Maternal-Fetal Medicine Practice Questions

Q: Non-immune hydrops fetalis is seen in which of the following conditions?

Alpha thalassemia major. **Explanation:** **Hydrops Fetalis** is defined as the abnormal accumulation of fluid in two or more fetal compartments (e.g., ascites, pleural effusion, pericardial effusion, or skin edema). It is categorized into **Immune** (due to maternal antibodies) and **Non-Immune (NIHF)**, which now accounts for ~90% of cases. **Why Alpha Thalassemia Major is correct:** Alpha thalassemia major (Hb Bart’s; genotype --/--) is the most common cause of NIHF in Southeast Asian populations. In this condition, the absence of alpha-globin chains leads to the formation of gamma-tetramers (Hb Bart’s). These have an extremely high affinity for oxygen, failing to release it to fetal tissues. This causes **severe tissue hypoxia**, high-output cardiac failure, and subsequent hydrops. **Analysis of Incorrect Options:** * **B. Rh Incompatibility:** This is the classic cause of **Immune Hydrops Fetalis**. It occurs when a sensitized Rh-negative mother carries an Rh-positive fetus, leading to erythroblastosis fetalis. * **C. Bilateral Renal Agenesis:** This condition leads to **Oligohydramnios** (Potter sequence) due to lack of fetal urine production. It does not typically cause fluid accumulation or hydrops. * **D. Maternal Rubella:** While TORCH infections (like CMV, Syphilis, and Parvovirus B19) are major causes of NIHF, Rubella is more commonly associated with **Congenital Rubella Syndrome** (cataracts, PDA, deafness) rather than hydrops. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of NIHF worldwide:** Cardiovascular anomalies. * **Most common infectious cause of NIHF:** Parvovirus B19 (targets erythrocyte precursors leading to aplastic anemia). * **Chromosomal association:** Turner Syndrome (45, XO) is the most common chromosomal cause of NIHF (often presenting with cystic hygroma). * **Diagnosis:** Ultrasound is the gold standard; look for "Mirror Syndrome" (maternal edema mimicking fetal hydrops).

Q: What is the most common type of monozygotic twin pregnancy based on the timing of cell division between the 4th and 8th day?

Monochorionic diamniotic twins. **Explanation:** The classification of monozygotic (identical) twins depends entirely on the **timing of the division** of the fertilized ovum. 1. **Monochorionic Diamniotic (MCDA) Twins (Correct Answer):** This occurs when division happens between **days 4 and 8** post-fertilization (at the blastocyst stage). By this time, the outer layer (trophoblast) has already differentiated, but the inner cell mass has not. This results in twins sharing one placenta (monochorionic) but having separate amniotic sacs (diamniotic). This is the **most common type of monozygotic pregnancy**, accounting for approximately 70–75% of cases. 2. **Dichorionic Diamniotic (DCDA) Twins (Option D):** Division occurs early, between **days 1 and 3** (at the morula stage). Since division happens before any differentiation, each twin develops its own placenta and amniotic sac. 3. **Monochorionic Monoamniotic (MCMA) Twins (Option B):** Division occurs late, between **days 8 and 13**. By this stage, the amniotic sac has already formed, so the twins share both the placenta and the sac. 4. **Conjoined (Siamese) Twins (Option A):** Division occurs very late, **after day 13** (at the embryonic disc stage), resulting in incomplete separation. **High-Yield NEET-PG Pearls:** * **Rule of 4s:** Remember the timeline in multiples of 4: 0–4 days (DCDA), 4–8 days (MCDA), 8–12 days (MCMA), >13 days (Conjoined). * **T-sign vs. Lambda sign:** On ultrasound, MCDA twins show a **"T-sign"** (thin membrane), while DCDA twins show a **"Lambda (λ) or Twin-peak sign"** (thick membrane). * **Risk:** MCDA twins are at unique risk for **Twin-to-Twin Transfusion Syndrome (TTTS)** due to vascular anastomoses in the shared placenta.

Q: Which of the following investigations is BEST used for placental localization?

