Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine Indian Medical PG Practice Questions and MCQs

Question 401: What period carries the highest risk of HIV transmission?

A. During Caesarean section
B. During the antepartum period
C. During vaginal delivery (Correct Answer)
D. Breastfeeding

Explanation: **Explanation:** The risk of Mother-to-Child Transmission (MTCT) of HIV occurs at three distinct stages: antepartum (in utero), intrapartum (during labor and delivery), and postpartum (via breastfeeding). **Why Option C is correct:** The **intrapartum period** (during vaginal delivery) carries the highest risk of transmission, accounting for approximately **60-75%** of cases in non-breastfeeding women. This is due to "micro-transfusions" occurring during uterine contractions and the direct exposure of the fetus to infected maternal blood and cervicovaginal secretions in the birth canal. **Analysis of Incorrect Options:** * **A. Caesarean Section:** Elective (pre-labor) C-section actually *reduces* the risk of transmission by avoiding the birth canal and labor contractions. It is recommended if the maternal viral load is >1000 copies/mL. * **B. Antepartum Period:** While transmission can occur via the placenta, it accounts for only about **20-25%** of cases, primarily occurring in the late third trimester. * **D. Breastfeeding:** This contributes to roughly **10-15%** of the total risk if the mother is not on ART. While significant, the cumulative risk is lower than the acute risk during the intrapartum window. **High-Yield Clinical Pearls for NEET-PG:** * **Risk Distribution:** Without intervention, the risk is roughly 15-25% in non-breastfeeding women and 25-45% in breastfeeding women. * **Most Important Predictor:** Maternal **plasma viral load** is the strongest predictor of transmission risk. * **Zidovudine (AZT):** Historically the cornerstone of prevention; however, current WHO/NACO guidelines recommend **Life-long ART (TLD regimen)** for all pregnant and breastfeeding women regardless of CD4 count (Option B+ strategy). * **Infant Prophylaxis:** In India, Nevirapine syrup is typically given to the infant for 6 weeks.

Question 402: Which of the following antihypertensives is NOT used in the management of pregnancy-induced hypertension in the first trimester?

A. Hydralazine
B. Atenolol (Correct Answer)
C. Labetalol
D. Nifedipine

Explanation: **Explanation:** The management of hypertension in pregnancy requires balancing maternal blood pressure control with fetal safety. **Atenolol** is generally avoided in pregnancy, particularly in the first trimester, because it is associated with **fetal growth restriction (FGR)**, placental weight reduction, and potential neonatal complications like bradycardia and hypoglycemia. Unlike other beta-blockers, atenolol’s specific association with significant intrauterine growth restriction makes it a suboptimal choice compared to safer alternatives. **Analysis of Options:** * **Labetalol (Option C):** This is the **first-line drug of choice** for chronic and gestational hypertension. It is a combined alpha and beta-blocker with a proven safety profile throughout pregnancy. * **Nifedipine (Option D):** A calcium channel blocker (long-acting formulation) frequently used as a first-line or second-line agent. It is safe and effective for long-term management. * **Hydralazine (Option A):** A direct vasodilator primarily used for the acute management of **hypertensive emergencies** in pregnancy (e.g., severe preeclampsia). While not first-line for routine control, it is not contraindicated. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** Labetalol is the overall DOC for hypertension in pregnancy. * **Acute Hypertensive Crisis:** IV Labetalol or IV Hydralazine are preferred. * **Absolute Contraindications:** **ACE Inhibitors** (e.g., Enalapril) and **ARBs** (e.g., Losartan) are strictly contraindicated as they cause fetal renal dysgenesis, oligohydramnios, and skull defects. * **Methyldopa:** Historically the DOC; it remains a safe option but is now often considered second-line due to its slow onset and side-effect profile (sedation).

Question 403: Which of the following is true for the ratio of fresh placental weight to infant weight in the last trimester of pregnancy?

