Maternal-Fetal Medicine Practice Questions

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

Late deceleration. **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.

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

Ultrasound abdomen. **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.

Q: A 25-year-old female, 5 months pregnant, presents for the first time without prior prenatal care. She is 168 cm tall, weighs 59 kg, and her blood pressure is 120/84 mm Hg. Fundal height is 17 cm, fetal movements are appreciated, and FHR is 140/min. Her past medical history is significant for hypertension, for which she takes enalapril. Dipstick results are negative. Which of the following tests should be performed?

Ultrasound of fetal kidneys. **Explanation:** The core issue in this clinical scenario is the use of **Enalapril**, an ACE inhibitor (ACEi), during pregnancy. ACE inhibitors are known teratogens, specifically categorized as FDA Category D. **1. Why Ultrasound of Fetal Kidneys is Correct:** ACE inhibitors interfere with the fetal renin-angiotensin-aldosterone system (RAAS), which is essential for normal fetal renal development and function. Exposure, particularly in the second and third trimesters, leads to **ACE inhibitor fetopathy**. This is characterized by fetal renal tubular dysgenesis, which results in **oligohydramnios** (due to decreased fetal urine production). This can further lead to pulmonary hypoplasia, limb contractures, and calvarial hypoplasia. Therefore, an ultrasound to assess fetal kidneys and amniotic fluid volume is the immediate priority. **2. Why Other Options are Incorrect:** * **A. Chorionic Villus Sampling (CVS):** CVS is typically performed between 10–13 weeks of gestation. At 5 months (approx. 20 weeks), it is too late for CVS. * **B. Group B Streptococcus (GBS) testing:** Screening for GBS is routinely performed between 36 0/7 and 37 6/7 weeks of gestation, not at 20 weeks. * **C. Triple test:** This screening for aneuploidies and neural tube defects is performed between 15–20 weeks. While the patient is in this window, the immediate risk posed by ACEi exposure (structural renal damage) takes precedence, and ultrasound is a better diagnostic tool for both anatomy and potential complications. **Clinical Pearls for NEET-PG:** * **ACEi/ARBs in Pregnancy:** Contraindicated. They cause renal agenesis, oligohydramnios, and "Potter-like" sequence. * **Antihypertensives of Choice:** Labetalol (1st line), Methyldopa, or Nifedipine. * **Critical Window:** While ACEi are most dangerous in the 2nd/3rd trimester for renal issues, 1st-trimester exposure is linked to cardiac and CNS malformations.

Q: What is the surest sign of intrauterine fetal death?

Gas in the aorta. **Explanation:** Intrauterine Fetal Death (IUFD) is diagnosed through various radiological and clinical signs. The **surest (most specific and earliest) sign** of fetal death is the presence of **gas in the fetal heart or great vessels (Aorta)**, known as **Robert’s Sign**. 1. **Why "Gas in the Aorta" is correct:** Robert’s Sign occurs due to the release of gases (mainly nitrogen) from the decomposition of fetal blood. It can appear on an X-ray or ultrasound as early as **6 to 12 hours** after death. Because gas cannot exist within the circulatory system of a living fetus, its presence is a pathognomonic and definitive indicator of fetal demise. 2. **Analysis of Incorrect Options:** * **Small sized fetus:** This is non-specific. A small fetus may indicate Intrauterine Growth Restriction (IUGR) or incorrect dating rather than death. * **Overriding of cranial bones (Spalding’s Sign):** While a classic sign, it is **not the surest**. It occurs due to the liquefaction of the brain and loss of intracranial pressure, causing the vault bones to collapse. Crucially, it takes **4 to 7 days** to develop and can be a false positive in a living fetus during labor (due to molding). * **Spalding's Sign:** (See above). It is a late sign compared to Robert's Sign. **High-Yield Clinical Pearls for NEET-PG:** * **Robert’s Sign:** Gas in fetal vessels (Earliest sign, ~12 hours). * **Spalding’s Sign:** Overriding of skull bones (Late sign, >4 days). * **Deuel’s Halo Sign:** Edema of the fetal scalp causing a "halo" appearance (due to fluid accumulation in subcutaneous tissues). * **Curvature of the Spine:** Excessive angulation of the fetal spine due to loss of muscle tone. * **Gold Standard:** The investigation of choice for IUFD today is **Ultrasonography**, demonstrating the absence of fetal cardiac activity.

