Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine Indian Medical PG Practice Questions and MCQs

Question 291: Which of the following is the investigation of choice in cholestasis of pregnancy?

A. Serum bilirubin levels
B. Serum bile acids levels (Correct Answer)
C. Serum alkaline phosphatase levels
D. Serum glutathiones transferase levels

Explanation: **Explanation:** **Intrahepatic Cholestasis of Pregnancy (ICP)** is a reversible type of hormone-influenced cholestasis that typically occurs in the third trimester. It is characterized by intense pruritus (especially on the palms and soles) without a primary rash. **Why Serum Bile Acids is the Correct Answer:** The measurement of **Total Serum Bile Acids (TSBA)** is the most sensitive and specific diagnostic test for ICP. It is considered the **investigation of choice** because bile acid levels are the first biochemical marker to rise, often preceding the elevation of liver enzymes or the onset of clinical jaundice. A level **>10 µmol/L** is diagnostic. Furthermore, the level of bile acids correlates with fetal risk; levels >40 µmol/L are associated with increased risks of preterm birth, meconium-stained liquor, and sudden intrauterine fetal death (IUFD). **Why Other Options are Incorrect:** * **Serum Bilirubin:** While bilirubin may be elevated in ICP, it occurs in less than 20% of cases and is usually a late finding. It is not sensitive enough for primary diagnosis. * **Serum Alkaline Phosphatase (ALP):** ALP levels naturally increase during pregnancy due to placental production, making it a non-specific and unreliable marker for liver pathology in pregnant patients. * **Serum Glutathione Transferase:** While this is a marker of hepatocellular damage, it is not routinely used or standardized for the diagnosis of ICP. **High-Yield Clinical Pearls for NEET-PG:** * **First-line Treatment:** Ursodeoxycholic Acid (UDCA) is the drug of choice (improves pruritus and lowers bile acid levels). * **Classic Presentation:** Pruritus that worsens at night, involving palms and soles, in the 3rd trimester. * **Fetal Monitoring:** Because of the risk of sudden IUFD, delivery is typically recommended between 37–38 weeks (or earlier if bile acids are >100 µmol/L). * **Postpartum:** Symptoms and biochemical markers typically resolve within 4–6 weeks after delivery.

Question 292: Which of the following does NOT predispose to isoimmunization in an Rh-negative female?

A. Advanced maternal age (Correct Answer)
B. Antepartum hemorrhage
C. Cesarean section
D. Post-dated pregnancy

Explanation: **Explanation:** Rh isoimmunization occurs when an Rh-negative mother is exposed to Rh-positive fetal red blood cells, leading to the production of maternal antibodies. This process requires a **feto-maternal hemorrhage (FMH)** of at least 0.1 mL. **Why Advanced Maternal Age is the Correct Answer:** Advanced maternal age (Option A) is a risk factor for chromosomal abnormalities and certain obstetric complications (like preeclampsia), but it does **not** inherently cause or increase the risk of feto-maternal hemorrhage. Therefore, it does not predispose a woman to isoimmunization. **Analysis of Incorrect Options:** * **Antepartum Hemorrhage (Option B):** Conditions like placental abruption or placenta previa involve the disruption of the placental interface, significantly increasing the risk of fetal blood entering the maternal circulation. * **Cesarean Section (Option C):** Surgical delivery is a major risk factor for FMH compared to vaginal delivery due to the manual removal of the placenta and uterine trauma. * **Post-dated Pregnancy (Option D):** As a pregnancy progresses beyond 40 weeks, the placenta begins to age (senescence), leading to micro-fractures in the chorionic villi. This increases the likelihood of spontaneous "silent" feto-maternal leaks. **NEET-PG High-Yield Pearls:** * **Most common cause of FMH:** Delivery (especially third stage of labor). * **Standard Dose:** 300 mcg of Anti-D IgG can neutralize 15 mL of fetal RBCs (or 30 mL of whole fetal blood). * **Screening:** The **Kleihauer-Betke (KB) test** is used to quantify the volume of FMH to determine if additional Anti-D doses are required. * **Critical Titer:** An Indirect Coombs Test (ICT) titer of **1:16** is generally considered the critical threshold requiring fetal surveillance (e.g., MCA-PSV doppler).