A. 1:2
B. 2:1
C. 1:6 (Correct Answer)
D. 6:1

Explanation: The placental-fetal weight ratio is a critical indicator of placental efficiency and fetal growth. In a healthy, term pregnancy, the placenta weighs approximately **one-sixth** of the infant's weight. ### **Detailed Explanation** 1. **Correct Answer (C): 1:6** At full term (approx. 40 weeks), a normal placenta weighs about **500 grams**, while a healthy newborn weighs approximately **3000–3500 grams**. This results in a ratio of roughly **1:6**. This ratio is not constant throughout pregnancy; the placenta is actually heavier than the fetus in early gestation, but the fetus grows at a much faster rate during the third trimester, leading to the 1:6 ratio at term. 2. **Incorrect Options (A, B, D):** * **1:2 (A):** This ratio would imply a massive placenta (e.g., a 1.5kg placenta for a 3kg baby), which is pathological and seen only in severe cases of hydrops fetalis or congenital syphilis. * **2:1 and 6:1 (B, D):** These ratios suggest the placenta is significantly heavier than the baby. While the placenta is heavier than the embryo in the first trimester (around 10-12 weeks), these ratios are never seen in the third trimester. ### **NEET-PG High-Yield Pearls** * **Placental Weight:** Approximately 500g at term (1/6th of fetal weight). * **Placental Diameter:** 15–20 cm; **Thickness:** 2.5–3 cm at the center. * **Increased Ratio (>1:6):** Seen in **Diabetes Mellitus**, Rh-isoimmunization (Hydrops), Syphilis, and Multiple gestations. A "large" placenta often indicates a need for increased surface area to compensate for poor oxygen transfer. * **Decreased Ratio (<1:6):** Seen in **Preeclampsia**, chronic hypertension, and severe IUGR, where placental insufficiency leads to a small, infarcted placenta. * **Number of Cotyledons:** 15–20 lobes (functional units).

Question 404: A 24-year-old pregnant woman at 36 weeks gestation presents with sudden onset headache and blurred vision. Her blood pressure is 170/110 mm Hg. Urinalysis reveals albumin +++ and fundus examination shows retinal hemorrhages. What is the most appropriate next step in management?

A. Conservative treatment
B. Anticonvulsive therapy (Correct Answer)
C. Induction of labor
D. Cesarean delivery

Explanation: **Explanation:** The patient presents with the classic triad of **Severe Preeclampsia**: severe hypertension (≥160/110 mm Hg), significant proteinuria (+++), and "imminent symptoms" (headache, visual disturbances, and retinal hemorrhages). These symptoms indicate cerebral and retinal edema, signaling that the patient is at high risk for progressing to **Eclampsia** (seizures). **Why Anticonvulsive Therapy is Correct:** In the management of severe preeclampsia, the immediate priority is the **prevention of seizures** and stabilization of the mother. **Magnesium Sulfate (MgSO₄)** is the drug of choice for seizure prophylaxis. While delivery is the definitive cure for preeclampsia, the patient must be stabilized first with anticonvulsants and antihypertensives to prevent life-threatening complications like intracranial hemorrhage or status epilepticus during the delivery process. **Why Other Options are Incorrect:** * **A. Conservative treatment:** This is contraindicated in severe preeclampsia at 36 weeks. Delaying treatment increases the risk of maternal stroke, placental abruption, and fetal demise. * **C & D. Induction of labor / Cesarean delivery:** While delivery is the ultimate treatment, it is the *second* step. You must "stabilize then deliver." Performing a delivery or induction without first administering MgSO₄ and controlling blood pressure puts the patient at maximum risk for intrapartum eclampsia. **NEET-PG High-Yield Pearls:** * **Drug of Choice:** Magnesium Sulfate (Pritchard Regimen or Zuspan Regimen). * **Therapeutic Level of MgSO₄:** 4–7 mEq/L. * **First Sign of Toxicity:** Loss of patellar reflex (Knee jerk). * **Antidote:** Calcium Gluconate (10 ml of 10% solution IV). * **Target BP:** Aim to lower MAP by 20-25%, maintaining diastolic BP between 90-100 mm Hg to prevent placental hypoperfusion.

Question 405: Regarding HIV transmission to the fetus, all statements are true except?

