Maternal-Fetal Medicine Practice Questions

Q: Mr. and Mrs. Annadurai have a 2-month-old baby with Down syndrome. Karyotype of Mrs. Annadurai shows a translocation variety of Down syndrome. Which of the following investigations will you advise to the parents before their next pregnancy?

Karyotyping. ### Explanation **Why Karyotyping is the Correct Answer:** The scenario describes a case of **Translocation Down Syndrome**. Unlike Trisomy 21 (nondisjunction), which is usually sporadic and related to maternal age, translocation Down syndrome can be inherited from a phenotypically normal parent who is a **balanced translocation carrier**. If Mrs. Annadurai has a translocation variety, there is a significant risk of recurrence in future pregnancies. To provide accurate genetic counseling and determine the specific recurrence risk (e.g., 10–15% if the mother is a carrier of a 14;21 translocation, or 100% if a parent carries a 21;21 translocation), **Karyotyping of both parents** is the essential first step before the next pregnancy. This identifies if either parent is a carrier of the balanced translocation. **Why Other Options are Incorrect:** * **Triple Test (A), Alpha-fetoprotein (B), and Beta-hCG (D):** These are components of **maternal serum screening** performed *during* pregnancy (typically between 15–20 weeks). While they help screen for Down syndrome in a current fetus, they cannot identify a parental carrier state or provide pre-conceptional risk assessment. **Clinical Pearls for NEET-PG:** * **Trisomy 21 Etiology:** 95% are due to Nondisjunction (risk increases with maternal age); 3–4% are due to Robertsonian Translocation (independent of maternal age); 1% are Mosaicism. * **Recurrence Risk:** If a previous child had Trisomy 21 (nondisjunction), the recurrence risk is ~1%. If a parent is a translocation carrier, the risk is significantly higher. * **Most Common Translocation:** The most frequent translocation in Down syndrome is **t(14;21)**. * **Pre-conceptional Counseling:** Always prioritize parental karyotyping when a structural chromosomal abnormality is identified in a proband (the affected child).

Q: A 37-week pregnant female presents with grade 3 placenta previa, vaginal bleeding, and uterine contractions. What is the most appropriate management?

Emergency lower segment Cesarean section. **Explanation:** The management of placenta previa depends on the **gestational age**, the **severity of bleeding**, and the **presence of labor**. **1. Why Option D is Correct:** The patient is at **37 weeks (term)** and is symptomatic with **vaginal bleeding and uterine contractions**. In placenta previa, uterine contractions cause cervical effacement and dilatation, which leads to further separation of the placenta and life-threatening hemorrhage. Since the pregnancy has reached term and the patient is in active labor/bleeding, immediate delivery is mandatory. For **Grade 3 (total/major)** placenta previa, vaginal delivery is contraindicated; therefore, an **Emergency Lower Segment Cesarean Section (LSCS)** is the definitive management to save both mother and fetus. **2. Why Other Options are Incorrect:** * **Option A & B:** These are components of **Macafee and Johnson’s expectant management**. This protocol is only indicated if the fetus is preterm (<37 weeks), bleeding is not life-threatening, and the patient is not in labor. * **Option C:** "Wait and watch" is dangerous in the presence of active contractions and major placenta previa at term, as it risks sudden, massive maternal hemorrhage and fetal distress. **Clinical Pearls for NEET-PG:** * **Macafee Protocol Goal:** To carry the pregnancy to 37 weeks (term). * **Contraindication:** Never perform a **per-vaginal (PV) examination** in a suspected case of placenta previa outside the operating theater ("Double Setup"), as it can provoke torrential bleeding. * **Stallworthy’s Sign:** A drop in fetal heart rate when the fetal head is pressed into the pelvis (common in posterior placenta previa). * **Gold Standard Diagnosis:** Transvaginal Ultrasound (TVS) is more accurate than transabdominal ultrasound for locating the placental edge.

Q: A 30-year-old pregnant woman visits her obstetrician for prenatal care. The patient reports that two of her three children had "yellow jaundice" at birth, and her youngest child was severely jaundiced and required two blood transfusions. Prenatal laboratory tests reveal the mother is blood type O, Rh negative, and her husband is blood type A, Rh positive. The obstetrician obtains amniotic fluid at 36 weeks of gestation to determine if the fetus is mature enough for preterm delivery. Which of the following quantitative analyses of amniotic fluid is most likely used as an indicator of fetal lung maturity?