Question 293: Prenatal diagnosis of Hemophilia is best done by?

A. PCR (Correct Answer)
B. Linkage analysis
C. Cytometry
D. Microarray

Explanation: **Explanation:** **Hemophilia A and B** are X-linked recessive disorders caused by mutations in the *F8* and *F9* genes, respectively. The gold standard for prenatal diagnosis is **Polymerase Chain Reaction (PCR)**. 1. **Why PCR is the Correct Answer:** PCR allows for the direct detection of specific genetic mutations (such as the common **Intron 22 inversion** in Hemophilia A). It is the preferred method because it is highly sensitive, rapid, and requires only a minute amount of fetal DNA obtained via **Chorionic Villus Sampling (CVS)** at 10–12 weeks or **Amniocentesis** at 15–18 weeks. Modern techniques like **QF-PCR** (Quantitative Fluorescence PCR) further enhance speed and accuracy. 2. **Analysis of Other Options:** * **Linkage Analysis:** This was the traditional method used when specific mutations were unknown. It tracks the inheritance of polymorphic markers (STRs) within families. It is less preferred today because it requires DNA from multiple family members and is prone to errors due to genetic recombination. * **Cytometry (Flow Cytometry):** This is used for analyzing physical and chemical characteristics of cells (e.g., fetal cell sorting), but it cannot diagnose specific single-gene mutations like Hemophilia. * **Microarray (CMA):** While excellent for detecting submicroscopic chromosomal imbalances (deletions/duplications), it is not the primary tool for detecting the point mutations or inversions typical of Hemophilia. **Clinical Pearls for NEET-PG:** * **Most common mutation in severe Hemophilia A:** Intron 22 inversion (found in ~45% of cases). * **Sampling:** CVS is preferred over amniocentesis for earlier diagnosis (1st trimester). * **Non-invasive Prenatal Diagnosis (NIPD):** Research is shifting toward using cell-free fetal DNA (cffDNA) in maternal plasma to avoid invasive risks, though PCR remains the current clinical standard.

Question 294: What is the most common cause of anemia in pregnant women?

A. Acute blood loss
B. Iron deficiency (Correct Answer)
C. Gastrointestinal blood loss
D. Hemolytic anemia

Explanation: **Explanation:** **1. Why Iron Deficiency is the Correct Answer:** Iron deficiency anemia (IDA) is the most common cause of anemia in pregnancy worldwide, accounting for approximately **75–95% of cases**. During pregnancy, there is a significant increase in iron requirements (totaling about 1000 mg) to support the expansion of maternal red cell mass, the development of the fetus and placenta, and to compensate for blood loss during delivery. If maternal iron stores are inadequate or dietary intake is insufficient to meet these physiological demands, IDA develops. **2. Why the Other Options are Incorrect:** * **A. Acute blood loss:** While obstetric hemorrhage (e.g., placenta previa, abruption) is a leading cause of maternal morbidity, it is an acute event rather than the most common chronic cause of anemia throughout pregnancy. * **C. Gastrointestinal blood loss:** This is a common cause of IDA in non-pregnant adults (especially males and postmenopausal women). In pregnancy, however, the increased physiological demand is the primary driver. * **D. Hemolytic anemia:** These are relatively rare in pregnancy and are usually secondary to specific conditions like HELLP syndrome, infections, or inherited hemoglobinopathies (e.g., Sickle Cell Disease). **3. High-Yield Clinical Pearls for NEET-PG:** * **Physiological Anemia:** Occurs because the plasma volume increases (approx. 50%) more than the red cell mass (approx. 20–30%), leading to **hemodilution**. * **WHO Criteria for Anemia in Pregnancy:** Hemoglobin (Hb) **< 11 g/dL** (1st and 3rd trimester) and **< 10.5 g/dL** (2nd trimester). * **Best Screening Test:** Serum Ferritin (levels < 30 ng/mL are diagnostic of iron deficiency). * **Prophylactic Iron:** The Government of India (IFA program) recommends 60 mg elemental iron and 500 mcg folic acid daily for 180 days starting from the 14th week of pregnancy.

