Maternal-Fetal Medicine Practice Questions

Q: 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?

Real-time ultrasonography. **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).

Q: What is the ideal management for a 37-week pregnant elderly primigravida with placenta previa and active bleeding?

Cesarean section. **Explanation:** The correct management is **Cesarean section** because the patient is at term (37 weeks) and presenting with active bleeding due to placenta previa. In placenta previa, the placenta is implanted over the internal os; as the cervix dilates, the placental attachments are sheared, leading to life-threatening maternal hemorrhage and fetal distress. 1. **Why Cesarean Section is Correct:** At 37 weeks, the fetus is mature. Since the placenta obstructs the birth canal, vaginal delivery is contraindicated as it would cause massive bleeding. Immediate delivery via Cesarean section is the definitive treatment to save both mother and child when there is active bleeding at term. 2. **Why other options are incorrect:** * **Labor induction/Vaginal delivery:** These are contraindicated in placenta previa (especially if the edge is <2cm from the os) because the presenting part cannot engage, and cervical dilation will cause catastrophic hemorrhage. * **Expectant management (MacAfee regime):** This is only indicated if the pregnancy is <37 weeks, the bleeding is slight/stopped, and both mother and fetus are stable. Since this patient is 37 weeks (term) and has active bleeding, expectant management is no longer appropriate. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Transvaginal Ultrasound (TVS) is the most accurate and safe method to localize the placenta. * **Contraindication:** Never perform a per-vaginal (PV) examination in a case of antepartum hemorrhage until placenta previa is ruled out, as it can provoke torrential bleeding (the "Stallworthy's sign" may be seen on abdominal exam). * **Elderly Primigravida:** This factor increases the risk of complications, further favoring a controlled surgical delivery.

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

Chorionicity. **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.

Q: A multigravida with previous 2 normal deliveries presents with unstable lie of the fetus at 34 weeks gestation. What is the most probable cause?

Placenta previa. **Explanation:** An **unstable lie** refers to a situation where the fetal presentation frequently changes (e.g., from transverse to oblique to longitudinal) after 37 weeks, though it is often clinically significant from 34 weeks onwards. **Why Placenta Previa is the Correct Answer:** In a multigravida, the most common cause of an unstable lie is **placenta previa**. When the placenta occupies the lower uterine segment, it acts as a physical barrier, preventing the fetal head from engaging or settling into the maternal pelvis. This "crowding" of the lower segment forces the fetus to remain high and mobile, leading to malpresentations or an unstable lie. **Analysis of Incorrect Options:** * **Oligohydramnios:** Reduced amniotic fluid typically leads to a **fixed** malpresentation (like breech) because the fetus lacks the fluid volume necessary to move or change positions. * **Uterine Anomaly:** While conditions like a subseptate or bicornuate uterus can cause malpresentation, they are more likely to cause a **persistent** malpresentation rather than an unstable lie, and are less common in a multigravida who has already had two normal deliveries. * **Pelvic Contracture:** While a contracted pelvis prevents engagement, it is a less frequent cause of unstable lie in a multigravida compared to placenta previa, as the multiparous uterus is generally more lax. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of unstable lie:** 1. Lax abdominal wall (Multigravida), 2. Placenta previa, 3. Pelvic tumors (Fibroids). * **Management:** At 34 weeks, the management is **expectant** (observation). Active management is only indicated after 37 weeks. * **Risk:** The most dangerous complication of an unstable lie is **Cord Prolapse** following the Spontaneous Rupture of Membranes (SROM).

Q: What is the current imaging technique of choice for the diagnosis of hydatidiform mole?

