Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine Indian Medical PG Practice Questions and MCQs

Question 701: The concentration of lecithin relative to sphingomyelin begins to rise in which week of gestation?

A. 20 weeks
B. 32 weeks (Correct Answer)
C. 36 weeks
D. 28 weeks

Explanation: **Explanation:** The **Lecithin-Sphingomyelin (L/S) ratio** is a classic biochemical marker used to assess fetal lung maturity. Both substances are phospholipids produced by Type II pneumocytes and secreted into the amniotic fluid. * **Lecithin (Dipalmitoylphosphatidylcholine):** This is the major active component of surfactant. Its production remains relatively low and constant until the third trimester. * **Sphingomyelin:** A non-surfactant membrane phospholipid. Its concentration remains relatively stable throughout pregnancy or decreases slightly after 32 weeks. **Why 32 weeks is correct:** Until approximately **32-33 weeks** of gestation, the concentrations of lecithin and sphingomyelin are roughly equal (1:1). At the 32-week mark, there is a physiological surge in lecithin production as the fetal lungs mature. Consequently, the ratio begins to rise significantly from this point forward. **Analysis of Incorrect Options:** * **20 weeks:** At this stage (Canalicular period), lung development is in its early phases; surfactant production is negligible. * **28 weeks:** While surfactant starts appearing in the amniotic fluid around 24-26 weeks, the significant "rise" in the ratio relative to sphingomyelin hasn't peaked yet. * **36 weeks:** By 35-36 weeks, the L/S ratio typically reaches **2.0**, which clinically signifies mature fetal lungs and a low risk of Respiratory Distress Syndrome (RDS). This is the *endpoint* of maturity, not the *beginning* of the rise. **NEET-PG High-Yield Pearls:** 1. **L/S Ratio > 2.0:** Indicates fetal lung maturity (except in maternal diabetes, where RDS can occur even with a ratio of 2.0). 2. **Phosphatidylglycerol (PG):** Its presence is the most reliable indicator of lung maturity, especially in diabetic pregnancies. It appears around 35-36 weeks. 3. **Amniotic Fluid Index (AFI):** Often tested alongside lung maturity in high-risk pregnancies. 4. **Corticosteroids:** Administered between 24-34 weeks to accelerate this lecithin surge by inducing Type II pneumocytes.

Question 702: What is the approximate transplacental transmission rate of HIV-1?

A. 10-20%
B. 20-30%
C. 30-40% (Correct Answer)
D. 40-50%

Explanation: **Explanation:** The transmission of HIV-1 from an infected mother to her child can occur during pregnancy (antepartum), labor and delivery (intrapartum), or breastfeeding (postpartum). In the **absence of any medical intervention** (no antiretroviral therapy, vaginal delivery, and breastfeeding), the overall vertical transmission rate is approximately **30–40%**. **Breakdown of Transmission Rates:** * **In-utero (Transplacental):** ~5–10% * **During Delivery (Intrapartum):** ~10–20% * **Breastfeeding (Postpartum):** ~10–15% * **Total Cumulative Risk:** ~30–40% (This is the standard figure cited in major textbooks like Williams Obstetrics for untreated cases). **Analysis of Options:** * **Option A (10-20%):** This represents the risk associated specifically with the intrapartum period alone or the risk in non-breastfeeding populations. * **Option B (20-30%):** This is an underestimate for the total cumulative risk in a breastfeeding population without intervention. * **Option C (30-40%):** **Correct.** This reflects the global average risk of mother-to-child transmission (MTCT) when no preventive measures are taken. * **Option D (40-50%):** This is higher than the statistically observed average, though risk increases with high maternal viral load or advanced maternal disease. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Timing:** The majority of transmission (approx. 60-70% of the non-breastfeeding risk) occurs **intrapartum** due to exposure to maternal blood and vaginal secretions. * **Prevention of Parent-to-Child Transmission (PPTCT):** With effective HAART, elective cesarean section (if viral load >1000 copies/mL), and avoidance of breastfeeding, the risk can be reduced to **<2%**. * **Drug of Choice:** Zidovudine was the first drug used to reduce transmission, but current protocols (WHO/NACO) emphasize lifelong ART for all pregnant women regardless of CD4 count.