Q: What is the most common cause of thrombocytopenia in pregnancy?

Benign gestational thrombocytopenia. **Explanation:** **Gestational Thrombocytopenia** (also known as incidental thrombocytopenia of pregnancy) is the most common cause of a low platelet count during pregnancy, accounting for approximately **70–80% of cases**. It is a diagnosis of exclusion characterized by a mild decrease in platelets (typically >70,000/µL, but most often >100,000/µL) occurring in the mid-to-late second or third trimester. The underlying mechanism is thought to be a combination of hemodilution (increased plasma volume) and accelerated platelet consumption in the placenta. It is "benign" because it does not affect the fetus (no fetal thrombocytopenia) and resolves spontaneously within 1–2 months postpartum. **Analysis of Incorrect Options:** * **Option A & C (Immune/Idiopathic Thrombocytopenia):** ITP is the most common cause of isolated thrombocytopenia in the **first trimester**. Unlike gestational thrombocytopenia, ITP can cause severe thrombocytopenia (<50,000/µL) and carries a risk of neonatal thrombocytopenia as IgG antibodies can cross the placenta. * **Option B (Incidental Thrombocytopenia):** While this is a synonym for gestational thrombocytopenia, "Benign Gestational Thrombocytopenia" is the more specific clinical terminology used in standard textbooks (like Williams Obstetrics) to describe this physiological variant. **NEET-PG High-Yield Pearls:** * **Platelet Cut-off:** Gestational thrombocytopenia rarely drops below 70,000/µL. If platelets are 70,000–80,000/µL. * **Second most common cause:** Preeclampsia/HELLP syndrome (approx. 20% of cases).

Question 1

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

Accepted Answer

32 weeks

Answer

20 weeks

Answer

36 weeks

Answer

28 weeks

Question 2

The

Accepted Answer

Spina bifida

Answer

Anencephaly

Answer

Agenesis of corpus callosum

Answer

Cystic hygroma

Question 3

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

Accepted Answer

Late deceleration

Answer

Variable deceleration

Answer

Sinusoidal deceleration

Answer

Early deceleration

Question 4

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

Accepted Answer

Ultrasound abdomen

Answer

Laparoscopy

Answer

CT scan

Answer

Shielded X-ray

Question 5

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

Accepted Answer

Antepartum hemorrhage

Answer

Postpartum hemorrhage

Answer

Puerperal infection

Answer

Puerperal thromboembolism

Question 6

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

Accepted Answer

Abdominal circumference is the most accurate measurement for assessing IUGR.

Answer

Abdominal circumference (AC) is the least sensitive parameter for detection of IUGR.

Answer

In asymmetric IUGR, the head circumference/abdominal circumference (HC/AC) ratio is reduced.

Answer

Serial biparietal diameter (BPD) is the only important measurement in IUGR.

Question 7

Which of the following statements regarding twin pregnancy is false?

Accepted Answer

The most common type of dizygotic twins occurs through superfecundation.

Answer

The frequency of monozygotic twins is 1 in 250 pregnancies.

Answer

Division after the formation of the embryonic disk results in conjoined twins.

Answer

A dichorionic twin pregnancy can also denote monozygotic twins.

Question 8

A 25-year-old female, 5 months pregnant, presents for the first time without prior prenatal care. She is 168 cm tall, weighs 59 kg, and her blood pressure is 120/84 mm Hg. Fundal height is 17 cm, fetal movements are appreciated, and FHR is 140/min. Her past medical history is significant for hypertension, for which she takes enalapril. Dipstick results are negative. Which of the following tests should be performed?

Accepted Answer

Ultrasound of fetal kidneys

Answer

Chorionic Villus Sampling (CVS)

Answer

Group B Streptococcus testing

Answer

Triple test

Question 9

What is the surest sign of intrauterine fetal death?

Accepted Answer

Gas in the aorta

Answer

Small sized fetus

Answer

Overriding of cranial bones

Answer

Spalding's sign

Question 10

What is the most common cause of thrombocytopenia in pregnancy?

Accepted Answer

Benign gestational thrombocytopenia

Answer

Immune thrombocytopenia

Answer

Incidental thrombocytopenia

Answer

Idiopathic thrombocytopenia

Maternal-Fetal Medicine — MCQs

Maternal-Fetal Medicine — MCQs

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