Maternal-Fetal Medicine — MCQs
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Which of the following is NOT a cause of polyhydramnios?
A G4, P1, L0 female presents for antenatal checkup at 12 weeks of gestation. She has had two prior 1st trimester surgical MTPs and delivered a 7-month-old boy in her last pregnancy who died 14 days after birth due to jaundice. Her blood group is B negative, and she was monitored with repeated blood tests during her last pregnancy. There is no history of anti-D administration. What is true regarding her management?
All are the effects of gestational diabetes on the fetus EXCEPT:
What is the investigation of choice in a diabetic mother with a doubtful abnormal fetus?
What is the best management to prevent heart failure in a pregnant woman with severe mitral stenosis?
True regarding rubella infection in pregnancy is:
Biophysical profile includes all except?
Fetal anemia is detected on Doppler of which artery?
Which of the following agents is used for neuroprotection in preterm deliveries?
Which of the following contraceptive methods has the least risk of ectopic pregnancy?
Maternal-Fetal Medicine Indian Medical PG Practice Questions and MCQs
Question 581: Which of the following is NOT a cause of polyhydramnios?
- A. Occult spina bifida (Correct Answer)
- B. Diabetes mellitus
- C. Swallowing defects in fetus
- D. Multiple pregnancy
Explanation: **Explanation:** Polyhydramnios is defined as an Amniotic Fluid Index (AFI) >25 cm or a Single Deepest Pocket (SDP) >8 cm. It occurs due to either overproduction of fetal urine or impaired fetal swallowing. **Why "Occult Spina Bifida" is the correct answer:** In **Open Neural Tube Defects (ONTDs)**, such as *Anencephaly* or *Spina Bifida Cystica*, polyhydramnios occurs because of the transudation of fluid from the exposed meninges and the absence of the swallowing reflex (in anencephaly). However, **Occult Spina Bifida** (Spina Bifida Occulta) is a closed defect where the spinal cord and meninges are covered by skin. Since there is no exposed neural tissue or leakage of cerebrospinal fluid into the amniotic cavity, it does **not** cause polyhydramnios. **Analysis of incorrect options:** * **Diabetes Mellitus:** Maternal hyperglycemia leads to fetal hyperglycemia, causing **osmotic diuresis** and fetal polyuria. * **Swallowing Defects:** Conditions like esophageal atresia, duodenal atresia, or facial clefts prevent the fetus from recycling amniotic fluid, leading to accumulation. * **Multiple Pregnancy:** Specifically in Twin-to-Twin Transfusion Syndrome (TTTS), the recipient twin develops polyuria due to hypervolemia, resulting in polyhydramnios. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of polyhydramnios:** Idiopathic (approx. 50-60%). * **Most common fetal anomaly associated:** Anencephaly. * **Maternal Complications:** Abruptio placentae (due to sudden decompression), Postpartum Hemorrhage (PPH) due to uterine atony, and Cord Prolapse. * **Management:** Therapeutic amniocentesis or Indomethacin (reduces fetal urine output; contraindicated after 32 weeks due to risk of premature closure of Ductus Arteriosus).
Question 582: A G4, P1, L0 female presents for antenatal checkup at 12 weeks of gestation. She has had two prior 1st trimester surgical MTPs and delivered a 7-month-old boy in her last pregnancy who died 14 days after birth due to jaundice. Her blood group is B negative, and she was monitored with repeated blood tests during her last pregnancy. There is no history of anti-D administration. What is true regarding her management?
