Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine Indian Medical PG Practice Questions and MCQs

Question 201: All of the following are associated with placental abruption, EXCEPT?

A. Cocaine abuse
B. Cigarette smoking
C. Hypotension (Correct Answer)
D. Pre-eclampsia

Explanation: **Explanation:** Placental abruption (Abruptio Placentae) is the premature separation of a normally situated placenta from the uterine wall. The primary pathophysiology involves **vascular disruption** and **hypertension**, not hypotension. **Why Hypotension is the Correct Answer:** **Hypertension** (both chronic and pregnancy-induced) is the most significant risk factor for abruption. High blood pressure causes degenerative changes in the spiral arteries, leading to hemorrhage into the decidua basalis. **Hypotension** is a *consequence* of the resulting blood loss (hypovolemic shock) rather than a predisposing cause. **Analysis of Incorrect Options:** * **Cocaine abuse:** Cocaine is a potent vasoconstrictor that causes acute, severe maternal hypertension and uterine artery vasospasm, leading to placental shearing. * **Cigarette smoking:** Nicotine and carbon monoxide cause decidual hypoxemia and vascular necrosis. Smokers have a 2-fold increased risk of abruption. * **Pre-eclampsia:** This is the most common pathological condition associated with abruption. The underlying widespread endothelial dysfunction and vasospasm directly predispose the placenta to separation. **NEET-PG High-Yield Pearls:** * **Most common risk factor:** Previous history of abruption (recurrence risk is 5–15%). * **Most common "preventable" risk factor:** Maternal Hypertension. * **Clinical Triad:** Painful vaginal bleeding, uterine tenderness/rigidity (woody hard uterus), and fetal distress. * **Couvelaire Uterus:** A complication where retroplacental blood infiltrates the myometrium, appearing as a bluish-purple discoloration. * **Associated Complication:** Abruption is the most common cause of **DIC** (Disseminated Intravascular Coagulation) in pregnancy due to the release of thromboplastin into the maternal circulation.

Question 202: Regarding trophoblast invasion of maternal spiral arteries, all are true except?

A. First wave occurs before 12 weeks and consists of invasion up to the border between decidua and myometrium.
B. Second wave occurs between 12 and 16 weeks with invasion of intramyometrial segments of spiral arteries.
C. Narrow lumen, muscular spiral arteries are converted into dilated, low resistance vessels.
D. Invasion by trophoblasts involves both decidual spiral arteries and decidual veins. (Correct Answer)

Explanation: ### Explanation The physiological transformation of spiral arteries is a critical process for establishing a successful pregnancy. This process is mediated by **extravillous trophoblasts**, which specifically target the arterial system to ensure a high-flow, low-resistance blood supply to the placenta [1]. **Why Option D is the Correct Answer (The False Statement):** Trophoblast invasion is a **selective process** that involves only the **spiral arteries**. It does not involve the decidual veins [2]. The goal is to destroy the muscular and elastic tissue of the arterial walls to prevent vasoconstriction; since veins are already low-pressure, thin-walled vessels, such remodeling is unnecessary and does not occur [1]. **Analysis of Other Options:** * **Option A (True):** The **First Wave** occurs between 6–12 weeks. Trophoblasts invade the decidual segments of the spiral arteries up to the deciduo-myometrial junction [1]. * **Option B (True):** The **Second Wave** occurs between 16–20 weeks (starting around 12 weeks). This wave is deeper, involving the invasion of the intramyometrial segments of the spiral arteries [1]. * **Option C (True):** The primary physiological outcome is the conversion of high-resistance, narrow-lumen vessels into **dilated, tortuous, low-resistance channels** that are unresponsive to maternal vasomotor influences [1]. **Clinical Pearls for NEET-PG:** * **Preeclampsia Connection:** Failure or incomplete "Second Wave" invasion (limited to decidual segments) is the hallmark pathophysiology of **Preeclampsia** and **IUGR** [1]. * **Nitabuch’s Layer:** This is a zone of fibrinoid degeneration where invading trophoblasts meet the decidua; it prevents overly deep invasion (Placenta Accreta occurs if this layer is absent) [1]. * **Endovascular vs. Interstitial:** Trophoblasts invade both through the vessel lumen (endovascular) and through the stroma (interstitial) [1].