Question 295: What test is used to differentiate maternal and fetal blood?

A. APT test (Correct Answer)
B. Osmotic fragility test
C. Bubblin test
D. Kleihauer-Betke test

Explanation: **Explanation:** The **APT test** (Alkali Denaturation Test) is the gold standard for differentiating maternal blood from fetal blood, most commonly used in cases of **Vasa Previa** or when a neonate presents with bloody stools/vomitus. **1. Why APT Test is Correct:** The test relies on the biochemical property that **Fetal Hemoglobin (HbF)** is resistant to denaturation by strong bases, whereas **Adult Hemoglobin (HbA)** is not. When sodium hydroxide (NaOH) is added to the blood sample, maternal blood (HbA) turns yellow-brown (forming alkaline hematin), while fetal blood (HbF) remains pink. **2. Analysis of Incorrect Options:** * **Osmotic Fragility Test:** Used to diagnose Hereditary Spherocytosis by measuring the resistance of RBCs to hemolysis in varying concentrations of saline. * **Bubble Test (Shake Test):** A bedside test used to assess **fetal lung maturity** by checking for the presence of surfactant in amniotic fluid. * **Kleihauer-Betke (KB) Test:** While also based on HbF resistance to acid, it is used to **quantify** the volume of feto-maternal hemorrhage (FMH) in the maternal circulation (e.g., after trauma or for Rh-isoimmunization dosing), rather than differentiating pure samples of blood. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Scenario:** If a pregnant woman has vaginal bleeding and the APT test is **positive (pink)**, the diagnosis is **Vasa Previa** (fetal origin). * **KB Test Formula:** Used to calculate the dose of Anti-D. (Volume of FMH = % of fetal cells × 50). * **L/S Ratio:** The definitive lab test for fetal lung maturity (Normal > 2:1).

Question 296: A 26-year-old primigravida at 32 weeks of gestation experienced faintness and nausea when lying down, with recovery upon turning to her side or getting up. Which of the following is the most likely cause of these symptoms?

A. Reduced placental flow
B. Increased intragastric pressure
C. Increased intracranial pressure
D. Inferior vena caval compression (Correct Answer)

Explanation: **Explanation:** The clinical presentation described is a classic case of **Supine Hypotensive Syndrome** (also known as Aortocaval Compression Syndrome). **1. Why the correct answer is right:** In the third trimester, the gravid uterus is large and heavy. When the patient lies in the supine position, the uterus compresses the **Inferior Vena Cava (IVC)** against the vertebral column. This leads to: * Decreased venous return to the heart (reduced preload). * Decreased stroke volume and cardiac output. * Resultant maternal hypotension, which manifests as faintness, nausea, dizziness, and tachycardia. Symptoms are promptly relieved by turning to the **left lateral position**, which shifts the uterus off the IVC. **2. Why the incorrect options are wrong:** * **A. Reduced placental flow:** While IVC compression *can* lead to reduced uterine artery perfusion and fetal distress, it is a **consequence** of the maternal hypotension, not the primary cause of the mother’s faintness. * **B. Increased intragastric pressure:** This occurs in pregnancy due to the upward displacement of the stomach and progesterone-mediated relaxation of the esophageal sphincter, leading to GERD/heartburn, not syncopal symptoms. * **C. Increased intracranial pressure:** This would typically present with headaches, projectile vomiting, or papilledema, and is not related to maternal positioning in this context. **3. High-Yield Pearls for NEET-PG:** * **The Left Lateral Position** is the preferred position for pregnant women to maximize cardiac output and placental perfusion. * **Aortic Compression:** The gravid uterus also compresses the aorta; while this doesn't cause maternal hypotension (due to high arterial pressure), it can significantly reduce placental blood flow. * **Incidence:** Approximately 5–10% of pregnant women experience symptomatic supine hypotension. * **Clinical Tip:** Always perform obstetric examinations with a small wedge under the right hip to tilt the uterus to the left.