Ultrasonography. **Explanation:** **Ultrasonography (USG)** is the gold standard and the investigation of choice for placental localization. It is preferred because it is non-invasive, cost-effective, lacks ionizing radiation, and provides high accuracy (nearly 95-98%). Transvaginal Sonography (TVS) is considered superior to Transabdominal Sonography (TAS) for diagnosing placenta previa, as it allows for better visualization of the internal os and the lower placental edge without the interference of maternal obesity or a full bladder. **Why other options are incorrect:** * **X-ray (Soft tissue placentography):** Historically used to identify the placental shadow, but it is now obsolete due to low sensitivity and the risks of fetal radiation exposure. * **Amniography:** This invasive procedure involves injecting radio-opaque dye into the amniotic sac. It is outdated and carries significant risks, such as infection, premature rupture of membranes, and fetal injury. * **Clinical Examination:** Digital vaginal examination (the "Double Setup" examination) is contraindicated in suspected placenta previa unless performed in an operating theater, as it can provoke life-threatening hemorrhage. **High-Yield NEET-PG Pearls:** * **Investigation of Choice:** Transvaginal Ultrasound (TVS) is safer and more accurate than TAS for placental localization. * **MRI:** Reserved for cases of suspected **Placenta Accreta Spectrum (PAS)** where USG is inconclusive. * **Placental Migration:** The phenomenon where the placenta appears to move away from the internal os as the lower uterine segment develops; hence, a definitive diagnosis of placenta previa is usually made after 28 weeks.

Q: A pregnant lady presented with painless bleeding in the 3rd trimester. What is the most common cause?

Placenta previa. ### Explanation **Correct Answer: A. Placenta previa** **Why it is correct:** In the third trimester, bleeding per vaginum is termed **Antepartum Hemorrhage (APH)**. The hallmark clinical presentation of **Placenta Previa** (where the placenta is implanted in the lower uterine segment) is **painless, causeless, and recurrent** bright red vaginal bleeding. Since the lower segment stretches and thins out in the third trimester, the inelastic placenta separates from its attachment, leading to open maternal sinuses and bleeding. Because there is no retroplacental clot formation or uterine tension, the patient does not experience pain. **Why the other options are incorrect:** * **B. Abruptio placentae:** This is the premature separation of a normally situated placenta. It typically presents with **painful** vaginal bleeding, uterine tenderness, and a "woody hard" uterus. It is the most common cause of *painful* APH. * **C. Vesicular mole:** While this causes vaginal bleeding, it typically presents in the **first or early second trimester** (usually before 20 weeks). It is characterized by "white currant" or grape-like vesicles and disproportionately high hCG levels. **NEET-PG High-Yield Pearls:** * **Investigation of Choice:** Transvaginal Ultrasound (TVS) is the gold standard for diagnosing the location of the placenta (safer and more accurate than transabdominal). * **The "Golden Rule":** Never perform a per-vaginal (PV) examination in a case of APH until Placenta Previa is ruled out by ultrasound, as it can provoke torrential, life-threatening hemorrhage (Stallworthy's sign). * **Most common cause of APH:** Abruptio placentae (overall), but for *painless* bleeding, it is always Placenta Previa.

Q: What is the earliest indication of concealed acute bleeding in pregnancy?

Tachycardia. **Explanation:** In the setting of acute concealed bleeding (such as abruptio placentae or ruptured ectopic pregnancy), the body initiates compensatory mechanisms to maintain perfusion to vital organs. **1. Why Tachycardia is correct:** Tachycardia is the **earliest clinical sign** of hypovolemia. When blood volume decreases, venous return to the heart drops, leading to a decrease in stroke volume. To maintain cardiac output ($CO = HR \times SV$), the sympathetic nervous system is activated, increasing the heart rate. In pregnant women, this sign is critical because they can lose up to 30-35% of their blood volume before a significant drop in blood pressure occurs, making tachycardia a more sensitive early indicator than hypotension. **2. Why other options are incorrect:** * **Postural Hypotension:** While an early sign of volume depletion, it requires changing the patient's position to elicit. In acute obstetric emergencies, tachycardia is often observed first during primary assessment. * **Oliguria:** This is a later sign indicating significant renal hypoperfusion and established shock (usually Stage III hemorrhage). * **Low body temperature:** Hypothermia is a late finding associated with the "lethal triad" of trauma/hemorrhage (acidosis, coagulopathy, and hypothermia) and indicates severe, decompensated shock. **Clinical Pearls for NEET-PG:** * **The "Rule of 30":** In obstetric hemorrhage, a systolic BP drop of 30 mmHg, a heart rate increase of 30 bpm, or a 30% loss of blood volume indicates significant distress. * **Shock Index (SI):** Defined as $HR / SBP$. A value $> 0.9$ in pregnancy is a highly sensitive marker for significant concealed hemorrhage and the need for transfusion. * **Note:** Always remember that due to the physiological hypervolemia of pregnancy, "normal" vital signs can be deceptive. Tachycardia should always be investigated.

