Maternal-Fetal Medicine Practice Questions

Q: A 32-year-old woman, 6 weeks pregnant, with a history of a previous child diagnosed with beta-thalassemia, is concerned about the current pregnancy. Which of the following methods is most likely to establish an accurate prenatal diagnosis for beta-thalassemia?

Chorionic villus sampling. **Explanation:** **1. Why Chorionic Villus Sampling (CVS) is correct:** Beta-thalassemia is a monogenic (single-gene) disorder caused by mutations in the HBB gene. To establish a definitive prenatal diagnosis, **fetal DNA analysis** is required. CVS is the preferred method in this scenario because it can be performed early in pregnancy (**10–13 weeks**). It involves obtaining trophoblastic tissue, which provides sufficient fetal DNA for PCR-based mutation analysis or linkage studies. Early diagnosis allows for safer options regarding pregnancy management if the fetus is affected. **2. Why other options are incorrect:** * **A. Fetal ultrasound:** While ultrasound is vital for structural screening (e.g., nuchal translucency), it cannot detect single-gene mutations like beta-thalassemia, which does not typically present with gross anatomical defects in the first trimester. * **B. Cord blood electrophoresis:** This requires Cordocentesis (Percutaneous Umbilical Blood Sampling), which is usually performed after **18 weeks**. While it can diagnose hemoglobinopathies, it is performed much later than CVS and carries a higher risk of fetal loss. * **D. Buccal mucosal cytology:** This may help determine the carrier status of the parents, but it cannot diagnose the genetic status of the current fetus. **Clinical Pearls for NEET-PG:** * **Gold Standard for DNA diagnosis:** CVS (10–13 weeks) or Amniocentesis (15–20 weeks). * **Thalassemia Screening:** The **Naked Eye Single Tube Red Cell Osmotic Fragility Test (NESTROFT)** is a common screening tool, but **Hb Electrophoresis (HbA2 > 3.5%)** is the confirmatory test for carrier status. * **Preimplantation Genetic Diagnosis (PGD):** An alternative for future pregnancies to avoid termination by testing embryos created via IVF.

Q: A 25-year-old pregnant female at 30 weeks of gestation with uncontrolled gestational diabetes presents for a routine antenatal checkup. Her fundal height is measured at 36 cm, and her abdominal skin appears excessively stretched and shiny. Previous antenatal ultrasounds were normal. What is the most probable diagnosis?

Polyhydramnios. **Explanation:** The clinical presentation of a fundal height significantly greater than the gestational age (36 cm at 30 weeks), combined with "stretched and shiny" abdominal skin, strongly suggests **Polyhydramnios**. In this case, the underlying etiology is **uncontrolled gestational diabetes mellitus (GDM)**. Maternal hyperglycemia leads to fetal hyperglycemia, which causes osmotic diuresis in the fetus, resulting in fetal polyuria and an increase in amniotic fluid volume. **Why the other options are incorrect:** * **Twin gestation:** While twins also cause a "size > dates" discrepancy, the specific mention of uncontrolled GDM and the classic description of shiny, stretched skin (due to rapid fluid accumulation) points more specifically toward polyhydramnios. Furthermore, previous normal ultrasounds would have already identified a multiple pregnancy. * **Uterine fibroids:** Fibroids can increase fundal height, but they are usually associated with a firm, irregular uterine contour rather than the generalized, tense distension seen here. * **Oligohydramnios:** This would present with a fundal height *less* than the gestational age ("size 25 cm or a Single Deepest Pocket (SDP) > 8 cm. * **Common Causes:** Idiopathic (most common), Maternal Diabetes, Fetal structural anomalies (e.g., Esophageal atresia, Anencephaly), and Rh-isoimmunization. * **Clinical Signs:** Difficulty palpating fetal parts and muffled fetal heart sounds are common findings in severe polyhydramnios. * **Complications:** Increased risk of preterm labor, premature rupture of membranes (PROM), cord prolapse, and postpartum hemorrhage (PPH) due to uterine atony.

Q: A 40-year-old female patient in her third trimester of pregnancy, who is on bed rest, complains of breathlessness. What is the primary risk associated with this patient's condition?