Question 203: In a patient receiving magnesium sulfate therapy, at what serum magnesium level does the patellar (knee) reflex typically disappear?

A. 6-8 mEq/L
B. 10-12 mEq/L (Correct Answer)
C. 12-14 mEq/L
D. Greater than 15 mEq/L

Explanation: ### Explanation Magnesium sulfate ($MgSO_4$) is the drug of choice for seizure prophylaxis in pre-eclampsia and control in eclampsia. It acts as a CNS depressant and neuromuscular blocker. Because it is excreted almost entirely by the kidneys, toxicity is a significant risk, especially in patients with renal impairment. Monitoring clinical signs is vital because they disappear in a predictable, sequential order as serum levels rise. **1. Why Option B is Correct:** The **patellar reflex (knee jerk)** is the first clinical sign of magnesium toxicity. It typically disappears when serum magnesium levels reach **10–12 mEq/L** (or 8–10 mg/dL). This occurs because magnesium inhibits the release of acetylcholine at the neuromuscular junction, blocking the deep tendon reflex arc. **2. Analysis of Incorrect Options:** * **Option A (6–8 mEq/L):** This is the **therapeutic range** required for seizure prophylaxis. At this level, reflexes are present, and the patient is hemodynamically stable. * **Option C (12–14 mEq/L):** At these levels, **respiratory depression** and narcosis occur. This is a critical emergency requiring immediate intervention. * **Option D (>15 mEq/L):** Levels exceeding 15–20 mEq/L lead to **cardiac arrest** due to the direct effect of magnesium on the cardiac conduction system (heart block). **3. Clinical Pearls for NEET-PG:** * **Antidote:** 10 ml of 10% **Calcium Gluconate** IV (administered over 10 minutes). * **Monitoring Parameters:** Before every dose, check for: 1. Presence of patellar reflex (earliest sign of toxicity). 2. Respiratory rate >12–14/min. 3. Urine output >30 ml/hr (as magnesium is renally excreted). * **Therapeutic Level Conversion:** 4–7 mEq/L is approximately 4.8–8.4 mg/dL. Always check the units provided in the question.

Question 204: In peripartum cardiomyopathy, cardiac failure can develop anytime during which period?

A. The antenatal period
B. The third trimester
C. The first 6 weeks postpartum
D. The last month of pregnancy or within 5 months after delivery (Correct Answer)

Explanation: **Explanation:** Peripartum Cardiomyopathy (PPCM) is a rare but life-threatening form of heart failure characterized by left ventricular systolic dysfunction (LVEF <45%) in the absence of other identifiable causes. **Why Option D is Correct:** The classic diagnostic criteria for PPCM, as defined by the National Heart, Lung, and Blood Institute (NHLBI) and the European Society of Cardiology (ESC), specify a strict temporal window: **the last month of pregnancy or within the first 5 months postpartum.** This period represents the peak physiological stress on the cardiovascular system and the time when specific triggers (like the 16kDa prolactin fragment) are most active. **Analysis of Incorrect Options:** * **Option A & B:** While cardiac failure from pre-existing conditions (like mitral stenosis) often manifests in the second trimester when blood volume peaks, PPCM is specifically a late-gestation or early-postpartum phenomenon. * **Option C:** While the first 6 weeks (the puerperium) are the most common time for PPCM to present, the diagnostic window extends up to 5 months. Restricting it to 6 weeks would miss late-onset cases. **High-Yield Clinical Pearls for NEET-PG:** * **Risk Factors:** Advanced maternal age (>30), multifetal gestation, preeclampsia, and African descent. * **Pathogenesis:** Oxidative stress leads to the cleavage of **Prolactin** into a **16kDa fragment**, which is cardiotoxic and anti-angiogenic. * **Management:** Standard heart failure therapy (diuretics, beta-blockers). **Bromocriptine** (a dopamine agonist) is a specific treatment used to inhibit prolactin secretion. * **Prognosis:** Approximately 50% of patients recover normal LV function. However, future pregnancies are contraindicated if the LVEF has not normalized due to a high risk of recurrence and mortality.