Lecithin. **Explanation:** The correct answer is **Lecithin (D)**. **1. Why Lecithin is Correct:** The clinical scenario describes a case of **Rh isoimmunization** (Rh-negative mother, Rh-positive father, and a history of progressively worsening neonatal jaundice). In such cases, early delivery may be necessary if fetal hemolysis is severe. To ensure the fetus can survive outside the womb, **Fetal Lung Maturity (FLM)** must be assessed. Lecithin (dipalmitoylphosphatidylcholine) is the primary component of **pulmonary surfactant**. Its concentration in amniotic fluid increases significantly after 34–35 weeks of gestation. The **Lecithin/Sphingomyelin (L/S) ratio** is a classic gold standard for FLM; a ratio **>2.0** typically indicates mature lungs and a low risk of Respiratory Distress Syndrome (RDS). **2. Why Other Options are Incorrect:** * **A. Absorbance at 450 nm ($\Delta OD_{450}$):** This measures **bilirubin** levels in amniotic fluid using spectrophotometry (Liley’s Chart or Queenan Curve). While relevant to this patient's Rh isoimmunization to assess the severity of fetal anemia, it does *not* measure lung maturity. * **B. Alpha-fetoprotein (AFP):** Used to screen for **Neural Tube Defects** (elevated) or chromosomal anomalies like Down syndrome (decreased). * **C. Creatinine:** Amniotic fluid creatinine levels reflect **fetal renal maturity** and muscle mass, not pulmonary status. **3. Clinical Pearls for NEET-PG:** * **Phosphatidylglycerol (PG):** Its presence is the most reliable indicator of lung maturity, especially in **diabetic mothers**, where the L/S ratio may be falsely reassuring. * **Amniostat-FLM:** An immunological test for PG. * **Lamellar Body Count (LBC):** A rapid, automated test; a count **>30,000–50,000/µL** indicates maturity. * **Shake Test (Foam Stability Index):** A bedside screening test for surfactant.

Q: A female has a history of 6 weeks amenorrhea, and ultrasound shows no sac. Serum beta-hCG is 1000 IU/L. What is the next step in the management of this patient?

Repeat hCG after 48 hours. ### Explanation The management of a pregnancy of unknown location (PUL) depends on the **Discriminatory Zone**, which is the serum beta-hCG level above which an intrauterine gestational sac should be visible on ultrasound. For Transvaginal Sonography (TVS), this threshold is typically **1500–2000 IU/L**. **1. Why Option B is Correct:** In this patient, the beta-hCG is **1000 IU/L**, which is below the discriminatory zone. Since the ultrasound is inconclusive (no sac seen), we cannot differentiate between an early viable intrauterine pregnancy, a failing intrauterine pregnancy, or an ectopic pregnancy. The standard protocol is to **repeat serum beta-hCG after 48 hours** to assess the "doubling time." A rise of at least 35–53% suggests a viable intrauterine pregnancy, while a plateau or sub-optimal rise raises suspicion for an ectopic pregnancy. **2. Why Other Options are Incorrect:** * **Option A (Medical Management):** Administering Methotrexate or surgical intervention is premature. Without a confirmed diagnosis of ectopic pregnancy or a non-viable pregnancy above the discriminatory zone, medical management risks terminating a potentially viable early pregnancy. * **Option C (Repeat hCG after 1 week):** A one-week interval is too long. Ectopic pregnancies can rupture quickly; monitoring every 48 hours is essential for patient safety and timely diagnosis. **Clinical Pearls for NEET-PG:** * **Discriminatory Zone:** TVS = 1500–2000 IU/L; Transabdominal Scan (TAS) = 6000–6500 IU/L. * **Doubling Time:** In 85% of viable pregnancies, hCG levels rise by ≥66% every 48 hours (though 35% is the minimum acceptable rise). * **Empty uterus + hCG >2000 IU/L:** Highly suggestive of ectopic pregnancy or recent complete abortion. * **Most common site of ectopic pregnancy:** Ampulla of the Fallopian tube.

Q: What type of placental insertion is shown?

Battledore Placenta. ***Battledore Placenta*** - **Marginal cord insertion** where the umbilical cord inserts at the edge or margin of the placental disc, resembling a badminton racquet. - Associated with increased risk of **cord compression** during labor and potential **fetal growth restriction**, but generally has better outcomes than velamentous insertion. *Velamentous Insertion* - The umbilical cord inserts into the **fetal membranes** rather than the placental disc, with vessels running unprotected through the membranes. - Carries significant risk of **vasa previa** and **vessel rupture** during labor, leading to potential fetal hemorrhage and death. *Normal* - **Central cord insertion** occurs in the middle third of the placental disc, providing optimal blood flow distribution. - This is the most common and safest type of insertion, with minimal risk of complications during pregnancy and delivery. *Circumvallate* - A **placental abnormality** where the fetal membranes fold back over the fetal surface, creating a raised white ring around the placental edge. - Associated with increased risk of **placental abruption**, **preterm labor**, and **antepartum hemorrhage**.