A. More than 50% risk of transmission to the fetus
B. Can present as failure to thrive (Correct Answer)
C. Greatest risk of transmission is in the perinatal period
D. Cannot be diagnosed

Explanation: In the context of HIV in pregnancy, the question asks for the **incorrect** statement (the "except"). ### **Explanation of the Correct Answer** **Option B (Can present as failure to thrive)** is the correct answer because it is a **true** statement regarding pediatric HIV. However, in the context of this specific question's construction (which appears to be a "negative" question format common in NEET-PG), the statement "Cannot be diagnosed" (Option D) is the most factually incorrect. *Note: If the question asks for the "Except" and Option B is marked as correct in your key, it implies the question is asking which statement is NOT a characteristic of maternal-fetal transmission. However, clinically, HIV-infected infants **do** present with failure to thrive, making Option D the only absolute falsehood.* ### **Analysis of Options** * **A. More than 50% risk of transmission:** In the absence of any intervention (ART, elective LSCS, or avoidance of breastfeeding), the transmission risk is approximately 25-40%. With modern HAART and viral suppression, this risk drops to **<1-2%**. * **C. Greatest risk is in the perinatal period:** This is **True**. Approximately 65-75% of transmissions occur during labor and delivery due to exposure to maternal blood and vaginal secretions. * **D. Cannot be diagnosed:** This is **False**. HIV in infants is diagnosed using **HIV DNA PCR** (Virological testing) because maternal IgG antibodies cross the placenta, making standard ELISA unreliable until 18 months of age. ### **High-Yield Clinical Pearls for NEET-PG** 1. **Timing of Transmission:** Antepartum (20%), Intrapartum (60-70%), Postpartum via breastfeeding (10-15%). 2. **Drug of Choice:** All pregnant women should be on **TDF + 3TC + EFV** (or Dolutegravir-based regimens) regardless of CD4 count. 3. **Infant Prophylaxis:** Nevirapine syrup is given for 6 weeks. 4. **Mode of Delivery:** Vaginal delivery is safe if the viral load is <1000 copies/mL. Elective LSCS is preferred if the viral load is >1000 copies/mL. 5. **Breastfeeding:** In India (NACO guidelines), exclusive breastfeeding is recommended for the first 6 months, followed by complementary feeding. Mixed feeding should be strictly avoided.

Question 406: What is the indication of acyclovir in pregnancy?

A. Disseminated herpes
B. Chickenpox in first trimester
C. Prophylaxis in recurrent herpes
D. All of the above (Correct Answer)

Explanation: Acyclovir is a category B drug and is considered safe and effective for various indications during pregnancy to prevent both maternal complications and vertical transmission. **Explanation of Options:** * **Disseminated Herpes (Option A):** This is a life-threatening condition for the mother (causing hepatitis, encephalitis, or pneumonitis). Intravenous acyclovir is the gold standard treatment to reduce maternal mortality. * **Chickenpox in First Trimester (Option B):** While the risk of Congenital Varicella Syndrome is highest in the first 20 weeks, acyclovir is indicated to reduce the severity of maternal disease and potentially decrease the risk of transplacental transmission. * **Prophylaxis in Recurrent Herpes (Option C):** In women with a history of recurrent Genital Herpes (HSV), suppressive therapy with acyclovir is started at **36 weeks of gestation**. This reduces the risk of active lesions at the time of labor, thereby decreasing the need for Cesarean sections. **Why "All of the above" is correct:** Acyclovir is indicated whenever the benefits of treating a viral infection (preventing maternal systemic spread or neonatal transmission) outweigh the minimal risks of the drug. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Oral Acyclovir is the DOC for genital herpes; IV Acyclovir is the DOC for Varicella pneumonia or HSV encephalitis in pregnancy. * **Timing for Varicella:** For maximum efficacy in chickenpox, acyclovir should be started within **24 hours** of the appearance of the rash. * **Neonatal Prophylaxis:** If a mother has active herpetic lesions during labor, a **Cesarean section** is indicated to prevent Neonatal Herpes Simplex. * **Varicella Zoster Immunoglobulin (VZIG):** Should be given to non-immune pregnant women within 96 hours of exposure to chickenpox.

Question 407: In a primigravida with mechanical heart valves, at which gestational week is intravenous heparin typically introduced?

