Maternal-Fetal Medicine Practice Questions

Q: What is the most common heart disease associated with pregnancy?

Mitral stenosis. **Explanation:** **1. Why Mitral Stenosis (MS) is the Correct Answer:** Rheumatic Heart Disease (RHD) remains the most common cause of organic heart disease in pregnancy, particularly in developing countries like India. Among RHD lesions, **Mitral Stenosis** is the most frequent (occurring in approximately 70-90% of cases). Pregnancy poses a significant challenge to MS because the physiological increase in heart rate and blood volume shortens diastolic filling time, leading to increased left atrial pressure. This significantly raises the risk of pulmonary edema and atrial fibrillation, especially during the second trimester and labor. **2. Analysis of Incorrect Options:** * **B. Mitral Regurgitation:** While common in RHD, it is less frequent than MS. Interestingly, MR is often better tolerated during pregnancy because the physiological decrease in systemic vascular resistance (SVR) reduces the regurgitant fraction. * **C. Patent Ductus Arteriosus (PDA):** This is a common congenital heart disease (CHD). While CHD is becoming more prevalent in pregnancy due to improved surgical outcomes, RHD (specifically MS) still outnumbers it in the overall pregnant population in the Indian context. * **D. Tetralogy of Fallot (TOF):** This is the most common *cyanotic* congenital heart disease. However, it is much rarer in pregnancy compared to valvular lesions like MS. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common heart disease in pregnancy:** Rheumatic Heart Disease (RHD). * **Most common valvular lesion:** Mitral Stenosis. * **Most common Congenital Heart Disease (CHD) in pregnancy:** Atrial Septal Defect (ASD). * **Most common cause of maternal death in heart disease:** Heart failure/Pulmonary edema. * **Critical periods for heart failure:** 28–32 weeks of gestation, during labor, and the immediate postpartum period (due to "autotransfusion" from the uterus).

Q: Clinical signs of hydramnios can be demonstrated when amniotic fluid collection is more than:

2 liters. **Explanation:** **1. Understanding the Correct Answer (B):** Hydramnios (Polyhydramnios) is defined pathologically as an amniotic fluid volume exceeding **2,000 ml (2 liters)**. While the normal volume at term is approximately 600–800 ml, clinical signs such as an overdistended abdomen, "fluid thrill," and difficulty palpating fetal parts typically manifest only when the volume crosses the **2-liter threshold**. In clinical practice, this is often diagnosed via ultrasound using an Amniotic Fluid Index (AFI) ≥ 25 cm or a Single Deepest Pocket (SDP) ≥ 8 cm. **2. Analysis of Incorrect Options:** * **A (1 liter):** While 1 liter is above the average volume at term, it is still within the physiological upper limit (up to 1.5 liters can be normal in some pregnancies). It does not meet the diagnostic criteria for polyhydramnios. * **C & D (3 and 4 liters):** These volumes represent severe polyhydramnios. While clinical signs are certainly present at these levels, the question asks for the minimum threshold at which hydramnios can be demonstrated, which is 2 liters. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most Common Cause:** Idiopathic (approx. 50–60%). * **Maternal Cause:** Diabetes Mellitus is the most common maternal association. * **Fetal Causes:** Tracheoesophageal fistula, anencephaly (lack of swallowing/antidiuretic hormone), and fetal hydrops. * **Complications:** Preterm labor (due to uterine overdistension), Cord Prolapse (due to sudden rupture of membranes), and Postpartum Hemorrhage (PPH) due to uterine atony. * **Management:** Therapeutic amniocentesis (amnionreduction) or Indomethacin (decreases fetal urine output, but used with caution due to risk of premature closure of ductus arteriosus).

Q: Which of the following complications is NOT caused by malaria in pregnancy?