- A. Monitor the pregnancy with Middle Cerebral Artery (MCA) Peak Systolic Velocity (PSV) values (Correct Answer)
- B. Perform weekly Indirect Coombs Test (ICT) for anti-D titres
- C. Administer anti-D injection at 28 weeks if ICT is negative
- D. Administer anti-D injection irrespective of the ICT result
Explanation: ### Explanation **Core Concept: Rh Isoimmunization Management** The patient is Rh-negative (B negative) with a history strongly suggestive of **Rh isoimmunization**. Her previous child died of jaundice (likely Kernicterus due to Hemolytic Disease of the Fetus and Newborn - HDFN), and she has had multiple sensitizing events (surgical MTPs) without receiving anti-D. In a sensitized pregnancy (ICT positive), the goal is to monitor for fetal anemia. **Why Option A is Correct:** Once a woman is sensitized (has anti-D antibodies), the pregnancy is managed by monitoring fetal well-being. **Middle Cerebral Artery (MCA) Peak Systolic Velocity (PSV)** is the non-invasive gold standard for detecting fetal anemia. In anemic fetuses, blood viscosity decreases and cardiac output increases, leading to a higher PSV. If PSV is >1.5 MoM (Multiples of Median), it indicates severe anemia requiring intrauterine transfusion. **Why Other Options are Incorrect:** * **Option B:** While ICT is used to diagnose sensitization, once a patient is known to be sensitized (based on history/initial titre), serial ICTs are less useful than Doppler for predicting fetal status. Weekly ICT is not standard; it is usually done every 4 weeks until 28 weeks, then every 2 weeks. * **Options C & D:** Anti-D (RhIg) is a **prophylactic** measure. It is only administered to non-sensitized (ICT negative) Rh-negative women. If the patient is already sensitized (ICT positive), anti-D is ineffective and contraindicated as it cannot "neutralize" existing antibodies. **High-Yield Clinical Pearls for NEET-PG:** * **Critical Titre:** In a sensitized pregnancy, the critical ICT titre is usually **1:16** (varies by lab). Below this, the risk of hydrops is low. * **Liley’s Chart:** Historically used to monitor bilirubin in amniotic fluid ($\Delta OD_{450}$); now largely replaced by MCA-PSV Doppler. * **Anti-D Dose:** 300 mcg (standard dose) neutralizes 15 ml of fetal RBCs or 30 ml of fetal whole blood. * **Kleihauer-Betke Test:** Used to quantify the volume of feto-maternal hemorrhage to calculate the required dose of anti-D.
Question 583: All are the effects of gestational diabetes on the fetus EXCEPT:
- A. Macrosomia
- B. Hypoglycemia (Correct Answer)
- C. Congenital malformations
- D. Increased perinatal mortality
Explanation: The correct answer is **B. Hypoglycemia**. ### **Explanation of the Correct Answer** The question asks for the effect of gestational diabetes **on the fetus** (in utero). While **neonatal hypoglycemia** is a very common complication *after* birth, it does not occur in the fetus. * **Pathophysiology:** In a diabetic pregnancy, maternal glucose crosses the placenta, leading to fetal hyperglycemia. The fetal pancreas responds by secreting insulin (fetal hyperinsulinemia). As long as the fetus is in utero, it has a constant supply of glucose from the mother; therefore, it remains hyperglycemic, not hypoglycemic. Hypoglycemia only occurs post-delivery when the maternal glucose supply is cut off, but the high circulating fetal insulin levels persist. ### **Analysis of Incorrect Options** * **A. Macrosomia:** Fetal hyperinsulinemia acts as a growth hormone, leading to increased fat deposition and organomegaly (macrosomia), typically defined as a birth weight >4000g or >4500g. * **C. Congenital Malformations:** While more common in pre-gestational diabetes (PGDM), poorly controlled GDM in early pregnancy also increases the risk of anomalies like sacral agenesis (most specific) and cardiac defects. * **D. Increased Perinatal Mortality:** Uncontrolled GDM increases the risk of stillbirth (IUFD) due to chronic fetal hypoxia, acidosis, and metabolic derangements. ### **High-Yield Clinical Pearls for NEET-PG** * **Most common fetal complication of GDM:** Macrosomia. * **Most common neonatal complication of GDM:** Hypoglycemia. * **Most specific malformation:** Caudal Regression Syndrome (Sacral Agenesis). * **Most common malformation:** Cardiac anomalies (specifically Ventricular Septal Defect). * **Pedersen’s Hypothesis:** Maternal hyperglycemia → Fetal hyperglycemia → Fetal hyperinsulinemia → Macrosomia and neonatal hypoglycemia.
Question 584: What is the investigation of choice in a diabetic mother with a doubtful abnormal fetus?
- A. Sonography (Correct Answer)
- B. Glycosylated hemoglobin
- C. Amniocentesis
- D. Chorionic villi biopsy
Explanation: **Explanation:** In a diabetic mother, the primary concern regarding a "doubtful abnormal fetus" is the presence of **congenital malformations**. Diabetes is a known teratogen, increasing the risk of structural defects (most commonly cardiac and neural tube defects). **1. Why Sonography is the Correct Choice:** Sonography (Targeted Imaging for Fetal Anomalies - TIFFA/Level II scan) is the **investigation of choice** because it allows for the direct, non-invasive visualization of fetal anatomy. It is the gold standard for detecting structural anomalies such as sacral agenesis (caudal regression syndrome), ventricular septal defects, and anencephaly, which are more prevalent in diabetic pregnancies. **2. Analysis of Incorrect Options:** * **Glycosylated Hemoglobin (HbA1c):** While high HbA1c levels in the first trimester correlate with an increased risk of malformations, it is a **predictive marker**, not a diagnostic tool for identifying an existing fetal abnormality. * **Amniocentesis & Chorionic Villi Biopsy (CVS):** These are invasive procedures used primarily for **genetic and chromosomal analysis** (karyotyping). Since maternal diabetes typically causes structural/morphological defects rather than chromosomal aneuploidies, these are not the first-line investigations for a "doubtful abnormal fetus" unless a genetic syndrome is specifically suspected. **Clinical Pearls for NEET-PG:** * **Most common anomaly** in infants of diabetic mothers: **Cardiac defects** (specifically VSD). * **Most specific anomaly** for diabetes: **Caudal Regression Syndrome** (Sacral agenesis). * **Best time for anomaly scan:** 18–20 weeks of gestation. * Poor glycemic control (HbA1c >8.5%) significantly increases the risk of congenital malformations.