Question 297: Antepartum bleeding of fetal origin is:

A. Vasa previa (Correct Answer)
B. Circumvallate placenta
C. Abruptio placenta
D. Placenta previa

Explanation: **Explanation:** In **Vasa Previa**, fetal blood vessels (unprotected by Wharton’s jelly or placental tissue) run across the internal os of the cervix, usually due to a velamentous insertion of the umbilical cord or a succenturiate placental lobe. When the membranes rupture (spontaneous or artificial), these vessels are lacerated. Because the blood originates from the umbilical-placental circulation, the hemorrhage is of **fetal origin**. This is a critical emergency because the total fetal blood volume is small (~80-100 mL/kg); even minor bleeding can lead to rapid fetal exsanguination and death, while the mother remains hemodynamically stable. **Analysis of Incorrect Options:** * **Abruptio Placenta:** Bleeding occurs due to the premature separation of a normally situated placenta. The hemorrhage is **maternal** in origin, arising from the spiral arteries in the decidua basalis. * **Placenta Previa:** Bleeding occurs when the placenta is implanted in the lower uterine segment. The bleeding is **maternal**, resulting from the stretching of the lower segment and tearing of the placental attachments. * **Circumvallate Placenta:** This is a morphological variation where the chorionic plate is smaller than the basal plate. While it increases the risk of abruption or preterm labor, any associated bleeding is typically **maternal**. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Rupture of membranes + Painless vaginal bleeding + Fetal bradycardia/distress. * **Diagnostic Test:** The **Apt test** or **Ogita test** can differentiate fetal hemoglobin (HbF) from maternal hemoglobin (HbA) based on alkali resistance. * **Management:** If diagnosed prenatally via Color Doppler, a planned Cesarean section is performed at 34–36 weeks. If diagnosed during labor, immediate emergency Cesarean is mandatory.

Question 298: What is the most common congenital anomaly observed in pregnancies complicated by diabetes mellitus?

A. Multicystic kidneys
B. Oesophageal atresia
C. Neural tube defect (Correct Answer)
D. Duodenal atresia

Explanation: **Explanation:** In pregnancies complicated by pre-gestational diabetes mellitus (Type 1 or Type 2), the risk of congenital malformations is 3–4 times higher than in the general population, primarily due to the teratogenic effects of hyperglycemia during organogenesis. **Why Neural Tube Defects (NTDs) are correct:** While **Sacral Agenesis (Caudal Regression Syndrome)** is the most *specific* anomaly associated with diabetic embryopathy, it is rare. In terms of absolute frequency, **Neural Tube Defects** (such as anencephaly and spina bifida) are the **most common** major malformations seen in these patients. The risk of NTDs in diabetic pregnancies is increased nearly 10-fold compared to the non-diabetic population. **Analysis of Incorrect Options:** * **A. Multicystic kidneys:** While renal anomalies (like renal agenesis or ureteral duplication) occur more frequently in diabetic pregnancies, they are less common than CNS malformations. * **B & D. Oesophageal and Duodenal atresia:** Gastrointestinal atresias are associated with diabetic embryopathy, but their prevalence is significantly lower than that of NTDs and Cardiac defects. **High-Yield NEET-PG Pearls:** 1. **Most Common Overall:** Neural Tube Defects (specifically Anencephaly and Spina Bifida). 2. **Most Specific/Pathognomonic:** Caudal Regression Syndrome (Sacral Agenesis). 3. **Most Common Cardiac Anomaly:** Ventricular Septal Defect (VSD) and Transposition of the Great Arteries (TGA). 4. **Screening:** Maternal HbA1c levels >8.5% at conception are associated with a significantly higher risk of these anomalies. 5. **Prevention:** Strict glycemic control and high-dose Folic Acid (5 mg) pre-conceptionally are essential.

Question 299: Which of the following is NOT a risk factor for placenta previa?