HELLP syndrome. **Explanation:** Malaria in pregnancy, particularly when caused by *Plasmodium falciparum*, leads to significant maternal and fetal morbidity due to **placental sequestration**. In this process, parasitized erythrocytes express ligands (like VAR2CSA) that bind to chondroitin sulfate A in the placenta. This triggers an inflammatory response, leading to placental insufficiency and vascular damage. **Why HELLP Syndrome is the Correct Answer:** HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets) is a severe manifestation of the **preeclampsia spectrum**, primarily driven by abnormal trophoblastic invasion and generalized endothelial dysfunction. While malaria can cause hemolysis and thrombocytopenia, it does not etiologically cause the specific multi-organ triad of HELLP syndrome. **Why the other options are incorrect:** * **IUGR (Option B):** Placental sequestration of parasites leads to chronic placental insufficiency and nutrient deprivation, making IUGR one of the most common complications of malaria in pregnancy. * **IUD (Option C):** Severe maternal anemia, high-grade fever (hyperpyrexia), and acute placental damage can lead to fetal hypoxia and subsequent intrauterine death. * **Preterm Delivery (Option D):** The systemic inflammatory cytokine response (TNF-α, IL-1) triggered by malaria can stimulate uterine contractions, leading to spontaneous preterm labor. **High-Yield Clinical Pearls for NEET-PG:** * **Most common complication:** Maternal anemia and Low Birth Weight (LBW). * **Drug of Choice:** According to WHO/National guidelines, **Artesunate-based Combination Therapy (ACT)** is now recommended for uncomplicated malaria in all trimesters. **Quinine** is an alternative in the first trimester if ACT is unavailable. * **Prophylaxis:** Intermittent Preventive Treatment (IPTp) with Sulfadoxine-Pyrimethamine is recommended in endemic areas.

Q: Which among the following is an early sign of magnesium toxicity?

Depression of deep tendon reflexes. Magnesium sulfate ($MgSO_4$) is the drug of choice for seizure prophylaxis in pre-eclampsia and control in eclampsia. However, it has a narrow therapeutic index, making the monitoring of toxicity critical for NEET-PG. **Explanation of the Correct Answer:** **Depression or loss of Deep Tendon Reflexes (DTRs)**, specifically the patellar reflex, is the **earliest clinical sign** of magnesium toxicity. This occurs at serum magnesium levels of **7–10 mEq/L** (Normal therapeutic range is 4–7 mEq/L). Magnesium acts as a calcium antagonist at the neuromuscular junction, inhibiting acetylcholine release; since the neuromuscular junction of the stretch reflex is highly sensitive, DTRs are lost before other systems are affected. **Analysis of Incorrect Options:** * **B. Respiratory Depression:** This is a late sign of toxicity, typically occurring at levels of **11–15 mEq/L**. It results from paralysis of the respiratory muscles. * **C. Cardiac Arrest:** This is a terminal event occurring at very high levels, usually **>15–20 mEq/L**, due to the direct effect of magnesium on cardiac conduction. * **D. Decreased Urine Output:** This is a **precursor** to toxicity rather than a sign of it. Since magnesium is excreted almost exclusively by the kidneys, oliguria leads to magnesium accumulation, which then causes toxicity. **High-Yield Clinical Pearls for NEET-PG:** 1. **Monitoring Parameters:** Before every dose of $MgSO_4$, check: (1) Presence of Patellar reflex, (2) Respiratory rate (>12-14/min), and (3) Urine output (>30 ml/hr or 100 ml/4hrs). 2. **Antidote:** 10 ml of **10% Calcium Gluconate** IV (administered slowly over 10 minutes). 3. **Therapeutic Range:** 4–7 mEq/L (or 4.8–8.4 mg/dL).

Q: What is TRUE regarding the findings of a single umbilical artery on examination of the umbilical cord?