Ultrasonography. **Explanation:** **Ultrasonography (USG)** is the gold standard and the primary imaging modality for diagnosing hydatidiform mole (molar pregnancy). The diagnosis is based on characteristic sonographic patterns: * **Complete Mole:** Classically presents as a **"Snowstorm appearance"** or "bunch of grapes" appearance. This represents a complex intrauterine echogenic mass with multiple small cystic spaces (hydropic villi) and the absence of fetal parts or an amniotic sac. * **Partial Mole:** May show a thickened placenta with cystic spaces and the presence of identifiable fetal tissues or a gestational sac. **Why other options are incorrect:** * **Computed Tomography (CT):** CT involves significant ionizing radiation, which is contraindicated in suspected pregnancy. While it may be used to stage gestational trophoblastic neoplasia (GTN) for distant metastasis (e.g., lungs or liver), it is not the primary diagnostic tool for the mole itself. * **Plain X-ray Abdomen:** This has no role in modern diagnosis. It cannot visualize soft tissue structures or early pregnancy and exposes the patient to unnecessary radiation. * **Magnetic Resonance Imaging (MRI):** While MRI provides excellent soft-tissue contrast and can help assess myometrial invasion in malignant cases (Choriocarcinoma), it is expensive, time-consuming, and unnecessary for the initial diagnosis when USG is highly sensitive. **High-Yield Clinical Pearls for NEET-PG:** * **Biochemical Marker:** Quantitative **beta-hCG** levels are disproportionately high for the gestational age. * **Theca Lutein Cysts:** Often seen on USG as bilateral, multiloculated ovarian cysts due to high hCG levels. * **Treatment of Choice:** Suction and Evacuation (S&E). * **Follow-up:** Weekly beta-hCG monitoring until three consecutive normal values are obtained to rule out persistent trophoblastic disease.

Question 1

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?

Accepted Answer

Real-time ultrasonography

Answer

MRI

Answer

Computed tomographic scanning

Answer

Venography

Question 2

What is the ideal management for a 37-week pregnant elderly primigravida with placenta previa and active bleeding?

Accepted Answer

Cesarean section

Answer

Labor induction

Answer

Vaginal delivery

Answer

Expectant management

Question 3

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

Accepted Answer

Treatment should be initiated before labor.

Answer

Avoid mixing of blood during labor.

Answer

Vaginal delivery is preferred.

Answer

Cesarean section would decrease transmission of HIV to the baby.

Question 4

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

Accepted Answer

Chorionicity

Answer

Lie of the first twin

Answer

Lie of the second twin

Answer

Placental position

Question 5

For karyotype analysis of stillborns, what is the recommended tissue sample, excluding which option?

Accepted Answer

Fetal skin

Answer

Umbilical cord segment about 1.5 cm long

Answer

Fetal patella

Answer

Placental block taken below cord insertion

Question 6

A multigravida with previous 2 normal deliveries presents with unstable lie of the fetus at 34 weeks gestation. What is the most probable cause?

Accepted Answer

Placenta previa

Answer

Oligohydramnios

Answer

Uterine anomaly

Answer

Pelvic contracture

Question 7

Aneuploidy is the most common genetic abnormality, accounting for up to 50% of clinical miscarriages. All are true about aneuploidy, EXCEPT?

Accepted Answer

50-60% of fetuses with trisomy 18 die between 12 weeks and 40 weeks gestation.

Answer

30-40% of fetuses with trisomy 21 die between 12 weeks and 40 weeks gestation.

Answer

The occurrence of triploidy is not related to the progression of maternal age.

Answer

In a previous pregnancy with trisomy 21 due to non-disjunction, the risk in a future pregnancy is 0.75% higher.

Question 8

A healthy 23-year-old G1P0 has had an uncomplicated pregnancy to date. She is disappointed because she is 41 weeks gestational age by good dates and a first-trimester ultrasound and wants to have her baby. She feels like she has been pregnant forever and wants to have her baby now. The patient reports good fetal movement; she has been doing kick counts for the past several days and reports that the baby moves about eight times an hour on average. On physical exam, her cervix is firm, posterior, 50% effaced, and 1 cm dilated, and the vertex is at a -1 station. As her obstetrician, what would you recommend to the patient?

Accepted Answer

Continue to monitor kick counts and return to the office in 1 week to reassess the situation

Answer

She should be admitted for an immediate cesarean section

Answer

She should be admitted for Pitocin induction

Answer

Schedule a cesarean section in 1 week if she has not undergone spontaneous labor in the meantime

Question 9

Which of the following statements is true regarding chorionicity in multifetal pregnancy?

Accepted Answer

Chorionicity is accurately determined by first trimester ultrasound scan.

Answer

Monochorionic membranes should have four layers.

Answer

Dichorionic pregnancies are always dizygotic.

Answer

Monochorionic pregnancies are always dizygotic.

Question 10

What is the current imaging technique of choice for the diagnosis of hydatidiform mole?

Accepted Answer

Ultrasonography

Answer

Computed tomography

Answer

Plain X-ray abdomen

Answer

Magnetic resonance imaging

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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