Question 205: What is the cut-off value of cervical length at 24 weeks of gestation for the prediction of preterm delivery?

A. 0.5 cm
B. 1.5 cm
C. 2.5 cm (Correct Answer)
D. 3.5 cm

Explanation: **Explanation:** The measurement of cervical length via **Transvaginal Ultrasound (TVS)** is a gold-standard screening tool for predicting spontaneous preterm birth (PTB). In clinical practice and according to standard guidelines (ACOG/RCOG), a cervical length of **<25 mm (2.5 cm)** before 24 weeks of gestation is the universally accepted threshold for identifying women at high risk for preterm delivery. **Why 2.5 cm is correct:** At 20–24 weeks, the average cervical length is approximately 35–40 mm. The 2.5 cm cut-off represents the **10th percentile** for the population. A cervix shorter than this indicates "cervical insufficiency" or premature ripening, significantly increasing the risk of delivery before 34 weeks. **Analysis of Incorrect Options:** * **0.5 cm (A):** This represents an extremely short or "effaced" cervix, indicating an imminent risk of delivery rather than a screening threshold. * **1.5 cm (B):** While this is the **5th percentile** and indicates a much higher risk, it is not the standard screening cut-off used to initiate primary interventions like progesterone. * **3.5 cm (D):** This is considered a normal, healthy cervical length at 24 weeks and carries a very high negative predictive value for preterm birth. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** TVS is superior to transabdominal ultrasound or digital examination for measuring cervical length. * **Management:** If cervical length is <2.5 cm in a singleton pregnancy, the treatment of choice is **Vaginal Progesterone**. * **Funneling:** The presence of "funneling" (opening of the internal os) often precedes cervical shortening and is a significant warning sign. * **Cervical Cerclage:** Indicated in patients with a history of prior spontaneous PTB and a current short cervix (<2.5 cm) before 24 weeks.

Question 206: Which intrauterine infections are most commonly associated with neural tube defects?

A. Cytomegalovirus (CMV) and Toxoplasma gondii
B. Toxoplasma gondii and Rubella virus (Correct Answer)
C. Rubella virus and Herpes simplex virus
D. Cytomegalovirus (CMV) and Herpes simplex virus

Explanation: **Explanation:** The development of the neural tube occurs very early in embryogenesis (completed by the 28th day after conception). While most neural tube defects (NTDs) are multifactorial or linked to folic acid deficiency, certain intrauterine infections—specifically **Toxoplasma gondii** and **Rubella virus**—are recognized as significant infectious risk factors. **1. Why the Correct Answer is Right:** * **Toxoplasma gondii:** This parasite can interfere with early neuroepithelial proliferation. While it is classically known for the triad of chorioretinitis, hydrocephalus, and intracranial calcifications, early first-trimester infection is strongly associated with severe CNS dysgenesis, including anencephaly and myelomeningocele. * **Rubella virus:** The Congenital Rubella Syndrome (CRS) is highly teratogenic during the period of organogenesis. It causes mitotic arrest and angiopathy, which can disrupt the closure of the neural tube, leading to defects alongside its classic presentation of cataracts, PDA, and sensorineural deafness. **2. Why Other Options are Incorrect:** * **Cytomegalovirus (CMV):** While CMV is the most common congenital infection, it typically causes destructive lesions (microcephaly, periventricular calcifications) rather than primary induction defects like NTDs. * **Herpes Simplex Virus (HSV):** Congenital HSV is rare; most neonatal HSV is acquired during delivery. It typically presents with skin-eye-mouth (SEM) lesions or encephalitis rather than structural NTDs. **Clinical Pearls for NEET-PG:** * **Highest Risk Period:** The risk of structural malformations (like NTDs) is highest when the infection occurs in the **first trimester**. * **Prevention:** Periconceptional **Folic Acid (400 mcg/day)** is the most effective way to reduce NTD incidence by 70%. * **Screening:** Maternal **alpha-fetoprotein (MSAFP)** is elevated in open NTDs (Anencephaly/Spina bifida cystica).