A. 32 weeks
B. 36 weeks (Correct Answer)
C. 40 weeks
D. At the time of labor

Explanation: **Explanation:** The management of anticoagulation in pregnant women with mechanical heart valves is a high-stakes clinical scenario due to the competing risks of maternal valve thrombosis and fetal hemorrhage/teratogenicity. **Why 36 weeks is correct:** The primary goal of switching from oral anticoagulants (like Warfarin) or Low Molecular Weight Heparin (LMWH) to **Intravenous Unfractionated Heparin (IV UFH)** at **36 weeks** is to prepare for labor. Warfarin crosses the placenta and can cause fetal intracranial hemorrhage during the physical stress of delivery. UFH is preferred late in pregnancy because it does not cross the placenta and has a very short half-life (approx. 1–2 hours). This allows for rapid reversal or cessation of anticoagulation once labor begins, ensuring safe administration of regional anesthesia (epidural) and minimizing postpartum hemorrhage. **Analysis of Incorrect Options:** * **A. 32 weeks:** This is too early. Transitioning to IV UFH requires hospitalization for monitoring (aPTT); starting at 32 weeks unnecessarily increases the duration of inpatient care without added benefit for a term delivery. * **C. 40 weeks:** This is too late. Many women go into spontaneous labor before 40 weeks. Waiting until the due date risks the patient being on long-acting anticoagulants or Warfarin when labor starts. * **D. At the time of labor:** Transitioning only at labor is dangerous. If a patient is on Warfarin or LMWH when labor begins, the risk of maternal and fetal bleeding is significantly elevated, and the effects cannot be "turned off" quickly. **NEET-PG High-Yield Pearls:** * **Warfarin Embryopathy:** Most common if used between **6–12 weeks** (stippled epiphyses, nasal hypoplasia). * **Preferred Regimen:** Often involves LMWH or Warfarin in the 2nd and 3rd trimesters, but **always** switch to IV UFH at 36 weeks. * **Monitoring:** UFH is monitored using **aPTT** (target 2–3 times control), while LMWH is monitored using **Anti-Xa levels**. * **Restarting:** Anticoagulation is typically restarted 6–12 hours after an uncomplicated vaginal delivery.

Question 408: What is the most common complication due to expectant management of preeclampsia?

A. Acute renal failure
B. Pulmonary edema
C. Cardiac arrest
D. Placental abruption (Correct Answer)

Explanation: **Explanation:** The goal of expectant management in preeclampsia (typically practiced between 24 and 34 weeks of gestation) is to improve neonatal outcomes by allowing for fetal growth and lung maturation. However, this prolongs exposure to a pathophysiological state characterized by systemic vasospasm and endothelial dysfunction. **Why Placental Abruption is the Correct Answer:** Placental abruption is the **most common maternal complication** associated with the expectant management of preeclampsia. The underlying mechanism involves chronic placental ischemia and high systemic vascular resistance, which leads to rupture of the maternal spiral arteries into the decidua basalis. Studies indicate that in patients undergoing expectant management for severe preeclampsia, the incidence of abruption is significantly higher compared to the general obstetric population. **Analysis of Incorrect Options:** * **A. Acute Renal Failure:** While preeclampsia causes glomerular endotheliosis and reduced GFR, frank acute renal failure is less common than abruption unless complicated by HELLP syndrome or massive hemorrhage. * **B. Pulmonary Edema:** This is a life-threatening complication usually triggered by iatrogenic fluid overload or left ventricular failure, but it occurs less frequently than abruption. * **C. Cardiac Arrest:** This is an extremely rare, terminal event and not a standard "common" complication of expectant management. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of death in Preeclampsia:** Cerebral Hemorrhage (Stroke). * **Most common maternal complication of expectant management:** Placental Abruption. * **Indication for immediate delivery:** Signs of maternal/fetal deterioration (e.g., eclampsia, persistent severe headache, pulmonary edema, or non-reassuring CTG) regardless of gestational age. * **Drug of choice for seizure prophylaxis:** Magnesium Sulfate ($MgSO_4$).

Question 409: Which of the following is NOT a cause of intrauterine fetal death?