Q: What is the minimum percentage difference in weight between twins to diagnose twin discordance, considering the larger twin as the index?

20%. **Explanation:** **Twin discordance** refers to a significant size disparity between twins in a multiple pregnancy. It is a critical clinical marker because it increases the risk of perinatal morbidity and mortality, particularly for the smaller twin. **Why 20% is the Correct Answer:** The standard clinical definition for twin discordance is a **birth weight difference of 20% or more**. This is calculated using the larger twin as the index (denominator) to determine the percentage lag of the smaller twin. The formula used is: *[(Weight of larger twin – Weight of smaller twin) / Weight of larger twin] × 100.* While some older literature mentioned 15% and some severe cases are defined at 25%, the **ACOG (American College of Obstetricians and Gynecologists)** and most standard textbooks (like Williams Obstetrics) recognize **20%** as the threshold for diagnosis. **Analysis of Incorrect Options:** * **15% (Options A & B):** While a 15% difference may warrant closer monitoring, it is generally considered within the range of biological variation and does not meet the formal diagnostic criteria for discordance. * **25% (Option D):** A 25% difference is considered "severe discordance" and is associated with a significantly higher risk of fetal demise, but it is not the *minimum* percentage required for the initial diagnosis. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Cause:** In dizygotic twins, it is usually due to genetic potential or placental insufficiency. In monochorionic twins, it is often due to **TTTS (Twin-to-Twin Transfusion Syndrome)** or selective fetal growth restriction (sFGR). * **Ultrasound Diagnosis:** Antenatally, discordance is suspected if there is a **20% difference in Estimated Fetal Weight (EFW)** or an abdominal circumference (AC) difference of >20 mm. * **Monochorionic vs. Dichorionic:** Discordance is more dangerous in monochorionic twins due to shared placental vasculature.

Q: A 28-week pregnant multigravida with preeclampsia presented with fulminant signs. An urgent C-section was planned. What is the best method for the diagnosis of lung maturity?

Phosphatidyl glycerol estimation in amniotic fluid. **Explanation:** The assessment of fetal lung maturity (FLM) is crucial in high-risk pregnancies like severe preeclampsia where preterm delivery is indicated. **Why Phosphatidylglycerol (PG) is the correct answer:** Phosphatidylglycerol is a minor constituent of surfactant that appears late in gestation (usually after **35 weeks**). Its presence is a highly specific indicator of pulmonary maturity. The primary clinical advantage of PG estimation is that its validity is **not affected by contamination** with blood, meconium, or vaginal secretions. In a fulminant case requiring urgent C-section, where amniotic fluid may be contaminated during collection, PG remains the most reliable diagnostic marker. **Analysis of Incorrect Options:** * **L/S Ratio (Lecithin/Sphingomyelin):** While an L/S ratio >2.0 generally indicates maturity, it is highly sensitive to contamination. Blood or meconium can falsely alter the ratio, making it less reliable in emergency or complicated presentations. * **Bilirubin in Amniotic Fluid:** This is measured via spectrophotometry ($\Delta OD_{450}$) primarily to assess the severity of **Rh isoimmunization** and fetal hemolysis, not lung maturity. * **Amniotic Fluid Creatinine:** This was historically used to estimate **fetal renal maturity** and muscle mass (values >2 mg/dL suggest a term fetus), but it is an indirect and unreliable marker for lung maturity. **Clinical Pearls for NEET-PG:** * **Gold Standard:** L/S ratio is often cited as the traditional gold standard, but **PG** is the most specific. * **Diabetes Mellitus:** In diabetic pregnancies, the L/S ratio may be >2.0, yet the fetus can still develop RDS. Therefore, the presence of **PG** is mandatory to confirm maturity in diabetic mothers. * **Lamellar Body Count:** A rapid, modern automated test; a count >30,000–50,000/µL indicates maturity.

Q: A 28-year-old female presents with a 6-week history of amenorrhea and abdominal pain. Ultrasound reveals fluid in the pouch of Douglas. Aspiration yields dark blood that fails to clot. What is the most probable diagnosis?