More common in newborns of diabetic mothers. **Explanation:** A **Single Umbilical Artery (SUA)**, or the absence of one umbilical artery, is the most common umbilical cord anomaly. While the normal cord contains two arteries and one vein, SUA occurs due to either primary agenesis of one artery or the secondary atrophy of a previously normal vessel. **Why Option D is Correct:** Epidemiological studies have consistently shown that the incidence of SUA is significantly higher in specific high-risk groups. It is **3 to 4 times more common in newborns of diabetic mothers**. Other risk factors include maternal smoking, advanced maternal age (>35 years), and twin pregnancies. **Analysis of Incorrect Options:** * **Option A (Insignificant):** SUA is clinically significant. While it can be an isolated finding, it is a marker for potential underlying issues. Approximately 20–30% of fetuses with SUA have associated structural or chromosomal anomalies. * **Option B (Equal incidence in all races):** This is incorrect. SUA shows racial variation; it is significantly more common in **Caucasian** populations compared to African or Asian populations. * **Option C (No association with major malformation):** SUA is frequently associated with major malformations, most commonly involving the **genitourinary system** (e.g., renal agenesis), cardiovascular system (e.g., VSD), and gastrointestinal tract. It is also linked to chromosomal trisomies (especially Trisomy 18 and 13). **High-Yield Clinical Pearls for NEET-PG:** * **Most common associated anomaly:** Renal/Genitourinary malformations. * **Management:** If SUA is detected on ultrasound, a detailed **Level II anomaly scan** and **fetal echocardiography** are mandatory. * **Growth:** Fetuses with isolated SUA are at a higher risk for **Intrauterine Growth Restriction (IUGR)**; hence, serial growth scans are recommended. * **Side:** The **left** umbilical artery is more commonly absent than the right.

Q: In asymmetrical Intrauterine Growth Restriction (IUGR), which organ is typically spared from significant growth restriction?

Brain. ### Explanation **Correct Answer: D. Brain** **The Concept: The "Brain-Sparing Effect"** Asymmetrical Intrauterine Growth Restriction (IUGR) usually occurs in the late second or third trimester, often due to placental insufficiency (e.g., maternal hypertension or pre-eclampsia). When the fetus faces a chronic shortage of nutrients and oxygen, it undergoes a compensatory hemodynamic redistribution known as the **"Brain-Sparing Effect."** Blood flow is preferentially shunted toward vital organs—the **brain, heart, and adrenal glands**—at the expense of peripheral and abdominal organs. This ensures that head circumference remains relatively normal while the abdominal circumference lags, leading to the characteristic "asymmetrical" appearance (increased Head Circumference to Abdominal Circumference ratio). **Why the other options are incorrect:** * **C. Liver:** This is the organ most affected in asymmetrical IUGR. The decrease in fetal liver size (due to depleted glycogen stores) is the primary reason for the reduced abdominal circumference seen on ultrasound. * **A & B. Subcutaneous fat and Muscle:** These are non-vital tissues. During periods of nutrient deprivation, the fetus mobilizes fat stores and limits muscle development to conserve energy for the brain and heart. **High-Yield Clinical Pearls for NEET-PG:** * **Symmetrical IUGR:** Occurs early in pregnancy (hyperplastic phase). All organs, including the brain, are proportionately small. Common causes: Chromosomal anomalies, TORCH infections. * **Asymmetrical IUGR:** Occurs late (hypertrophic phase). Causes: Uteroplacental insufficiency. * **Ponderal Index:** This is low in asymmetrical IUGR but remains normal in symmetrical IUGR. * **Doppler Findings:** Brain-sparing is identified by **decreased resistance** in the Middle Cerebral Artery (MCA) and increased resistance in the Umbilical Artery.

Q: An obstetrician sees a pregnant patient who was exposed to rubella virus at eighteen weeks of pregnancy. She does not remember getting a rubella vaccination. What is the best immediate course of action?