High risk for thrombosis. **Explanation:** The correct answer is **A. High risk for thrombosis.** This patient presents with a "perfect storm" of risk factors for Venous Thromboembolism (VTE), specifically Pulmonary Embolism (PE), which is a leading cause of maternal mortality. The underlying medical concept is **Virchow’s Triad**, which consists of: 1. **Hypercoagulability:** Pregnancy is a naturally hypercoagulable state due to increased clotting factors (I, VII, VIII, IX, X) and decreased protein S activity. 2. **Venous Stasis:** The gravid uterus compresses the inferior vena cava, slowing venous return. Crucially, **bed rest** (immobilization) significantly exacerbates this stasis. 3. **Endothelial Injury:** Though not explicitly mentioned, the physiological changes of pregnancy affect vascular integrity. Furthermore, the patient’s **age (40 years)** is an independent risk factor, as maternal age >35 increases VTE risk. **Analysis of Incorrect Options:** * **B & D:** These are incorrect because pregnancy alone increases the risk of thrombosis by 4–5 times compared to non-pregnant women. Adding immobilization and advanced maternal age makes the risk "high," not "low" or "none." * **C:** "Primary thrombosis" is a vague term. In clinical practice, we categorize the risk based on the severity and the need for thromboprophylaxis. **NEET-PG High-Yield Pearls:** * **Most common site** for DVT in pregnancy: Left leg (due to May-Thurner syndrome-like compression of the left common iliac vein by the right common iliac artery). * **Gold standard investigation** for DVT in pregnancy: Compression Duplex Ultrasound. * **Treatment of choice:** Low Molecular Weight Heparin (LMWH). Warfarin is generally avoided due to teratogenicity (except in specific mechanical valve cases). * **Risk Period:** The highest risk period for VTE is actually the **postpartum period** (puerperium).

Q: What is the most common and most poorly tolerated heart disease during pregnancy?

Aortic stenosis. **Explanation** **Correct Answer: C. Aortic Stenosis** In the context of valvular heart disease during pregnancy, **Aortic Stenosis (AS)** is considered the most poorly tolerated. The underlying pathophysiology involves a fixed cardiac output due to the narrowed aortic valve. Pregnancy normally requires a 30–50% increase in cardiac output; however, patients with AS cannot increase their stroke volume to meet this demand. Furthermore, the physiological peripheral vasodilation of pregnancy leads to decreased systemic vascular resistance, which can cause critical hypotension, reduced coronary perfusion, and sudden cardiac death. **Analysis of Incorrect Options:** * **A. Mitral Stenosis:** While this is the **most common** valvular lesion seen in pregnancy (often due to Rheumatic Heart Disease), it is generally better tolerated than severe AS, provided heart rate and fluid balance are managed to prevent pulmonary edema. * **B. Mitral Regurgitation & D. Aortic Regurgitation:** Regurgitant lesions are actually **well-tolerated** during pregnancy. The physiological decrease in systemic vascular resistance (afterload reduction) and the increase in heart rate help improve forward flow and reduce the regurgitant fraction. **High-Yield Clinical Pearls for NEET-PG:** * **Most common heart disease in pregnancy:** Rheumatic Heart Disease (Mitral Stenosis is the most common lesion). * **Most common congenital heart disease in pregnancy:** Atrial Septal Defect (ASD). * **Highest risk of maternal mortality:** Eisenmenger syndrome (up to 50% mortality), followed by Pulmonary Hypertension and Marfan Syndrome with aortic root involvement. * **Management Tip:** For Aortic Stenosis, maintaining preload is vital; avoid sudden vasodilation or dehydration.