Ruptured ectopic pregnancy. ### Explanation **Correct Answer: B. Ruptured ectopic pregnancy** The clinical triad of **amenorrhea, abdominal pain, and vaginal bleeding** in a reproductive-age woman is highly suggestive of an ectopic pregnancy. The ultrasound finding of fluid in the Pouch of Douglas (POD) indicates hemoperitoneum. The definitive diagnostic clue here is the aspiration of **dark, non-clotting blood** via culdocentesis. This occurs because the blood has been present in the peritoneal cavity for some time, leading to **defibrination** (lysis of fibrin by the pelvic peritoneum), which prevents it from clotting. **Why the other options are incorrect:** * **A. Ruptured ovarian cyst:** While this can cause acute pain and fluid in the POD, it usually presents with serous fluid or fresh blood (which may clot) and is less likely to be associated with a history of amenorrhea. * **C. Red degeneration of fibroid:** This typically occurs during the second or third trimester of pregnancy due to rapid growth and ischemia. It presents with localized pain and tenderness over the fibroid, not with hemoperitoneum or non-clotting blood in the POD. * **D. Pelvic abscess:** Aspiration would yield **pus** (purulent fluid) rather than blood. Patients usually present with high-grade fever, leucocytosis, and signs of pelvic inflammatory disease (PID). **High-Yield Clinical Pearls for NEET-PG:** * **Culdocentesis:** Aspiration of non-clotting blood from the POD is a classic (though now less frequently used) sign of ruptured ectopic pregnancy. * **Most common site:** The **Ampulla** of the fallopian tube is the most common site for ectopic pregnancy. * **Most common site for rupture:** The **Isthmus** (due to its narrow lumen, it ruptures early, around 6–8 weeks). * **Gold Standard Diagnosis:** Transvaginal Ultrasound (TVS) combined with quantitative β-hCG levels (Discriminatory zone: 1500–2000 mIU/mL).

Question 1

Non-immune hydrops fetalis is seen in which of the following conditions?

Accepted Answer

Alpha thalassemia major

Answer

Rh incompatibility

Answer

Bilateral renal agenesis

Answer

Maternal rubella

Question 2

What is the most common type of monozygotic twin pregnancy based on the timing of cell division between the 4th and 8th day?

Accepted Answer

Monochorionic diamniotic twins

Answer

Siamese presentation of monochorionic monoamniotic twins

Answer

Monochorionic monoamniotic twins

Answer

Dichorionic diamniotic twins

Question 3

Which of the following investigations is BEST used for placental localization?

Accepted Answer

Ultrasonography

Answer

X-ray

Answer

Amniography

Answer

Clinical examination

Question 4

What is the most common cause of placenta previa?

Accepted Answer

Previous cesarean section

Answer

Myomectomy

Answer

Primigravida

Answer

Multigravida

Question 5

A pregnant lady presented with painless bleeding in the 3rd trimester. What is the most common cause?

Accepted Answer

Placenta previa

Answer

Abruptio placentae

Answer

Vesicular mole

Answer

None of the above

Question 6

Surgery for mitral stenosis during pregnancy is ideally performed at which gestational age?

Accepted Answer

14 weeks

Answer

20 weeks

Answer

28 weeks

Answer

32 weeks

Question 7

What is the earliest indication of concealed acute bleeding in pregnancy?

Accepted Answer

Tachycardia

Answer

Oliguria

Answer

Postural hypotension

Answer

Low body temperature

Question 8

What is the minimum percentage difference in weight between twins to diagnose twin discordance, considering the larger twin as the index?

Accepted Answer

20%

Answer

15%

Answer

15%

Answer

25%

Question 9

A 28-week pregnant multigravida with preeclampsia presented with fulminant signs. An urgent C-section was planned. What is the best method for the diagnosis of lung maturity?

Accepted Answer

Phosphatidyl glycerol estimation in amniotic fluid

Answer

L/S ratio in amniotic fluid

Answer

Bilirubin in amniotic fluid

Answer

Amniotic fluid creatinine

Question 10

A 28-year-old female presents with a 6-week history of amenorrhea and abdominal pain. Ultrasound reveals fluid in the pouch of Douglas. Aspiration yields dark blood that fails to clot. What is the most probable diagnosis?

Accepted Answer

Ruptured ectopic pregnancy

Answer

Ruptured ovarian cyst

Answer

Red degeneration of fibroid

Answer

Pelvic abscess

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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