Order a rubella antibody titer to determine immune status. **Explanation:** The management of rubella exposure in pregnancy depends on the mother’s immune status and the gestational age at exposure. **Why Option B is Correct:** The immediate priority is to determine if the mother is already immune. A **Rubella IgG antibody titer** should be ordered. If the patient is IgG positive, she is immune, and the fetus is at no risk. If she is IgG negative (susceptible), a second sample is taken 2–3 weeks later to check for seroconversion (IgM or rising IgG), which would indicate an acute infection. **Why Other Options are Incorrect:** * **Option A:** Termination is not indicated without confirming maternal infection and assessing fetal risk. Furthermore, the risk of **Congenital Rubella Syndrome (CRS)** decreases significantly after 16 weeks; exposure at 18 weeks carries a much lower risk (approx. 10–15%) compared to the first trimester. * **Option C:** This is factually incorrect. Rubella is most dangerous in the **first trimester** (up to 85% risk of CRS). While the risk decreases after 16 weeks, it does not become "not a problem" specifically after 30 weeks. * **Option D:** The rubella vaccine is a **Live Attenuated Vaccine (RA 27/3 strain)** and is strictly **contraindicated during pregnancy** due to the theoretical risk of fetal infection. **High-Yield Clinical Pearls for NEET-PG:** * **Gregg’s Triad (CRS):** Cataracts, Sensorineural hearing loss (most common), and Cardiac defects (PDA/Peripheral Pulmonary Artery Stenosis). * **Vaccination Timing:** If a woman is found to be non-immune during pregnancy, she should be vaccinated in the **immediate postpartum period**. She must avoid pregnancy for **28 days (1 month)** after vaccination. * **Diagnosis:** The presence of **Rubella IgM** in a newborn is diagnostic of congenital infection, as IgM does not cross the placenta.

Question 1

What is the most common heart disease associated with pregnancy?

Accepted Answer

Mitral stenosis

Answer

Mitral regurgitation

Answer

Patent ductus arteriosus

Answer

Tetralogy of Fallot

Question 2

Clinical signs of hydramnios can be demonstrated when amniotic fluid collection is more than:

Accepted Answer

2 liters

Answer

1 liter

Answer

3 liters

Answer

4 liters

Question 3

Which of the following complications is NOT caused by malaria in pregnancy?

Accepted Answer

HELLP syndrome

Answer

Intrauterine growth restriction (IUGR)

Answer

Intrauterine death (IUD)

Answer

Preterm delivery

Question 4

Which among the following is an early sign of magnesium toxicity?

Accepted Answer

Depression of deep tendon reflexes

Answer

Respiratory depression

Answer

Cardiac arrest

Answer

Decreased urine output

Question 5

What is TRUE regarding the findings of a single umbilical artery on examination of the umbilical cord?

Accepted Answer

More common in newborns of diabetic mothers

Answer

Insignificant

Answer

Equal in incidence in all races

Answer

No incidence of any association with major malformation of the fetus

Question 6

What is the most common type of heart disease encountered in pregnancy?

Accepted Answer

Mitral Stenosis (MS)

Answer

Atrial Septal Defect (ASD)

Answer

Ventricular Septal Defect (VSD)

Answer

Mitral Regurgitation (MR)

Question 7

In asymmetrical Intrauterine Growth Restriction (IUGR), which organ is typically spared from significant growth restriction?

Accepted Answer

Brain

Answer

Subcutaneous fat

Answer

Muscle

Answer

Liver

Question 8

In the Manning scoring system of biophysical profile for fetal monitoring, which parameter is not included?

Accepted Answer

Oxytocin challenge test

Answer

Fetal tone

Answer

Fetal gross body movements

Answer

Non-stress test

Question 9

Congenital anomalies are most severe in which of the following infections?

Accepted Answer

Rubella infection

Answer

Mumps

Answer

Cytomegalovirus (CMV)

Answer

Toxoplasma

Question 10

An obstetrician sees a pregnant patient who was exposed to rubella virus at eighteen weeks of pregnancy. She does not remember getting a rubella vaccination. What is the best immediate course of action?

Accepted Answer

Order a rubella antibody titer to determine immune status

Answer

Terminate the pregnancy

Answer

Reassure the patient because rubella is not a problem until after the thirtieth week

Answer

Administer rubella vaccine

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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