A. Young maternal age (Correct Answer)
B. Multifetal gestation
C. Cigarette smoking
D. Multiparity

Explanation: **Explanation:** Placenta previa occurs when the placenta implants in the lower uterine segment, partially or completely covering the internal cervical os. The underlying pathophysiology is often related to **endometrial scarring** or a **large placental surface area**, necessitating a lower implantation site for adequate nutrition. **1. Why "Young maternal age" is the correct answer:** Advanced maternal age (typically >35 years) is a well-established risk factor for placenta previa. Conversely, **young maternal age is not a risk factor**. As women age, there is a higher likelihood of subclinical endometrial damage and atherosclerotic changes in the uterine vessels, which may predispose to low implantation. **2. Why the other options are incorrect (Risk Factors):** * **Multifetal gestation:** A larger placental surface area is required to support multiple fetuses, increasing the probability that the placenta will extend into the lower uterine segment. * **Cigarette smoking:** Carbon monoxide-induced hypoxemia leads to compensatory **placental hypertrophy** (increased surface area) to maximize oxygen transport, raising the risk of previa. * **Multiparity:** Repeated pregnancies can cause permanent changes in the endometrium and uterine vasculature, favoring lower implantation in subsequent gestations. **High-Yield Clinical Pearls for NEET-PG:** * **Most significant risk factor:** Previous Cesarean Section (risk increases linearly with the number of prior C-sections). * **Classic Presentation:** Painless, bright red, causative-less, recurrent vaginal bleeding in the third trimester. * **Gold Standard Diagnosis:** Transvaginal Ultrasound (TVUS) is safer and more accurate than transabdominal ultrasound. * **Management Contraindication:** Digital vaginal examination is strictly contraindicated (can trigger torrential hemorrhage). Always perform a speculum exam only after placental location is confirmed.

Question 300: A 25-year-old woman, G2P1L1, at 8 weeks gestation, with RhD negative status and a non-sensitized pregnancy, has had a spontaneous complete miscarriage. What is the dose of Anti-D immunoglobulin to be given?

A. Anti-D not required (Correct Answer)
B. 250 IU
C. 500 IU
D. Quantity of fetomaternal bleed should be tested before giving Anti-D

Explanation: ### Explanation **1. Why the correct answer is right:** The primary objective of Anti-D administration is to prevent Rh-isoimmunization. In a **spontaneous complete miscarriage occurring before 12 weeks of gestation**, the risk of significant fetomaternal hemorrhage (FMH) is negligible because the fetal erythropoiesis and circulation are not sufficiently developed to cause maternal sensitization. According to standard guidelines (including RCOG and many national protocols), Anti-D prophylaxis is **not required** for spontaneous complete miscarriages before 12 weeks, provided there is no surgical intervention (like D&C) or heavy bleeding. **2. Why the incorrect options are wrong:** * **Option B (250 IU) & C (500 IU):** These doses are indicated for "sensitizing events" occurring before 20 weeks (e.g., threatened miscarriage, ectopic pregnancy, or surgical evacuation). Since a spontaneous complete miscarriage at 8 weeks is not considered a sensitizing event, these doses are unnecessary. * **Option D (Testing FMH):** Testing for the quantity of fetomaternal bleed (e.g., Kleihauer-Betke test) is typically indicated only after **20 weeks** of gestation to calculate the required dose of Anti-D. It is not performed in the first trimester. **3. Clinical Pearls for NEET-PG:** * **The "12-Week Rule":** Anti-D is generally indicated for all Rh-negative non-sensitized women after any miscarriage/abortion **after 12 weeks**. * **Exceptions before 12 weeks:** Anti-D **must** be given if there is: 1. Ectopic pregnancy. 2. Molar pregnancy. 3. Therapeutic termination of pregnancy (Medical or Surgical). 4. Heavy vaginal bleeding in a threatened miscarriage. * **Standard Doses:** * < 20 weeks: 250 IU (or 50 mcg). * > 20 weeks: 1500 IU (or 300 mcg). * **Timeframe:** Anti-D should ideally be given within **72 hours** of the event, but it still provides some benefit if given up to 10 days later.

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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