Question 703: Which is the most significant finding in cardiotocography for the detection of fetal hypoxia?

A. Late deceleration (Correct Answer)
B. Variable deceleration
C. Sinusoidal deceleration
D. Early deceleration

Explanation: **Explanation:** **1. Why Late Deceleration is the Correct Answer:** Late decelerations are the most significant and ominous CTG finding for detecting **fetal hypoxia**. They are characterized by a gradual decrease in fetal heart rate (FHR) that begins *after* the peak of the uterine contraction and returns to baseline only after the contraction has ended. This delay occurs because the contraction transiently reduces uterine blood flow; in a fetus with borderline oxygenation, this reduction pushes the fetal $PO_2$ below the critical threshold, triggering chemoreceptor-mediated vagal responses and direct myocardial depression. Persistent late decelerations indicate **uteroplacental insufficiency**. **2. Why Other Options are Incorrect:** * **Variable Deceleration:** These are the most common type of decelerations and are caused by **umbilical cord compression**. While frequent or "atypical" variables can lead to hypoxia, they are not as specific for primary uteroplacental failure as late decelerations. * **Sinusoidal Pattern:** A smooth, sine-wave-like pattern is highly specific for **severe fetal anemia** (e.g., Rh isoimmunization or vasa previa hemorrhage) rather than acute hypoxic-ischemic distress. * **Early Deceleration:** These are "mirror images" of contractions caused by **fetal head compression**. They are considered physiological (benign) and do not indicate hypoxia. **Clinical Pearls for NEET-PG:** * **Reassuring CTG:** Requires a normal baseline (110–160 bpm), moderate variability (6–25 bpm), and presence of accelerations. * **Most Sensitive Indicator:** Loss of **fetal heart rate variability** is often the earliest sign of fetal compromise, but late decelerations are the most specific for hypoxia. * **Management:** Persistent late decelerations require immediate intrauterine resuscitation (left lateral position, oxygen, IV fluids, stopping oxytocin) and prompt delivery if the pattern persists.

Question 704: A woman presents with amenorrhea of 6 weeks duration and a lump in the right iliac fossa. What is the investigation of choice?

A. Ultrasound abdomen (Correct Answer)
B. Laparoscopy
C. CT scan
D. Shielded X-ray

Explanation: **Explanation:** The clinical presentation of **amenorrhea (6 weeks)** followed by a **lump in the iliac fossa** is highly suggestive of an **Ectopic Pregnancy** or a corpus luteum cyst. In any woman of reproductive age presenting with these symptoms, the primary goal is to confirm pregnancy location and viability. **1. Why Ultrasound (USG) is the Investigation of Choice:** Ultrasound (specifically Transvaginal Sonography or TVS) is the **gold standard first-line investigation** for suspected ectopic pregnancy. It is non-invasive, cost-effective, and lacks ionizing radiation. It can identify an intrauterine gestational sac, an adnexal mass (the "blob sign" or "tubal ring sign"), or free fluid in the Pouch of Douglas (suggesting rupture). **2. Why other options are incorrect:** * **Laparoscopy:** While it is the *diagnostic gold standard* (most accurate), it is an invasive surgical procedure. It is reserved for cases where USG is inconclusive or for definitive management. * **CT Scan:** It is contraindicated in early pregnancy due to high doses of ionizing radiation, which poses a risk of teratogenicity and fetal loss. * **Shielded X-ray:** X-rays have no role in diagnosing early pregnancy or soft tissue adnexal masses. Even with shielding, the diagnostic yield is zero for this condition. **Clinical Pearls for NEET-PG:** * **Discriminatory Zone:** The level of serum β-hCG at which an intrauterine gestational sac should be visible on USG (usually **1500–2000 mIU/ml** for TVS). If β-hCG is above this and the uterus is empty, suspect ectopic pregnancy. * **Arias-Stella Reaction:** Hypersecretory endometrium seen on histology in cases of ectopic pregnancy (due to hormonal stimulation without an intrauterine implant). * **Most common site of Ectopic:** Ampulla of the Fallopian tube.

Question 705: Which of the following is NOT a serious complication of pregnancy with heart disease?