Question 585: What is the best management to prevent heart failure in a pregnant woman with severe mitral stenosis?
- A. Continuous furosemide therapy throughout pregnancy
- B. Balloon mitral valvotomy during the second trimester (Correct Answer)
- C. Digoxin for all patients with heart failure
- D. Admission at 30 weeks gestation
Explanation: **Explanation:** **Mitral Stenosis (MS)** is the most common valvular lesion encountered in pregnancy, usually secondary to Rheumatic Heart Disease. In severe MS, the physiological increase in blood volume and heart rate during pregnancy leads to elevated left atrial pressure, significantly increasing the risk of pulmonary edema and heart failure. **Why Option B is Correct:** **Percutaneous Transvenous Mitral Commissurotomy (PTMC)**, also known as Balloon Mitral Valvotomy, is the procedure of choice for symptomatic severe MS during pregnancy. The **second trimester** (ideally after 20 weeks) is the optimal time because organogenesis is complete, the fetal thyroid is less sensitive to radiation, and the hemodynamic burden of pregnancy has not yet reached its peak (which occurs at 28–32 weeks). It provides a definitive mechanical solution to the obstruction. **Why Other Options are Incorrect:** * **Option A:** While diuretics like furosemide are used to manage pulmonary congestion, they are not used "continuously throughout pregnancy" as a preventive measure because they can decrease placental perfusion. * **Option C:** Digoxin is only indicated if there is associated atrial fibrillation or concurrent left ventricular systolic failure; it is not a standard treatment for MS with sinus rhythm. * **Option D:** While close monitoring is required, admission at 30 weeks is a supportive measure and does not "prevent" heart failure as effectively as correcting the mechanical valve obstruction. **Clinical Pearls for NEET-PG:** * **Most critical periods for heart failure:** 28–32 weeks gestation, during labor (second stage), and the immediate postpartum period (due to autotransfusion). * **Target Heart Rate:** Beta-blockers (e.g., Metoprolol) are the first-line medical therapy to increase diastolic filling time. * **NYHA Class:** Patients in NYHA Class III or IV who do not respond to medical therapy must undergo PTMC. * **Contraindication:** Warfarin is contraindicated in the first trimester (teratogenic) and near term (fetal hemorrhage).
Question 586: True regarding rubella infection in pregnancy is:
- A. Risk of congenital infection is more in last trimester
- B. Vaccination is indicated in pregnancy for protection
- C. IgM antibodies in fetus reflects immunity (Correct Answer)
- D. It is caused by DNA virus
Explanation: **Explanation:** **Why Option C is Correct:** The detection of **IgM antibodies** in the fetus or neonate is diagnostic of a congenital infection. Unlike IgG, maternal IgM antibodies are large molecules that **cannot cross the placenta**. Therefore, if IgM is present in the fetal blood (usually detected via cordocentesis after 22 weeks) or in the newborn, it indicates that the fetus has mounted its own immune response to an active infection. In the context of this question, it "reflects immunity" in the sense of an endogenous fetal immune response to the virus. **Analysis of Incorrect Options:** * **Option A:** The risk of **congenital transmission** is actually highest in the **first trimester** (up to 80-90%) and again very late in the third trimester. However, the risk of **congenital malformations** (Congenital Rubella Syndrome) is highest if the infection occurs before 12 weeks and is virtually zero after 20 weeks. * **Option B:** The Rubella vaccine (MMR) is a **Live Attenuated Vaccine**. It is strictly **contraindicated during pregnancy** due to the theoretical risk of infecting the fetus. Women should be advised to avoid pregnancy for at least 1 month (28 days) after vaccination. * **Option D:** Rubella is caused by the Rubivirus, which is a **positive-sense, single-stranded RNA virus** (Togaviridae family), not a DNA virus. **High-Yield Clinical Pearls for NEET-PG:** * **Gregg’s Triad:** The classic presentation of Congenital Rubella Syndrome (CRS) includes **Cataracts, Sensorineural hearing loss (most common), and Cardiac defects** (PDA is most common; Peripheral Pulmonary Artery Stenosis is most specific). * **Blueberry Muffin Rash:** Seen in neonates due to extramedullary hematopoiesis. * **Diagnosis:** If a pregnant woman is exposed, the first step is to check her **IgG status**. If she is IgG positive, she is immune and the fetus is safe.