A. Pregnancy-induced hypertension (PIH) (Correct Answer)
B. Disseminated intravascular coagulation (DIC)
C. Psychological upset
D. Infection

Explanation: ### Explanation The objective of this question is to identify which factor is a **consequence** rather than a **cause** of intrauterine fetal death (IUFD). **Why Option B is the Correct Answer (The Medical Concept):** In the context of IUFD, **Disseminated Intravascular Coagulation (DIC)** is a potential *complication* of fetal demise, not the cause. When a dead fetus is retained in the uterus for more than 3–4 weeks, thromboplastin-like substances from the decomposing fetal tissues and placenta enter the maternal circulation. This triggers the extrinsic coagulation pathway, leading to consumption coagulopathy (DIC). Therefore, DIC follows IUFD; it does not initiate it. **Analysis of Other Options (Causes of IUFD):** * **Pregnancy-induced hypertension (PIH):** This is a leading cause of IUFD. Severe pre-eclampsia or eclampsia leads to placental insufficiency, chronic hypoxia, or abruptio placentae, all of which can result in fetal death. * **Infection:** Maternal infections (e.g., TORCH, Listeria, Syphilis) or ascending chorioamnionitis can lead to fetal sepsis and death. * **Psychological upset:** While less common, severe acute maternal stress or psychological trauma can trigger catecholamine release, potentially leading to uterine artery vasoconstriction and compromised fetal oxygenation. **NEET-PG High-Yield Pearls:** * **Most common cause of IUFD:** Idiopathic (unexplained) in nearly 25–50% of cases. Among known causes, maternal hypertension is the most frequent. * **The "4-Week Rule":** The risk of DIC becomes significant if a dead fetus is retained for >4 weeks. * **Diagnostic Gold Standard:** Real-time Ultrasound showing absence of fetal heart activity. * **Spalding’s Sign:** Overlapping of skull bones (due to liquefaction of the brain) seen on X-ray/USG, usually appearing 4–7 days after death. * **Robert’s Sign:** Appearance of gas shadows in the fetal heart and great vessels (earliest radiological sign, seen within 12 hours).

Question 410: Which of the following complications can be caused by smoking during pregnancy?

A. Intrauterine growth restriction (IUGR) and post-term delivery (PTD) (Correct Answer)
B. Post-term delivery (PTD) and abruptio placentae (APH)
C. Intrauterine growth restriction (IUGR) and abruptio placentae (APH)
D. Post-term delivery (PTD)

Explanation: **Explanation:** Smoking during pregnancy is a significant risk factor for adverse obstetric outcomes due to the combined effects of **carbon monoxide** (which causes fetal hypoxia by forming carboxyhemoglobin) and **nicotine** (a potent vasoconstrictor that reduces uteroplacental blood flow). **Why Option A is Correct:** * **Intrauterine Growth Restriction (IUGR):** Chronic hypoxia and reduced nutrient transfer across the placenta lead to symmetrical or asymmetrical growth restriction. Smoking is one of the most common modifiable causes of low birth weight. * **Preterm Delivery (PTD):** Smoking is strongly associated with **Preterm Birth** (not post-term). It increases the risk of Preterm Premature Rupture of Membranes (PPROM) and placental complications that necessitate early delivery. *(Note: In many standard texts and exams, "PTD" refers to Preterm Delivery. If the option intended Post-term, it would be clinically incorrect as smoking is associated with early, not late, delivery).* **Analysis of Incorrect Options:** * **Options B, C, and D:** While **Abruptio Placentae** is a known complication of smoking (due to decidual necrosis and vascular damage), any option containing **Post-term delivery** is incorrect. Smoking typically shortens gestation; it does not prolong it. **NEET-PG High-Yield Pearls:** * **Dose-Response Relationship:** The reduction in birth weight is directly proportional to the number of cigarettes smoked per day. * **Placental Changes:** Smoking increases the risk of **Placenta Previa** and **Abruptio Placentae**. * **Fetal Risks:** Increased risk of Orofacial clefts (cleft lip/palate), Sudden Infant Death Syndrome (SIDS), and childhood respiratory infections. * **Key Toxin:** Carbon monoxide has a 200x higher affinity for fetal hemoglobin than oxygen, leading to a "smothering" effect on the fetus.

Practice by Chapter

Fetal Assessment Techniques

Practice Questions

Hypertensive Disorders in Pregnancy

Practice Questions

Intrauterine Growth Restriction

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Multiple Gestation

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Rh Isoimmunization and Other Blood Group Incompatibilities

Practice Questions

Intrauterine Fetal Therapy

Practice Questions

Prenatal Diagnosis and Genetic Counseling

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Placental Abnormalities

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Preterm Labor and Delivery

Practice Questions

Management of Medical Disorders in Pregnancy

Practice Questions

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