A. Antepartum hemorrhage (Correct Answer)
B. Postpartum hemorrhage
C. Puerperal infection
D. Puerperal thromboembolism

Explanation: In the context of pregnancy with heart disease, complications are categorized based on their direct impact on hemodynamic stability and the risk of cardiac failure. **Why Antepartum Hemorrhage (APH) is the Correct Answer:** While APH (such as placenta previa or abruptio placentae) is a serious obstetric emergency, it is **not** a specific or characteristic complication triggered by heart disease itself. Unlike the other options, APH does not have a direct pathophysiological link to maternal cardiac dysfunction. While severe bleeding is dangerous for any patient, it is considered an independent obstetric complication rather than a direct sequela of the cardiac state. **Analysis of Incorrect Options:** * **Postpartum Hemorrhage (PPH):** This is a critical risk. Sudden blood loss or the rapid shift of fluid from the extravascular space into the circulation after delivery can lead to acute heart failure or hypovolemic shock in a compromised heart. * **Puerperal Infection:** Infection increases the metabolic demand and heart rate (tachycardia). In a patient with valvular heart disease (especially Mitral Stenosis), tachycardia shortens diastolic filling time, potentially leading to acute pulmonary edema or subacute bacterial endocarditis (SBE). * **Puerperal Thromboembolism:** Pregnancy is a hypercoagulable state. Heart disease (especially with atrial fibrillation or prosthetic valves) significantly increases the risk of thromboembolic events, which can be fatal in the postpartum period. **NEET-PG High-Yield Pearls:** * **Most common heart disease in pregnancy (India):** Rheumatic Heart Disease (Mitral Stenosis is the most common lesion). * **Most common cause of maternal death in heart disease:** Heart failure. * **Highest risk periods for heart failure:** 28–32 weeks of gestation, during labor, and the immediate postpartum period (due to "autotransfusion" from the uterus). * **Prophylaxis:** Antibiotic prophylaxis is specifically indicated during labor to prevent Subacute Bacterial Endocarditis (SBE).

Question 706: Regarding intrauterine growth restriction (IUGR), which of the following statements is correct?

A. Abdominal circumference (AC) is the least sensitive parameter for detection of IUGR.
B. In asymmetric IUGR, the head circumference/abdominal circumference (HC/AC) ratio is reduced.
C. Serial biparietal diameter (BPD) is the only important measurement in IUGR.
D. Abdominal circumference is the most accurate measurement for assessing IUGR. (Correct Answer)

Explanation: **Explanation:** **1. Why Abdominal Circumference (AC) is the most accurate:** Intrauterine Growth Restriction (IUGR) primarily affects the fetal liver and subcutaneous fat stores. In cases of placental insufficiency, the fetus undergoes "brain-sparing," where blood is shunted away from the viscera to the brain. This leads to a depletion of glycogen stores in the liver and a reduction in abdominal fat, making the **Abdominal Circumference (AC)** the first and most significantly affected biometric parameter. It is considered the single most sensitive and accurate measurement for diagnosing IUGR and predicting fetal weight. **2. Analysis of Incorrect Options:** * **Option A:** AC is actually the **most sensitive** parameter, not the least. A small AC is often the first sign of growth restriction. * **Option B:** In asymmetric IUGR (the most common type), the head is spared while the abdomen is small. Therefore, the **HC/AC ratio is increased** (High HC, Low AC), not reduced. * **Option C:** BPD is unreliable in IUGR because it may remain normal due to brain-sparing. Furthermore, BPD can be affected by head shape (dolichocephaly). A single parameter is never sufficient; a composite of AC, HC, BPD, and Femur Length (FL) is used to calculate Estimated Fetal Weight (EFW). **Clinical Pearls for NEET-PG:** * **Ponderal Index:** Used to differentiate between symmetric and asymmetric IUGR. * **Symmetric IUGR:** Usually due to early insults (chromosomal, infections like TORCH). All parameters (HC, AC, FL) are proportionately small. * **Asymmetric IUGR:** Usually due to placental insufficiency (maternal HTN, preeclampsia). Occurs in the 3rd trimester. * **Gold Standard for Diagnosis:** Serial ultrasonography showing a lag in growth over time is more diagnostic than a single scan. * **Doppler:** Umbilical artery Doppler (showing absent or reversed end-diastolic flow) is the best tool for monitoring and deciding the timing of delivery.