Question 587: Biophysical profile includes all except?
- A. Non-stress test (NST)
- B. Fetal muscle tone
- C. Amniotic fluid volume
- D. Acetylcholine level (Correct Answer)
Explanation: The **Biophysical Profile (BPP)**, also known as Manning’s score, is a critical ultrasound-based assessment used to evaluate fetal well-being and identify fetal hypoxia. It consists of five specific parameters, each reflecting the integrity of the fetal central nervous system. ### Why Acetylcholine level is the correct answer: **Acetylcholine level** is not a component of the BPP. While biochemical markers like Alpha-fetoprotein or Acetylcholinesterase are measured in amniotic fluid to screen for neural tube defects, they play no role in the acute assessment of fetal oxygenation or behavioral states. ### Explanation of BPP Components (The Incorrect Options): The BPP evaluates five parameters, scoring each as either 2 (normal) or 0 (abnormal): 1. **Non-stress test (NST):** Assesses fetal heart rate reactivity (the only "non-ultrasound" component). 2. **Fetal muscle tone:** At least one episode of active extension with return to flexion of fetal limbs or trunk. 3. **Amniotic fluid volume:** A marker of chronic fetal well-being (at least one pocket of $2 \text{ cm} \times 2 \text{ cm}$). 4. **Fetal breathing movements:** At least one episode of $\geq 30$ seconds duration within 30 minutes. 5. **Gross body movements:** At least three discrete body or limb movements in 30 minutes. ### High-Yield Clinical Pearls for NEET-PG: * **Modified BPP:** Consists of only two parameters: **NST** (acute indicator) and **Amniotic Fluid Index** (chronic indicator). * **Sequence of Loss:** In progressive fetal acidemia, the first parameter to disappear is the **NST (reactivity)**, followed by breathing, then movement, and finally **tone** (the last to disappear). * **Scoring:** A score of **8–10** is normal; **4 or less** is strongly suggestive of fetal asphyxia and usually warrants immediate delivery.
Question 588: Fetal anemia is detected on Doppler of which artery?
- A. Uterine artery
- B. Umbilical artery
- C. Middle cerebral artery (Correct Answer)
- D. Any of the above
Explanation: **Explanation:** The **Middle Cerebral Artery (MCA)** is the vessel of choice for detecting fetal anemia. The underlying physiological principle is the **"Brain Sparing Effect"** and changes in blood viscosity. When a fetus is anemic, the blood becomes less viscous (thinner), leading to an increased velocity of blood flow. Additionally, the fetus compensates for hypoxia/anemia by diverting blood to the brain. In clinical practice, we measure the **Peak Systolic Velocity (PSV)** of the MCA. A value **>1.5 MoM (Multiples of Median)** for the corresponding gestational age is highly sensitive for identifying moderate-to-severe fetal anemia (e.g., due to Rh isoimmunization or Parvovirus B19 infection). **Why other options are incorrect:** * **Uterine Artery:** Doppler of this maternal vessel is used to assess placental perfusion. It is primarily used to screen for the risk of **Pre-eclampsia** and **Intrauterine Growth Restriction (IUGR)** (look for "diastolic NOTCH"). * **Umbilical Artery:** This reflects placental vascular resistance. It is used to monitor **fetal well-being in IUGR** (looking for absent or reversed end-diastolic flow), but it does not reliably change in response to anemia. **High-Yield Clinical Pearls for NEET-PG:** * **MCA-PSV** is the most sensitive non-invasive test for fetal anemia, replacing the invasive Liley’s Chart (amniocentesis). * **Ductus Venosus:** Abnormal flow (absent/reversed 'a' wave) indicates fetal cardiac failure and is a late sign of fetal distress. * **Gold Standard for Diagnosis:** If MCA-PSV is >1.5 MoM, the definitive diagnosis and treatment (intrauterine transfusion) are performed via **Cordocentesis** (Percutaneous Umbilical Blood Sampling).
Question 589: Which of the following agents is used for neuroprotection in preterm deliveries?