Q: All of the following are indications for Anti-D prophylaxis, EXCEPT:

Intrauterine transfusion at 28 weeks gestation. **Explanation:** The core principle of **Anti-D prophylaxis** is to prevent Rh-isoimmunization in an Rh-negative, non-sensitized mother. It is administered whenever there is a risk of **feto-maternal hemorrhage (FMH)**, where Rh-positive fetal red blood cells enter the maternal circulation. **Why Option C is the Correct Answer:** Intrauterine transfusion (IUT) is performed only when the fetus is **already affected** by Rh-isoimmunization (i.e., the mother is already sensitized and has high antibody titers). Anti-D prophylaxis is a **preventive** measure; it is useless once sensitization has occurred. Therefore, a patient requiring IUT is no longer a candidate for Anti-D. **Analysis of Incorrect Options:** * **A. Medical abortion at 6 weeks:** Any pregnancy termination (spontaneous or induced) after 6 weeks carries a risk of FMH. Anti-D (50 mcg) is indicated. * **B. Amniocentesis at 16 weeks:** Invasive prenatal procedures can cause fetal blood to leak into maternal circulation, necessitating Anti-D administration. * **D. Manual removal of the placenta:** This is a high-risk event for significant FMH. Postpartum Anti-D (300 mcg) must be given within 72 hours of delivery if the neonate is Rh-positive. **High-Yield Clinical Pearls for NEET-PG:** * **Standard Dose:** 300 mcg (1500 IU) covers up to 30 mL of fetal whole blood (or 15 mL of RBCs). * **First Trimester Dose:** 50 mcg is sufficient for events before 12–13 weeks. * **Routine Prophylaxis:** Given at 28 weeks gestation to all non-sensitized Rh-negative women. * **Kleihauer-Betke Test:** Used to quantify the volume of FMH to determine if additional doses of Anti-D are required beyond the standard 300 mcg.

Q: What are the chances of vertical transmission of Hepatitis B in women who are seropositive for both HBsAg and HBeAg?

90%. **Explanation:** The risk of vertical transmission of Hepatitis B Virus (HBV) is primarily determined by the maternal viral load and serological status. **1. Why 90% is correct:** HBeAg (Hepatitis B envelope antigen) is a marker of active viral replication and high infectivity. When a pregnant woman is positive for both **HBsAg** (indicating infection) and **HBeAg** (indicating high viral load), the risk of vertical transmission to the neonate is approximately **70–90%** in the absence of immunoprophylaxis. Without intervention, about 90% of these infected infants will go on to develop chronic HBV infection. **2. Why other options are incorrect:** * **A & B (25-40%):** These figures are too low for HBeAg-positive mothers. However, if a mother is **HBsAg positive but HBeAg negative** (and anti-HBe positive), the transmission risk drops significantly to about **10–20%**. * **C (60%):** While transmission rates are high, 60% underestimates the synergistic effect of HBeAg positivity on vertical transmission. **3. High-Yield Clinical Pearls for NEET-PG:** * **Timing of Transmission:** Most vertical transmission occurs **intrapartum** (during delivery) due to contact with maternal blood and vaginal secretions. Transplacental (in-utero) transmission is rare ( 200,000 IU/mL (or $10^6$ copies/mL), Tenofovir is recommended starting at 28–32 weeks of gestation to further reduce the viral load. * **Breastfeeding:** It is **not contraindicated** in HBV-positive mothers, provided the infant receives the birth dose of the vaccine and HBIG.

Q: Which of the following is NOT a criterion for expectant management in pre-eclampsia?

Blood pressure > 140/90 mm Hg. In pre-eclampsia, the decision between expectant management and delivery depends on the severity of the disease and the presence of **"Features of Severity."** **Explanation of the Correct Answer:** **Option B (BP > 140/90 mm Hg)** is the correct answer because it is the **baseline definition** of pre-eclampsia, not a contraindication to expectant management. Expectant management is typically considered in stable patients with "Pre-eclampsia without severe features" between 24 to 34 weeks of gestation. A blood pressure of 140/90 mm Hg is mild; only when BP reaches **≥ 160/110 mm Hg** (Severe Hypertension) does it become a criterion to reconsider expectant management or initiate urgent antihypertensive therapy. **Analysis of Incorrect Options (Criteria for Termination/Severe Features):** Expectant management is contraindicated (or must be terminated) if any of the following severe features develop, as they indicate end-organ damage: * **Option A (Platelets < 100,000/ml):** Indicates thrombocytopenia, a sign of HELLP syndrome or worsening coagulopathy. * **Option C (Urine output < 400 ml/day):** Indicates oliguria and impending renal failure. * **Option D (Persistent headache):** Represents cerebral symptoms (neurological involvement) and is a precursor to eclampsia (seizures). **High-Yield NEET-PG Pearls:** * **Definitive Treatment:** The only definitive cure for pre-eclampsia is the delivery of the placenta. * **Expectant Management Goal:** To improve fetal maturity (administer steroids) without compromising maternal safety. * **Absolute Indications for Delivery:** Eclampsia, Abruptio Placentae, Pulmonary edema, DIC, and Non-reassuring fetal heart rate. * **Magnesium Sulfate ($MgSO_4$):** The drug of choice for seizure prophylaxis in severe pre-eclampsia.

