insulin is the Correct Answer:** Insulin is a peptide hormone produced exclusively by the **beta cells of the Islets of Langerhans in the pancreas**. While the placenta produces hormones that significantly influence maternal glucose metabolism (like Human Placental Lactogen/hPL), it does **not** synthesize insulin. Furthermore, maternal insulin does not cross the placental barrier; the fetus relies entirely on its own pancreatic production for glycemic control. **Analysis of Incorrect Options:** * **hCG (Human Chorionic Gonadotropin):** This is the first hormone secreted by the syncytiotrophoblast. It is essential for maintaining the corpus luteum in early pregnancy. * **TRH (Thyrotropin-Releasing Hormone):** The placenta produces various hypothalamic-like releasing hormones, including TRH, GnRH, and CRH. These function locally to regulate placental hormone secretion. * **ACTH (Adrenocorticotropic Hormone):** The placenta synthesizes POMC-derived peptides, including ACTH. Unlike pituitary ACTH, placental ACTH is relatively resistant to feedback suppression by glucocorticoids. **High-Yield Clinical Pearls for NEET-PG:** * **hPL (Human Placental Lactogen):** Also known as Human Chorionic Somatomammotropin (hCS), it is the primary hormone responsible for the **diabetogenic state** of pregnancy (insulin resistance). * **Progesterone:** Often called the "hormone of pregnancy," the placenta takes over its production from the corpus luteum at approximately **7–9 weeks** (Luteo-placental shift). * **Estriol (E3):** The dominant estrogen in pregnancy; its synthesis requires the **fetal adrenal gland** (DHEAS) and **fetal liver** (16-alpha-hydroxylation), making it a marker of feto-placental well-being.

Question 1

Basal metabolic rate (BMR) changes by what percentage during pregnancy?

Accepted Answer

Increases by 25%

Answer

Decreases by 25%

Answer

Increases by 50%

Answer

Decreases by 50%

Question 2

What are the changes in the respiratory system during pregnancy?

Accepted Answer

Residual volume is decreased

Answer

Vital capacity is increased

Answer

Subcostal angle remains unchanged

Answer

Tidal volume remains unaltered

Question 3

Delayed puberty is seen in which of the following conditions?

Accepted Answer

Chronic disease

Answer

Hypothyroidism

Answer

Turner's syndrome

Answer

Malabsorption syndrome

Question 4

The corpus luteum supports the endometrium in pregnancy until which gestational period?

Accepted Answer

6-10 weeks

Answer

12-24 weeks

Answer

36 weeks

Answer

42 weeks

Question 5

A 16-year-old female presents with primary amenorrhea. Examination shows a short, blind vagina and an absent uterus. What is the next investigation of choice?

Accepted Answer

Karyotyping

Answer

Intravenous pyelogram (IVP)

Answer

Gonadotrophin levels

Answer

Serum prolactin

Question 6

A female patient presents with normal breast development but scanty pubic hair. What condition is she likely suffering from?

Accepted Answer

Testicular feminization syndrome

Answer

Turner syndrome

Answer

Mullerian agenesis

Answer

Gonadal dysgenesis

Question 7

What is the recommended treatment for gestational diabetes mellitus?

Accepted Answer

Insulin

Answer

Glibenclamide

Answer

Chlorpropamide

Answer

Glipizide

Question 8

A 32-year-old female with diabetes presents at 6 weeks of amenorrhea. She is not on any treatment. What is the first step in her management?

Accepted Answer

Perform HbA1c test

Answer

Start insulin therapy

Answer

Initiate dietary modifications

Answer

Perform postprandial blood glucose tests

Question 9

Which of the following is a feature of diabetes mellitus in pregnancy?

Accepted Answer

Hydramnios

Answer

Postdatism

Answer

Neonatal hyperglycemia

Answer

All of the above

Question 10

Which of the following hormones is NOT secreted by the placenta?

Accepted Answer

Insulin

Answer

hCG

Answer

TRH

Answer

ACTH

Endocrinology of Pregnancy — MCQs

Endocrinology of Pregnancy — MCQs

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