- A. Betamethasone
- B. Dexamethasone
- C. Magnesium sulphate (Correct Answer)
- D. Indomethacin
Explanation: **Explanation:** **Magnesium Sulphate (MgSO₄)** is the drug of choice for fetal neuroprotection in anticipated preterm deliveries. When administered to mothers at risk of delivery before 32 weeks of gestation, it significantly reduces the risk of **cerebral palsy** and severe motor dysfunction in the offspring. The underlying mechanism involves stabilizing neuronal membranes, reducing pro-inflammatory cytokines, and inhibiting excitatory neurotransmitters like glutamate by blocking NMDA receptors. **Analysis of Incorrect Options:** * **Betamethasone & Dexamethasone (Options A & B):** These are antenatal corticosteroids used to accelerate **fetal lung maturity**. While they reduce the incidence of Respiratory Distress Syndrome (RDS), Intraventricular Hemorrhage (IVH), and Necrotizing Enterocolitis (NEC), they are not primarily classified as neuroprotective agents for cerebral palsy. * **Indomethacin (Option D):** This is a non-steroidal anti-inflammatory drug (NSAID) used as a **tocolytic** to delay preterm labor. It acts by inhibiting prostaglandin synthesis. It is generally avoided after 32 weeks due to the risk of premature closure of the ductus arteriosus. **High-Yield Clinical Pearls for NEET-PG:** * **Gestational Age:** MgSO₄ for neuroprotection is typically recommended for deliveries **<32 weeks** (some protocols say <30 weeks). * **Dosing:** Usually a 4g IV loading dose followed by a 1g/hour maintenance infusion for 24 hours or until delivery. * **Monitoring:** Always monitor for **Magnesium toxicity** (loss of patellar reflex is the first sign, followed by respiratory depression). * **Antidote:** Calcium Gluconate (10ml of 10% solution IV).
Question 590: Which of the following contraceptive methods has the least risk of ectopic pregnancy?
- A. Tubectomy
- B. Oral contraceptive pills
- C. Intrauterine device (Copper T)
- D. Condoms (Correct Answer)
Explanation: **Explanation:** The risk of ectopic pregnancy in contraceptive users must be understood through two different lenses: **absolute risk** (the chance of an ectopic pregnancy occurring per 1,000 women) and **relative risk** (the proportion of pregnancies that are ectopic if the method fails). **Why Condoms are the correct answer:** Condoms have the **least absolute risk** of ectopic pregnancy because they are highly effective at preventing **conception** altogether. By preventing the union of sperm and ovum, they reduce the total number of pregnancies. Since the total number of pregnancies is very low, the mathematical probability of an ectopic pregnancy occurring is the lowest among the given options. **Analysis of Incorrect Options:** * **Oral Contraceptive Pills (OCPs):** While OCPs also have a very low absolute risk because they inhibit ovulation, they are statistically slightly less effective in "typical use" compared to the consistent barrier protection or the systemic suppression of some other methods. However, they are still safer than IUDs regarding ectopic risk. * **Intrauterine Device (Copper T):** IUDs do not prevent ovulation; they prevent implantation. If an IUD fails, there is a **high relative risk** that the resulting pregnancy will be ectopic (approx. 5-15%) because the device prevents intrauterine implantation more effectively than extrauterine implantation. * **Tubectomy:** This is a high-yield trap. While tubectomy is a permanent sterilization method, if it fails (e.g., due to recanalization or fistula formation), the **relative risk** of ectopic pregnancy is the **highest** among all methods. **NEET-PG High-Yield Pearls:** 1. **Lowest Absolute Risk:** Condoms (followed by OCPs). 2. **Highest Relative Risk (if failure occurs):** Tubectomy (specifically Bipolar Cautery). 3. **Most common site of Ectopic Pregnancy:** Ampulla of the Fallopian tube. 4. **Key Concept:** Any method that prevents ovulation (OCPs) or fertilization (Condoms) carries a lower absolute risk of ectopic pregnancy than methods that primarily act on the endometrium (IUDs).
Practice by Chapter
Fetal Assessment Techniques
Practice Questions
Hypertensive Disorders in Pregnancy
Practice Questions
Intrauterine Growth Restriction
Practice Questions
Multiple Gestation
Practice Questions
Rh Isoimmunization and Other Blood Group Incompatibilities
Practice Questions
Intrauterine Fetal Therapy
Practice Questions
Prenatal Diagnosis and Genetic Counseling
Practice Questions
Placental Abnormalities
Practice Questions
Preterm Labor and Delivery
Practice Questions
Management of Medical Disorders in Pregnancy
Practice Questions
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