Question 707: During which gestational period is the fetus most likely to be affected if the mother contracts varicella zoster infection?

A. 8-14 weeks
B. 14-28 weeks (Correct Answer)
C. 28-32 weeks
D. 32-37 weeks

Explanation: The correct answer is **B. 14-28 weeks**. ### **Medical Concept: Congenital Varicella Syndrome (CVS)** When a pregnant woman contracts primary varicella (chickenpox), the virus can cross the placenta and cause **Congenital Varicella Syndrome**. While the overall risk is low (approx. 1–2%), the period of maximum vulnerability for the fetus is between **13 and 20 weeks** of gestation. This is because this window coincides with critical organogenesis and the development of the peripheral nervous system. In the context of the given options, the range **14-28 weeks** encompasses the peak risk period (13-20 weeks) where the virus causes cicatricial skin lesions, limb hypoplasia, chorioretinitis, and microcephaly. ### **Analysis of Incorrect Options** * **A. 8-14 weeks:** While the risk exists, it is statistically lower (approx. 0.4%) compared to the second trimester. * **C & D. 28-37 weeks:** Infection in the third trimester rarely causes CVS. Instead, maternal infection near term (5 days before to 2 days after delivery) poses a high risk of **Neonatal Varicella**, which is a severe disseminated disease due to the lack of transplacental maternal antibodies. ### **NEET-PG High-Yield Pearls** * **Highest Risk Window:** 13–20 weeks (specifically cited as 2% risk). * **Clinical Triad of CVS:** 1. Cicatricial (zigzag) skin scarring; 2. Limb hypoplasia; 3. Ocular defects (chorioretinitis/cataracts). * **Management:** If a non-immune pregnant woman is exposed, administer **Varicella-Zoster Immunoglobulin (VZIG)** within 10 days (ideally 96 hours) to prevent maternal complications. * **Acyclovir:** Indicated if the mother develops clinical chickenpox to reduce the risk of maternal pneumonia. * **Neonatal Varicella:** If the mother develops a rash within 5 days before or 2 days after delivery, the neonate must receive VZIG immediately.

Question 708: What is a known consequence of maternal cocaine use during pregnancy?

A. Hydrops fetalis
B. Sacral agenesis
C. Cerebral infarction (Correct Answer)
D. Hypertrichosis

Explanation: **Explanation:** **Correct Answer: C. Cerebral infarction** Cocaine is a potent sympathomimetic agent that acts by inhibiting the reuptake of norepinephrine, epinephrine, and dopamine. This leads to profound maternal and fetal **vasoconstriction** and hypertension. In the fetus, these acute hypertensive episodes followed by reduced placental perfusion can lead to **vascular disruptive phenomena**. Cerebral infarction (stroke) and intracranial hemorrhage occur due to these sudden hemodynamic shifts. Other related complications include placental abruption (due to maternal hypertension) and limb reduction defects. **Analysis of Incorrect Options:** * **A. Hydrops fetalis:** This is typically caused by severe fetal anemia (e.g., Rh isoimmunization, Parvovirus B19) or cardiac failure. While cocaine causes growth restriction, it is not a primary cause of hydrops. * **B. Sacral agenesis:** This is a highly specific "pathognomonic" malformation associated with **maternal diabetes mellitus** (pre-gestational), not cocaine use. * **D. Hypertrichosis:** Excessive hair growth is associated with fetal alcohol syndrome (hirsutism) or certain drug exposures like phenytoin (fetal hydantoin syndrome), but not cocaine. **NEET-PG High-Yield Pearls:** * **Placental Abruption:** Cocaine is a classic risk factor frequently tested in clinical scenarios involving sudden abdominal pain and vaginal bleeding. * **Vascular Disruption:** Beyond the brain, cocaine can cause **Necrotizing Enterocolitis (NEC)** in neonates and intestinal atresia due to mesenteric ischemia. * **Teratogenicity:** Unlike alcohol, cocaine is not associated with a specific "syndrome" of dysmorphic facies but rather with growth restriction (IUGR) and microcephaly.