Question 207: Which of the following is not associated with chorioamnionitis?

A. Preterm labour
B. Endometritis
C. Abruptio placentae
D. Placenta accreta (Correct Answer)

Explanation: **Explanation:** **Chorioamnionitis** (Triple I: Intrauterine Inflammation or Infection) is an acute inflammation of the fetal membranes and amniotic fluid, typically caused by ascending polymicrobial infection. **Why Placenta Accreta is the correct answer:** Placenta accreta is a **structural/anatomical abnormality** where the chorionic villi adhere directly to the myometrium due to a defect in the decidua basalis (Nitabuch’s layer). It is primarily associated with previous uterine surgery (C-sections, D&C) and placenta previa. It is **not** an infectious or inflammatory process and therefore has no causal link with chorioamnionitis. **Analysis of incorrect options:** * **Preterm Labour (A):** Infection is a leading cause of preterm labor. Bacteria release phospholipase A2, which triggers prostaglandin synthesis, leading to cervical ripening and uterine contractions. * **Endometritis (B):** Chorioamnionitis is a significant risk factor for postpartum endometritis. The bacteria present in the amniotic cavity during labor persist and invade the uterine lining after delivery. * **Abruptio Placentae (C):** Inflammation of the decidua and membranes can lead to vascular fragility and retroplacental hemorrhage. There is a well-documented bidirectional relationship where infection can trigger abruption, and chronic abruption can predispose to infection. **NEET-PG High-Yield Pearls:** * **Gold Standard Diagnosis:** Histopathological examination of the placenta/membranes. * **Clinical Diagnosis (Gibbs Criteria):** Maternal fever (>38°C) plus two of: Maternal tachycardia, fetal tachycardia, uterine tenderness, or foul-smelling liquor. * **Management:** Prompt initiation of IV antibiotics (Ampicillin + Gentamicin) and **delivery** (not necessarily C-section; vaginal delivery is preferred unless contraindicated). * **Most common organism:** *Ureaplasma urealyticum* and *Mycoplasma hominis*.

Question 208: A 25-week pregnant patient presents with severe left calf pain and swelling. The affected area is slightly edematous, with no erythema. A positive Homan sign is noted, raising concern for deep vein thrombosis. Which diagnostic modality should be ordered?

A. MRI
B. Computed tomographic scanning
C. Venography
D. Real-time ultrasonography (Correct Answer)

Explanation: **Explanation:** The clinical presentation of unilateral calf pain, swelling, and a positive Homan sign in a pregnant patient is highly suggestive of **Deep Vein Thrombosis (DVT)**. Pregnancy is a hypercoagulable state, increasing the risk of venous thromboembolism (VTE) by 4 to 5-fold. **Why Real-time Ultrasonography is correct:** Compression **Duplex Ultrasonography** (Real-time B-mode imaging combined with color Doppler) is the **first-line diagnostic modality** for suspected DVT in pregnancy. It is non-invasive, lacks ionizing radiation (making it safe for the fetus), and has high sensitivity and specificity (over 95%) for detecting proximal DVT. The primary diagnostic criterion is the **non-compressibility** of the vein under the ultrasound probe. **Why other options are incorrect:** * **MRI (Option A):** While accurate for diagnosing pelvic vein thrombosis, it is expensive, not readily available, and not the initial investigation of choice. * **Computed Tomographic Scanning (Option B):** CT involves significant ionizing radiation exposure to the fetus and requires intravenous contrast, which is generally avoided in pregnancy unless pulmonary embolism is suspected and other tests are inconclusive. * **Venography (Option C):** Once the "gold standard," it is now rarely used because it is invasive, technically difficult, and involves significant fetal radiation exposure. **Clinical Pearls for NEET-PG:** * **Left-sided Predominance:** 80-90% of pregnancy-related DVTs occur in the **left leg** due to "May-Thurner Syndrome" (compression of the left common iliac vein by the right common iliac artery). * **D-dimer:** Its utility is limited in pregnancy because D-dimer levels naturally increase with gestational age, leading to low specificity. * **Treatment:** Low Molecular Weight Heparin (LMWH) is the drug of choice. **Warfarin is contraindicated** due to teratogenicity (except in specific cases like mechanical heart valves).

