Maternal-Fetal Medicine Practice Questions

Q: Which of the following is NOT a cause of polyhydramnios?

Occult spina bifida. **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).

Q: All are the effects of gestational diabetes on the fetus EXCEPT:

Hypoglycemia. 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.

Q: What is the investigation of choice in a diabetic mother with a doubtful abnormal fetus?

Sonography. **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.

Q: True regarding rubella infection in pregnancy is:

IgM antibodies in fetus reflects immunity. **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.

Q: Biophysical profile includes all except?

Acetylcholine level. 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.

Q: Fetal anemia is detected on Doppler of which artery?

Middle cerebral artery. **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).

Q: Which of the following agents is used for neuroprotection in preterm deliveries?

Magnesium sulphate. **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 1

Which of the following is NOT a cause of polyhydramnios?

Accepted Answer

Occult spina bifida

Answer

Diabetes mellitus

Answer

Swallowing defects in fetus

Answer

Multiple pregnancy

Question 2

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?

Accepted Answer

Monitor the pregnancy with Middle Cerebral Artery (MCA) Peak Systolic Velocity (PSV) values

Answer

Perform weekly Indirect Coombs Test (ICT) for anti-D titres

Answer

Administer anti-D injection at 28 weeks if ICT is negative

Answer

Administer anti-D injection irrespective of the ICT result

Question 3

All are the effects of gestational diabetes on the fetus EXCEPT:

Accepted Answer

Hypoglycemia

Answer

Macrosomia

Answer

Congenital malformations

Answer

Increased perinatal mortality

Question 4

What is the investigation of choice in a diabetic mother with a doubtful abnormal fetus?

Accepted Answer

Sonography

Answer

Glycosylated hemoglobin

Answer

Amniocentesis

Answer

Chorionic villi biopsy

Question 5

What is the best management to prevent heart failure in a pregnant woman with severe mitral stenosis?

Accepted Answer

Balloon mitral valvotomy during the second trimester

Answer

Continuous furosemide therapy throughout pregnancy

Answer

Digoxin for all patients with heart failure

Answer

Admission at 30 weeks gestation

Question 6

True regarding rubella infection in pregnancy is:

Accepted Answer

IgM antibodies in fetus reflects immunity

Answer

Risk of congenital infection is more in last trimester

Answer

Vaccination is indicated in pregnancy for protection

Answer

It is caused by DNA virus

Question 7

Biophysical profile includes all except?

Accepted Answer

Acetylcholine level

Answer

Non-stress test (NST)

Answer

Fetal muscle tone

Answer

Amniotic fluid volume

Question 8

Fetal anemia is detected on Doppler of which artery?

Accepted Answer

Middle cerebral artery

Answer

Uterine artery

Answer

Umbilical artery

Answer

Any of the above

Question 9

Which of the following agents is used for neuroprotection in preterm deliveries?

Accepted Answer

Magnesium sulphate

Answer

Betamethasone

Answer

Dexamethasone

Answer

Indomethacin

Question 10

Which of the following contraceptive methods has the least risk of ectopic pregnancy?

Accepted Answer

Condoms

Answer

Tubectomy

Answer

Oral contraceptive pills

Answer

Intrauterine device (Copper T)

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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