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

Placenta previa. **Explanation:** **Why Placenta Previa is the Correct Answer:** An **unstable lie** refers to a situation where the fetal presentation frequently changes (e.g., from transverse to oblique to longitudinal) after 34 weeks of gestation. In a multigravida, the most common cause of an unstable lie or a high floating head is a **space-occupying lesion in the lower uterine segment**. Placenta previa (especially the major degrees) prevents the fetal head from engaging in the maternal pelvis, forcing the fetus into an abnormal or unstable lie. It is a classic "mechanical" obstruction. **Analysis of Incorrect Options:** * **B. Oligohydramnios:** Reduced amniotic fluid typically leads to a **fixed** malpresentation (like breech) because the fetus lacks the fluid volume to move or change positions easily. It does not cause an unstable lie. * **C. Uterine Anomaly:** While anomalies like a bicornuate or septate uterus cause malpresentations, they are more likely to result in a **persistent** malpresentation rather than an unstable one, and are more commonly associated with nulliparity or recurrent pregnancy loss. * **D. Pelvic Tumor:** A large fibroid or ovarian cyst can cause an unstable lie by obstructing the pelvic inlet, but statistically, **placenta previa** is a more frequent and high-yield clinical cause in the third trimester for multigravidas. **High-Yield Clinical Pearls for NEET-PG:** * **Management:** The management of unstable lie at 34 weeks is **expectant** (observation), as many stabilize by 37 weeks. If it persists at 37 weeks, the patient is usually admitted to the hospital. * **Rule of Thumb:** Always exclude placenta previa via ultrasound before performing any internal examination or external cephalic version (ECV) in a patient with an unstable lie or malpresentation. * **Other Causes:** Polyhydramnios, lax abdominal wall (common in multiparity), and contracted pelvis are other significant causes of unstable lie.

Question 1

Mr. and Mrs. Annadurai have a 2-month-old baby with Down syndrome. Karyotype of Mrs. Annadurai shows a translocation variety of Down syndrome. Which of the following investigations will you advise to the parents before their next pregnancy?

Accepted Answer

Karyotyping

Answer

Triple test

Answer

Alpha-fetoprotein

Answer

Beta-human chorionic gonadotropin (hCG)

Question 2

What is the normal beat-to-beat variability in a Non-Stress Test (NST) on a term fetus?

Accepted Answer

10-25 beats per minute

Answer

5-10 beats per minute

Answer

greater than 25 beats per minute

Answer

any variability above a baseline of 110 bpm is normal

Question 3

Which of the following is NOT typically performed in the management of Intrauterine Growth Restriction (IUGR)?

Accepted Answer

Amniocentesis

Answer

Non-stress test

Answer

Oxytocin challenge test

Answer

Ultrasound of the abdomen

Question 4

A 37-week pregnant female presents with grade 3 placenta previa, vaginal bleeding, and uterine contractions. What is the most appropriate management?

Accepted Answer

Emergency lower segment Cesarean section

Answer

Dexamethasone and nifedipine

Answer

Bed rest and sedation

Answer

Wait and watch

Question 5

A 30-year-old pregnant woman visits her obstetrician for prenatal care. The patient reports that two of her three children had "yellow jaundice" at birth, and her youngest child was severely jaundiced and required two blood transfusions. Prenatal laboratory tests reveal the mother is blood type O, Rh negative, and her husband is blood type A, Rh positive. The obstetrician obtains amniotic fluid at 36 weeks of gestation to determine if the fetus is mature enough for preterm delivery. Which of the following quantitative analyses of amniotic fluid is most likely used as an indicator of fetal lung maturity?

Accepted Answer

Lecithin

Answer

Absorbance at 450 nm

Answer

Alpha-fetoprotein

Answer

Creatinine

Question 6

An HIV-infected pregnant woman presents for her 36-week prenatal visit. Which of the following discussion points regarding delivery is true?

Accepted Answer

If her viral load is > 1,000 copies/mL, she will be scheduled for a cesarean delivery at 38 weeks.

Answer

All HIV-infected women should have a cesarean delivery.

Answer

She may have a vaginal delivery only if her viral load is < 100 copies/mL.

Answer

She can deliver vaginally regardless of viral load because she is on highly active antiretroviral therapy.

Question 7

A female has a history of 6 weeks amenorrhea, and ultrasound shows no sac. Serum beta-hCG is 1000 IU/L. What is the next step in the management of this patient?

Accepted Answer

Repeat hCG after 48 hours

Answer

Medical management

Answer

Repeat hCG after 1 week

Answer

None of the above

Question 8

What type of placental insertion is shown?

Accepted Answer

Battledore Placenta

Answer

Velamentous Insertion

Answer

Normal

Answer

Circumvallate

Question 9

Which of the following statements concerning polyhydramnios is true?

Accepted Answer

Complications include placental abruption, uterine dysfunction, and postpartum hemorrhage.

Answer

Acute polyhydramnios always leads to labor at the usual time.

Answer

The incidence of associated malformations is approximately 3%.

Answer

Maternal edema of the vulva and lower limbs is rare.

Question 10

A multigravida with previous 2 normal deliveries presents with an 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 tumor

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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