Maternal-Fetal Medicine Practice Questions

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

Advanced maternal age. **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).

Q: Prenatal diagnosis of Hemophilia is best done by?

PCR. **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.

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

Iron deficiency. **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.

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

APT test. **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).

Q: Antepartum bleeding of fetal origin is:

Vasa previa. **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.

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

Neural tube defect. **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.

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

Young maternal age. **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.

Q: 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?

Anti-D not required. ### 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: 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.

Question 1

Which of the following is the investigation of choice in cholestasis of pregnancy?

Accepted Answer

Serum bile acids levels

Answer

Serum bilirubin levels

Answer

Serum alkaline phosphatase levels

Answer

Serum glutathiones transferase levels

Question 2

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

Accepted Answer

Advanced maternal age

Answer

Antepartum hemorrhage

Answer

Cesarean section

Answer

Post-dated pregnancy

Question 3

Prenatal diagnosis of Hemophilia is best done by?

Accepted Answer

PCR

Answer

Linkage analysis

Answer

Cytometry

Answer

Microarray

Question 4

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

Accepted Answer

Iron deficiency

Answer

Acute blood loss

Answer

Gastrointestinal blood loss

Answer

Hemolytic anemia

Question 5

What test is used to differentiate maternal and fetal blood?

Accepted Answer

APT test

Answer

Osmotic fragility test

Answer

Bubblin test

Answer

Kleihauer-Betke test

Question 6

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?

Accepted Answer

Inferior vena caval compression

Answer

Reduced placental flow

Answer

Increased intragastric pressure

Answer

Increased intracranial pressure

Question 7

Antepartum bleeding of fetal origin is:

Accepted Answer

Vasa previa

Answer

Circumvallate placenta

Answer

Abruptio placenta

Answer

Placenta previa

Question 8

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

Accepted Answer

Neural tube defect

Answer

Multicystic kidneys

Answer

Oesophageal atresia

Answer

Duodenal atresia

Question 9

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

Accepted Answer

Young maternal age

Answer

Multifetal gestation

Answer

Cigarette smoking

Answer

Multiparity

Question 10

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?

Accepted Answer

Anti-D not required

Answer

250 IU

Answer

500 IU

Answer

Quantity of fetomaternal bleed should be tested before giving Anti-D

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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