Question 709: Which of the following statements regarding twin pregnancy is false?

A. The frequency of monozygotic twins is 1 in 250 pregnancies.
B. Division after the formation of the embryonic disk results in conjoined twins.
C. The most common type of dizygotic twins occurs through superfecundation. (Correct Answer)
D. A dichorionic twin pregnancy can also denote monozygotic twins.

Explanation: **Explanation:** **1. Why Option C is the Correct (False) Statement:** Dizygotic (fraternal) twins typically occur due to the simultaneous release of two ova during a single ovulatory cycle, which are then fertilized by two different sperm. **Superfecundation** is a rare phenomenon where two ova are fertilized by sperm from different acts of coitus (and potentially different fathers). While it results in dizygotic twins, it is an **exception**, not the most common mechanism. **2. Analysis of Incorrect Options (True Statements):** * **Option A:** The incidence of monozygotic (MZ) twins is remarkably constant worldwide at approximately **1 in 250 pregnancies** (3.5 per 1,000 births), regardless of race, age, or parity. * **Option B:** The timing of zygotic division determines chorionicity and amnionicity. Division occurring **after day 13** (post-embryonic disk formation) results in **conjoined twins**. * **Option C:** If division occurs within the first **72 hours** (3 days) post-fertilization (at the morula stage), the resulting MZ twins will be **dichorionic-diamniotic (DCDA)**. Thus, a DCDA scan does not automatically mean the twins are dizygotic. **High-Yield Clinical Pearls for NEET-PG:** * **Hellin’s Rule:** Frequency of twins is $1:80^1$, triplets $1:80^2$, and quadruplets $1:80^3$. * **Superfecundation vs. Superfetation:** Superfecundation is fertilization of two ova in the same cycle; **Superfetation** is fertilization of two ova in different menstrual cycles (extremely rare in humans). * **Lambda ($\lambda$) Sign:** Also known as the "Twin Peak" sign; it is pathognomonic for **Dichorionic** twins on ultrasound. * **T-Sign:** Indicates **Monochorionic** twins. * The most common type of monozygotic twins is **Monochorionic Diamniotic (MCDA)**, occurring due to division between days 4–8.

Question 710: Which of the following is NOT related to anencephaly?

A. It is commonly associated with prematurity.
B. Often associated with oligohydramnios. (Correct Answer)
C. Increased association with female infants.
D. Obstructed labor may occur.

Explanation: ### Explanation **Anencephaly** is a lethal neural tube defect characterized by the absence of a major portion of the brain, skull, and scalp. **Why Option B is the correct answer (The "NOT" related factor):** Anencephaly is characteristically associated with **polyhydramnios**, not oligohydramnios. Polyhydramnios occurs due to two primary reasons: 1. **Defective Swallowing:** The absence of the swallowing reflex in the fetus prevents the clearance of amniotic fluid. 2. **Exudation:** Transudation of fluid from the exposed meninges/cerebrospinal fluid into the amniotic sac. **Analysis of other options:** * **Option A (Prematurity):** Anencephaly is strongly associated with preterm labor. This is often triggered by the overdistension of the uterus due to polyhydramnios. * **Option C (Female Predominance):** There is a well-documented female preponderance in anencephalic fetuses (ratio approximately 3:1 to 4:1). * **Option D (Obstructed Labor):** While labor is often rapid, obstructed labor can occur due to **malpresentations** (like face presentation) or the **absence of the fetal head** to act as a proper wedge to dilate the cervix effectively. Additionally, the lack of a fetal pituitary-adrenal axis can lead to post-term pregnancy, though spontaneous preterm labor is more common. **High-Yield Clinical Pearls for NEET-PG:** * **Screening:** Elevated **Alpha-fetoprotein (AFP)** in maternal serum and amniotic fluid. * **Ultrasound:** "Frog-eye appearance" or "Mickey Mouse sign" due to prominent orbits and absence of the cranial vault. * **Associated finding:** Atrophy of fetal adrenal glands (due to lack of ACTH). * **Prevention:** Periconceptional intake of **400 mcg of Folic Acid** (5 mg for high-risk cases) reduces the risk of recurrence.

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

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free