Question 209: What is the recommended advice for an HIV-positive primigravida near term?

A. Treatment should be initiated before labor. (Correct Answer)
B. Avoid mixing of blood during labor.
C. Vaginal delivery is preferred.
D. Cesarean section would decrease transmission of HIV to the baby.

Explanation: **Explanation:** The primary goal in managing HIV-positive pregnancies is to achieve an undetectable viral load, which significantly reduces the risk of Mother-to-Child Transmission (MTCT). **Why Option A is Correct:** The most effective way to prevent vertical transmission is the initiation of **Antiretroviral Therapy (ART)** as early as possible. For a patient near term, starting treatment immediately is critical because the risk of transmission is highest during labor and delivery (intrapartum). ART reduces the maternal viral load, thereby decreasing the fetal exposure to the virus in genital secretions and blood. **Analysis of Incorrect Options:** * **Option B:** While avoiding the mixing of blood is a general principle, it is not a specific "advice" or "treatment protocol." Modern management focuses on pharmacological suppression rather than just mechanical avoidance. * **Option C:** Vaginal delivery is only preferred if the viral load is **<1,000 copies/mL** at 36 weeks. It is not a blanket recommendation for all HIV-positive patients. * **Option D:** While Elective Cesarean Section (ELCS) at 38 weeks reduces transmission in women with high or unknown viral loads, it does not offer additional benefits over vaginal delivery if the viral load is undetectable. Therefore, "initiating treatment" remains the priority over the mode of delivery. **High-Yield Clinical Pearls for NEET-PG:** * **Zidovudine (AZT):** Historically the drug of choice; however, the current WHO/NACO recommendation is the **TLD regimen** (Tenofovir + Lamivudine + Dolutegravir). * **Breastfeeding:** In India (NACO guidelines), exclusive breastfeeding for 6 months is recommended if replacement feeding is not AFASS (Affordable, Feasible, Acceptable, Sustainable, and Safe). * **Infant Prophylaxis:** Nevirapine syrup is typically given to the neonate for 6 weeks. * **Avoid:** Artificial Rupture of Membranes (ARM), fetal scalp electrodes, and instrumental delivery (forceps/vaccum) to minimize trauma.

Question 210: What is the most important factor affecting the outcome of twin gestation?

A. Lie of the first twin
B. Lie of the second twin
C. Chorionicity (Correct Answer)
D. Placental position

Explanation: **Explanation:** In twin gestations, **chorionicity** (the number of placentas) is the single most important factor determining both maternal and fetal prognosis. Monochorionic (MC) twins carry significantly higher risks compared to dichorionic (DC) twins due to the presence of vascular anastomoses on the placental surface. These connections can lead to unique, life-threatening complications such as **Twin-to-Twin Transfusion Syndrome (TTTS)**, Twin Anemia-Polycythemia Sequence (TAPS), and Twin Reversed Arterial Perfusion (TRAP) sequence. Additionally, MC twins have higher rates of congenital anomalies, intrauterine growth restriction (IUGR), and fetal demise. **Analysis of Options:** * **Lie of the first/second twin (A & B):** While the presentation (e.g., vertex vs. non-vertex) is crucial for determining the **mode of delivery** (vaginal vs. cesarean), it does not dictate the overall pregnancy outcome or the risk of antenatal complications. * **Placental position (D):** While a low-lying placenta (placenta previa) can cause antepartum hemorrhage, it is a general obstetric complication and not the primary driver of twin-specific morbidity. **High-Yield Clinical Pearls for NEET-PG:** * **Lambda Sign (Twin Peak Sign):** Diagnostic of **Dichorionic** twins on ultrasound (seen at the membrane-placenta junction). * **T-Sign:** Diagnostic of **Monochorionic** twins (thin membrane meeting the placenta at a 90-degree angle). * **Optimal Timing for Chorionicity:** Best determined by ultrasound in the first trimester (**10–14 weeks**). * **Perinatal Mortality:** Is 3–4 times higher in monochorionic twins compared to dichorionic twins.

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

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free