Question 1

A 32-year-old woman, 6 weeks pregnant, with a history of a previous child diagnosed with beta-thalassemia, is concerned about the current pregnancy. Which of the following methods is most likely to establish an accurate prenatal diagnosis for beta-thalassemia?

Accepted Answer

Chorionic villus sampling

Answer

Fetal ultrasound at 12 weeks

Answer

Cord blood electrophoresis

Answer

Buccal mucosal cytology of both parents

Question 2

A 25-year-old pregnant female at 30 weeks of gestation with uncontrolled gestational diabetes presents for a routine antenatal checkup. Her fundal height is measured at 36 cm, and her abdominal skin appears excessively stretched and shiny. Previous antenatal ultrasounds were normal. What is the most probable diagnosis?

Accepted Answer

Polyhydramnios

Answer

Uterine fibroids

Answer

Twin gestation

Answer

Oligohydramnios

Question 3

A 40-year-old female patient in her third trimester of pregnancy, who is on bed rest, complains of breathlessness. What is the primary risk associated with this patient's condition?

Accepted Answer

High risk for thrombosis

Answer

Low risk for thrombosis

Answer

Risk for primary thrombosis

Answer

No risk for thrombosis

Question 4

What is the most common and most poorly tolerated heart disease during pregnancy?

Accepted Answer

Aortic stenosis

Answer

Mitral stenosis

Answer

Mitral regurgitation

Answer

Aortic regurgitation

Question 5

What is the best method to prevent cardiac failure in a pregnant woman with severe mitral stenosis, who is likely to experience failure during the antenatal period?

Accepted Answer

Balloon mitral valvuloplasty in the second trimester

Answer

Furosemide throughout pregnancy

Answer

Digoxin for all patients

Answer

Admission at 30 weeks gestation

Question 6

All of the following are indications for Anti-D prophylaxis, EXCEPT:

Accepted Answer

Intrauterine transfusion at 28 weeks gestation

Answer

Medical abortion at 6 weeks gestation

Answer

Amniocentesis at 16 weeks gestation

Answer

Manual removal of the placenta

Question 7

A 27-year-old woman, gravida 3 para 2, presents at 37 weeks gestation with no prenatal care. She reports sudden, severe back pain after bending down, which has persisted for 2 hours. Approximately 30 minutes prior to arrival, she noted bright red vaginal bleeding. Upon arrival, she is contracting strongly every 3 minutes with a firm uterus between contractions. Fetal presentation is vertex with the head deeply engaged, and the fetal heart rate is 130/min. Fundal height is 38 cm above the symphysis. Blood for clotting is drawn and forms a clot in 4 minutes, with further studies sent to the laboratory. Which of the following actions can wait until the patient is stabilized?

Accepted Answer

Administering oxytocin

Answer

Stabilizing maternal circulation

Answer

Attaching a fetal electronic monitor

Answer

Inserting an intrauterine pressure catheter

Question 8

What are the chances of vertical transmission of Hepatitis B in women who are seropositive for both HBsAg and HBeAg?

Accepted Answer

90%

Answer

25-30%

Answer

40%

Answer

60%

Question 9

What are the findings in ultrasound suggestive of an incompetent internal os?

Accepted Answer

Cervical length, funneling of amniotic sac, AP length of cervix

Answer

Cervical length, external os, internal os

Answer

Cervical length, funneling of amniotic sac

Answer

External os, internal os

Question 10

Which of the following is NOT a criterion for expectant management in pre-eclampsia?

Accepted Answer

Blood pressure > 140/90 mm Hg

Answer

Platelet count < 100,000/ml

Answer

Urine output < 400 ml/day

Answer

Persistent headache

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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